Sources and Magnitude of Occupational and Public Exposures from Nuclear Medicine Procedures (N C R P Report)

NCRP REPORT No. 124

SOURCES AND MAGNITUDE OF OCCUPATIONAL AND PUBLIC EXPOSURES FROM NUCLEAR MEDICINE PROCEDURES Recommendations of the NATIONAL COUNCIL O N RADIATION PROTECTION AND MEASUREMENTS

Issued March 11, 1996

National Council on Radiation Protection and Measurements I Bethesda, MD 20814-3095 7910 Woodmont Avenue

LEGAL NOTICE This report was prepared by the National Council on Radiation Protection a n d Measurements (NCRP). The Council strives to provide accurate, complete and useful information in its reports. However, neither the NCRP, the members of NCRP, other persons contributing to or assisting in the preparation of this Report, nor any person acting on the behalf of any of these parties: (a) makes any warranty or representation, express or implied, with respect to the accuracy, completeness or usefulness of the information contained i n this Report, or that the use of any information, method or process disclosed i n this Report may not infringe on privately owned rights; or (b) assumes any liability with respect to the use of, or for damages resulting from the use of any information, method or process disclosed in this Report, under the Civil Rights Act of 1964, Section 701 et seq, as amended 42 U.S.C. Section 2000e et seq. (Title VII) or any other statutory or common law theory governing liability.

Library of Congress Cataloging-in-Publication Data National Council on Radiation Protection and Measurements. Sources and magnitude of occupational and public exposures from nuclear medicine procedures / recommendations of the National Council on Radiation Protection and Measurements. cm. - (NCRP report ; no. 124) p. "Prepared by Scientific Committee 77 on Guidance on Occupational and Public Exposure Resulting from Diagnostic Nuclear Medicine Proceduresn-Pref. "Issued March 1996." Includes bibliographical references and index. ISBN 0-929600-51-7 1. Nuclear medicine-Safety measures. 2. Radiation-Dosage. I. National Council on Radiation Protection and Measurements. Scientific Committee 77 on Guidance on Occupational and Public Exposure Resulting from Diagnostic Nuclear Medicine Procedures. 11. Title. 111. Series. [DNLM: 1. Nuclear Medicine. 2. Occupational Exposure. 3. Radiation Effects. 4. Risk. 5. Radiation Protection. WN 440 N2765s 19961 RA569.N355 1996 616.9'897-dc20 DNLMfDLC for Library of Congress 96-690 CIP

Copyright O National Council on Radiation Protection and Measurements 1996 All rights reserved. This publication is protected by copyright. No part of this publication may be reproduced in any form or by any means, including photocopying, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotation in critical articles or reviews.

Preface This Report addresses the sources of exposures incurred in the practice of nuclear medicine and provides the necessary data to evaluate the magnitude of exposures to those directly associated with that practice and to those who provide nursing care to the patients containing radiopharmaceuticals. Exposure to members of the public are also addressed. The primary emphasis of this Report is on these individuals and not on the patient, since the patient receives the direct benefit from the nuclear medicine procedure. I t is recognized that the patient also receives the bulk of any potential radiation decrement. This Report was prepared by Scientific Committee 77 on Guidance on Occupational and Public Exposure Resulting from Diagnostic Nuclear Medicine Procedures. Serving on the Scientific Committee were:

Kenneth L. Miller, Chairman Pennsylvania State University Hershey, Pennsylvania Members

Frank P. Castronovo, Jr. Brigham & Women's Hospital Boston, Massachusetts

Martin L. Nusynowitz University of Texas Medical Branch at Galveston Galveston , Texas

Arnold P. Jacobson University of Michigan School of Public Health Ann Arbor, Michigan

Dennis D. Patton University of Arizona College of Medicine Tucson, Arizona

Sheila I. Kronenberger Stanford University Stanford, California Consultant

Edward W. Webster Massachusetts General Hospital Boston, Massachusetts

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PREFACE

NCRP Secretariat James A. Spahn, Jr., Senior Staff Scientist Cindy L. O'Brien, Editorial Assistant The Council wishes to express its appreciation to the Committee members for the time and effort devoted to the preparation of this Report. Charles B. Meinhold President

Contents .

1 Introduction ........................................................................ 1.1 Scope ................................................................................ 1.2 Quantities and Units .......................... ........................ 2 Public SigniGcance of Nuclear Medicine ..................... 2.1 Nature and Advantages .................................................. 2.2 Size and Growth .............................................................. 3 Radiation Risk in Perspective ........................................ 3.1 Introduction ..................................................................... 3.2 Risk ................................................................................ 3.3 Radiation Risks ............................................................... 3.3.1 Low-Level Radiation Doses ................................. 3.3.2 Dose Limits ........................................................... 3.3.3 Radiation Effects a t Low Doses .......................... 3.3.3.1 Hereditary Defects .................................. 3.3.3.2 Developmental Defects ........................... 3.3.3.3 Cancer Induction ..................................... 3.3.4 Comparative Risks ............................................... 4 Receipt and Delivery of Radioactive Materials ......... 4.1 Introduction .................................................................... 4.2 Shipment of Radioactive Sources ................................... 4.3 Receipt of Radionuclides ................................................. 4.4 "In-House" Transportation of Radioactive Materials ... 4.5 Transport of Patients ...................................................... 4.6 Transport of Specimens from Nuclear Medicine Patients ............................................................................ 5 Radiation Exposure from Nuclear Medicine Practice ................................................................................. 5.1 Nuclear Medicine Personnel Exposure .......................... 5.2 Radiation Doses to Patients and Persons Nearby and Members of the Public .................................................... 5.3 Exposure of Nurses and Other Medical Personnel ....... 5.4 Exposure of the General Public ..................................... 6 Radiopharmaceutical Handling Procedures in Nuclear Medicine ............................................................... 6.1 Introduction ..................................................................... 6.2 Radiopharmaceutical Dosage Preparation ....................

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CONTENTS

6.2.1 Commercial Radiopharmacy Unit Dosages ........ 6.2.2 "In-House" Radiopharmacy ................................. 6.2.3 Generators ............................................................ 6.2.4 Chemical Formulation ......................................... 6.2.5 Xenon .................................................................... 6.2.6 Nebulizers ............................................................. 6.2.7 Iodine (Diagnosis and Therapy) .......................... 6.3 Dosage Calibrations ...................................................... 6.4 Radiopharmaceutical Administration ............................ 6.5 Imaging ............................................................................ 6.6 Contamination Control ........ .......................................... 6.7 Misadministration ........................................................... 6.8 Safety Considerations with Nursing Mothers ............... 6.9 Radioactive Waste Disposal ............................................ 7 Radiation Safety Considerations for the Nursing

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Staff .......................................................................................

7.1 Radiopharmaceutical Administrations .......................... 7.2 Notification of Radiopharmaceutical Administration ... 7.3 When Radioactive Precautions Are Necessary ............. 7.3.1 The Patient ........................................................... 7.3.1.1 For Diagnostic Purposes ......................... 7.3.1.2 For Therapeutic Purposes ...................... 7.3.2 Collection and Handling of Excreta .................... 7.3.2.1 From Diagnostic Dosages ....................... 7.3.2.2 From Therapeutic Dosages .................... 7.3.3 Collected Specimens ............................................. Glossary .................................................................................... References ................................................................................. The NCRP ................................................................................ NCRP Publications .............................................................. Index .........................................................................................

1. Introduction 1.1 Scope

The medical use of unsealed radioactive materials, generally referred to as nuclear medicine, subjects four classes of persons to radiation exposure. These are patients, health care radiation workers, health care nonradiation workers, and members of the general public who are in the vicinity of these materials before, during or after their medical use. Considerations of patient exposure have been included in two previous reports of the National Council on Radiation Protection and Measurements (NCRP), namely NCRP Report No. 70, Nuclear Medicine-Factors Influencing the Choice and Use of Radionuclides in Diagnosis and Therapy (NCRP, 1982) and NCRP Report No. 73, Protection in Nuclear Medicine and Ultrasound Diagnostic Procedures in Children (NCRP, 1983). Estimates of the quantities of radionuclides administered to patients in nuclear medicine procedures together with evaluations of the equivalent dose to the gonads and effective dose, and their contribution to the population exposure and dose are included in NCRP Report No. 100, Exposure of the U.S. Population from Diagnostic Medical Radiation (NCRP, 1989a). A primary concern is the evaluation and control of occupational exposures to nuclear medicine and allied health personnel and to members of the public other than the patient. Since the general public would potentially receive exposure from patients containing radioactive material, t h e radiation levels close t o these patients are also important. Many groups of medical personnel may receive radiation exposure from radioactive materials used in medical practice. The principal groups are physicians, technologists, radiopharmacists and others who handle the radioactive material and radioactive waste or provide care for the nuclear medicine patient. In addition, other physicians, nurses, x-ray technologists, receiving room personnel, security staff, those who transport patients within the hospital, operating room staff, maintenance workers and others, may occasionally be exposed. Specific radiation protection guidelines for these and other allied health personnel have been given in NCRP Report No. 105, Radiation Protection for Medical and Allied Health Personnel (NCRP,

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1. INTRODUCTION

1989b). Members of the general public who might receive small exposures include other patients in waiting rooms, wards or multibed rooms, visitors and persons close to radioactive patients while in transit or in the home. Section 2 of this Report addresses the impact of nuclear medicine on the practice of medicine and on the diagnosis and treatment of disease. Its ability to image parts or organs of the body or, when necessary, the whole body and to treat cancers without performing surgery was a major public health accomplishment. The use of radioimmunoassay techniques was another major accomplishment that aided in a more complete understanding of diseases and disease processes. The advent of single photon emission computed tomography (SPECT) and positron emission tomography (PET) have added to the number and kind of nuclear medicine procedures being performed. Section 3 focuses on radiation risk and presents a few comparisons which will help to improve understanding of risk and provide some perspective on the importance of comparing risks of radiation exposure to other risks faced by our society. There is a brief discussion of limits of radiation exposure followed by an equally brief discussion of radiation effects. Section 4 traces the path of radioactive materials from receipt at a facility through delivery of the material to the nuclear medicine department, preparation of a dosage for administration to the patient, and dosage of the patient. Since, when the patient receives the radioactive material, he or she becomes a source of exposure to others, the patient is then followed through the facility. Another aspect examined is the movement of specimens from the patient to the laboratory for examination or testing. This may or may not represent another source of exposure. The subject of radiation exposure to individuals is further developed in Section 5. There are three principal sources to radiation workers-dosage preparation and assay, administration, and patient imaging or treatment. The details of each of these areas is analyzed and techniques useful to reduce exposures are examined. Finally, the exposure of those not involved in administration of radiopharmaceuticals to patients is examined. This group includes patients other than nuclear medicine patients who may walk through the halls or share a patient room, waiting room or elevator with a nuclear medicine patient, nurses or other providers of care to the patient, and members of the public. The more detailed examination of the handling procedures used in nuclear medicine are covered in Section 6. The two areas for preparation of dosages for administration to the patient are a

1.2 QUANTITIESANDUNITS

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commercial radiopharmacy or the nuclear medicine department. The exposures from these two sources and the advantages and disadvantages are discussed. The calibration and use of dosage calibrators are reviewed. The techniques of the administration of the radiopharmaceuticals to the patient by injection, inhalation or oral administration a r e reviewed. The subjects of contamination control, misadministration and safety consideration for nursing mothers are discussed. There is also a brief review of radioactive waste disposal. Section 7 treats the very important topic of radiation safety in the care of the hospitalized patient. These are generally patients who have received therapeutic amounts of radionuclides and, at least in the early times after administration, represent a significant source of exposure.

1.2 Quantities and Units In NCRP Report No. 116 (NCRP, 1993a),the NCRP recommended the use of a new quantity to be known as effective dose. By combining doses to radiosensitive organs in the body in a manner that accounts for their relative contributions to the total radiation detriment, the effective dose provides a single measure of dose that is directly related to detriment. The unit for this effective dose is sievert (Sv). Wherever in this Report the term dose is used, unless otherwise qualified, its meaning is effective dose. The energy absorbed per unit mass at a point in the human body exposed to radiation is known as the absorbed dose in tissue. The unit of absorbed dose is gray (Gy). For this Report, the quantity air kerma, and its special unit Gy, will be used in place of the quantity exposure. The two quantities are not interchangeable as the unit for air kerma is joules per kilogram and the unit for exposure is coulombs per kilogram. Since they are not interchangeable, the conventional unit name, roentgen, will not be used but, until such time as radiation detection and survey meters are calibrated in air kerma, the numerical value of exposure in roentgens may be assumed to be approximately equal to the numerical value of air kerma in rads, which is equal to air kerma in centigray. For a more complete discussion ofthese concepts see ICRU Reports 33 and 51 (ICRU, 1980; 1993) and for a more complete discussion of Systeme Internationale (SI) units see NCRP Report No. 82 (NCRP, 1985a).

2. Public Significance of Nuclear Medicine 2.1 Nature and Advantages Radiopharmaceuticals (drugs containing radionuclides) a r e administered to patients in order to make a physiologic measurement, to obtain images of organs or organ systems, or to provide treatment. Drugs or compounds tagged with specific radionuclides will deposit within the human body in a predictable manner (both as to location and amount). The advantages of using these techniques are that spatial distributions and physiologic behavior may be studied simply, noninvasively, a t low cost and withlow risk to the patient. As a n example, nuclear medicine imaging of the heart and studies of function are frequently used to provide information otherwise obtainable only by cardiac catheterization, an invasive procedure. The latter usually requires hospitalization and is accompanied by higher radiation dose, mortality, morbidity and cost. Another example is the determination of whether newly discovered breast cancer has metastasized (spread) to the bone. The nuclear bone imaging procedure is the most cost effective method available for making such a determination. If metastases in bone are found, they provide information important for developing a n appropriate treatment protocol for breast cancer. Numerous similar applications exist which illustrate the impact of this technology on clinical decision making in the management of patient problems. Although treatment (as distinct from diagnosis) with radiopharmaceuticals is a small part of the practice of nuclear medicine, it is very effective for certain medical conditions. The dosage administered for therapeutic purposes is 10 to 50 times the dosage administered for diagnostic purposes. The treatment of hyperthyroidism, (overactivity of the thyroid gland), is a routinely used procedure in nuclear medicine. In contrast, surgery requires hospitalization and has higher associated mortality, morbidity and expense. A third segment of nuclear medicine is radioimmunoassay laboratory testing. Such procedures do not require the administration of radioactive materials to the patient. In these tests, a biological

2.1 NATURE AND ADVANTAGES

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specimen, usually blood, is analyzed in the test tube usingradioactive materials for determination of the content of hormones. vitamins, drugs, enzymes, viral particles or products, cancer antigens or other chemicals. The methods are sensitive and precise and, since their advent a few decades ago, have revolutionized the understanding of disease and disease processes by the medical profession. These tests employ small quantities of radioactive materials and result in radiation exposures to the technologists involved in their performance that are so low the technologists need not be considered radiation workers, if that is their sole source of exposures. Information on the physical characteristics of commonly used radionuclides is set out in Table 2.1. The activity of radioactive materials used in diagnostic nuclear medicine examinations varies with the particular radionuclide employed and the purpose of the examination. In general, larger activities are used with radionuclides of shorter half-life. The range is from kBq for vitamin B-12absorption tests with 57Co(physical half-life 272 d) to GBq for PET studies of brain blood flow with 150(physical half-life, 2 min). Typical organ doses from diagnostic procedures are in the range of 10 to 30 mGy, and for therapy procedures, can exceed 100 Gy. In vitro radioimmunoassay procedures typically employ about 300 Bq of radioactive material. Since the tests are conducted in the laboratory on samples, e.g., blood, that have been removed from the patient, there is no accompanying radiation dose to the patient. Federal and state authorities have been involved in the regulation of nuclear medicine since its inception. All facilities responsible for medical use of by-product material must be licensed, for radionuclide use, by the U.S.Nuclear Regulatory Commission (NRC) or by an TABLE 2.1-Physical characteristics of radionuclides used in nuclear medicine. Radionuclide

Physical Half-Life

99mTc 6 h '=I 13 h la11 8d aolll 73 h 67Ga 78 h l%e 5.3 d "'In 68 h 82Rb 1.25 min l50 2.04 min llC 20.48 min 18F 109.74 min laN 9.97 min " k o m an unshielded point source in air. bFormrad h-I at 1 m from 1 mCi multiply by 0.037.

Air Kerma Rate Constant' (pGy h-I 100 MBq-I@ 1 mIb

2.0 3.8 5.5 1.2 4.0 1.1 3.4 16.7 15.7 15.7 15.1 15.7

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agreement state (see Glossary). For accelerator produced or naturally occurring radionuclides, many states regulate their use. Radiopharmaceuticals intended for medical use must be approved by the U.S. Food and Drug Administration. Major aspects of radiopharmaceutical production, transportation, application and disposal are regulated by various federal and state agencies.

2.2

Size and Growth

NCRP estimated in 1989 that about 100 million procedures using radioactive materials are performed each year in the United States for diagnostic and therapeutic medical purposes (NCRP, 1989a). Approximately 10percent of these procedures involve administration of radioactive pharmaceuticals directly to patients for diagnostic or therapeutic procedures. The remaining 90 percent are radioirnmunoassay procedures that involve the use of small amounts of radioactivity in analysis of patient urine, blood, etc. There are over 150 diagnostic and therapeutic nuclear medicine procedures involving the administration of radiopharmaceuticals to patients (AMA, 1991). According to a survey of full-time nuclear medicine clinics,' only 10 in vivo diagnostic procedures comprised over 90 percent of all such procedures performed in a typical nuclear medicine clinic, and only one therapeutic procedure constitutes the bulk of all nuclear medicine treatments. These results are qualitatively similar to those of Mettler et al. (1986) who showed that in the early 19809, nine categories of studies accounted for over 90 percent of diagnostic in vivo examinations (see Table 2.2). Witherspoon and Shuler2 obtained similar results in a survey of nuclear medicine facilities in the southwestern United States, but the distribution of studies has shifted significantly over the years. Cardiac and pulmonary nuclear medicine studies (pathophysiologic in nature) have doubled their share of total studies, whereas hepatic 94"T~ sulfur colloid imaging has disappeared from the top ten list. This change reflects two simultaneously occurring trends over the past decade. Radiologic imaging has significantly improved with the advent and application of high contrast, high resolution modalities (computed tomography, ultrasound, magnetic resonance imaging, 'Personal communications (1991) from Martin L.Nusynowitz, University of Texas Medical Branch at Galveston, Galveston, Texas. 2Unpublished survey (1991) from Lynn Witherspoon and Stanton Shuler of the Ochsner Clinic, Metairie, Louisiana.

2.2 SIZE AND GROWTH T

m 2.2-Relative

Procedure

Diagnostic Bone Gastric emptying Heart: Equilibrium radiocardiography Heart: Myocardial perfusion

Hepatobiliary Kidney

Relative Fkeauencv of Procedu&ss (percent)

740

1.3

40

0.2

110

4.5

mlT1thallous chloride 99"Tc sestamibi ""Tc teboroxime 99"Tcdisofenin 1311iodohippurate ""Tc pentetate *mTcmertiatide 99mTc macroaggregated albumin lS%e gas *Tc pentetate aerosol "31Na iodide '311Na iodide 99"Tc pertechnetate aG@ ' citrate

110 1,110 1,850

6.3 5.0 8.3

300 15 370 370 110

1.3 0.4 0.6 0.7 0.5

370 740

0.14 1.6

11.8

17.9 2.9

8.2

5.6 3.8 5.7

Activity Typical Administered Dose per Procedure to Patient (MBq) (mGy)

""Tc medronate or oxidmnate *Tc sulfur colloid *Tc red cells

4.6

7.3

Tumorlinfedion Other Therapeuticb Hyperthyroidism Thyroid cancer

Radiopharmaceutical

20.6

Lung ventilation

Thyroid (25% uptake of iodine)

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frequency of nuclear medicine procedures (1991), typical activities administered and typical dose.

9.6 Lung perfusion

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( {

{ {

15 4 185 190

0.4 0.7 0.7 13.0

1.8 I3lI Na iodide 740 0.2 '311Na iodide 3,700 "Based on an unpublished survey (1991)of nuclear medicine facilities by Martin L. Nusynowitz, University of Texas Medical Branch a t Galveston, Galveston, Texas. Treatment for hyperthyroidism and thyroid cancer estimated at 2 per 100 diagnostic procedures. 'Typical dose is meaningless in therapy. Dose to region of concern is the only consideration because that dose provides the benefit.

and digital subtraction angiography) for anatomic definition, thereby supplanting the poorer-resolution nuclear medicine techniques in the detection and definition of pathologic anatomy. On the other hand, pathophysiologically-oriented nuclear medicine studies have made significant progress with the availability of newer

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2. PUBLIC SIGNIFICANCE OF NUCLEAR MEDICINE

radiopharmaceuticals (e.g., myocardial perfusion agents, regional cerebral blood flow agents), instrumentation (e.g.,SPECT), and computers and software (e.g., renal function evaluation). The number of in vivo nuclear medicine examinations performed in hospitals in the United States increased about 16 percent from approximately 6.4 million to 7.4 million from 1980 to 1990 (Mettler et al., 1993). The projected growth rate of eight percent per year was not realized over this 10 y period mainly as a result of the virtual disappearance of 99"Tcpertechnetate brain scintigraphy and %Tc sulfur colloid liver imaging, which have been replaced by other modalities, such as computed tomography (CT) and magnetic resonance imaging. Meanwhile, nuclear cardiology studies have increased. As would be expected, the work load and procedure distribution a t any one facility depends, in large measure, on the size and nature of the facility, the patient population and on the interests of the medical community. Nevertheless, for all but small general hospitals, approximately 8 to 10 in vivo diagnostic studies on in- and outpatients are performed per year per occupied hospital bed. The relative frequency of performance of these procedures and typical amounts of radioactivity administered to a n adult are presented in Table 2.2. The coming decade will witness further changes as new procedures and techniques are developed and applied clinically. Likely to be among these are PET for the spatial mapping of functional parameters of the brain, including brain blood flow, metabolism, receptor activity, tumor metabolism and response to therapy, and cardiac flow and metabolism, using radiopharmaceuticals of the positron emitters "C, 150, 18F,82Rband 13N.Representative dosages and radiation absorbed doses (Kearfott, 1982a; 1982b) are listed in Table 2.3. TABLE2.3-Radiation absorbed dose for various PET studies (adapted from Kearfott, 1982a; 1982b). Radiopharmaceutical

Activity Administered

"CO C150

(MBq) 740 1,850

coi50

1,850

H ~ ~ ~ o 1,850 lBF-FDG 82Rb

370 1,850

Organ of Interest

Spleen, lungs, intestine Spleen, lungs, intestine Lungs Blood, kidneys, liver, lungs Bladder Heart, kidneys

Organ &sorbed Dose to Patient Absorbed Dose (pGy MBq-') (PGYMBg-')

14 to 23 4, 3, 4 1.3 3

5.0 0.4 0.4 0.4

120 3.5 to 5

10.5 0.4

3. Radiation Risk in Perspective 3.1 Introduction

The rapid growth in development and use of radiation and radioactive materials parallels the development of a large body of knowledge concerning the measurement of radiation, its interaction with matter, and its biological effects. Of special importance in connection with effects is the evidence that has been obtained from studies of human populations that have been exposed to radiation (ICRP, 1991a; 1991b; NCRP, 1993a; 1993b; UNSCEAR, 1993; 1994) There is much information and general agreement about risks following exposures to large radiation doses. In contrast, there is very little direct information about the effects on humans of low absorbed doses of radiation ((0.2 Gy) received by many radiation workers and the lower doses received by the public. The available data for humans do not allow direct estimates of risk from radiation doses below 0.2 Gy.

3.2 Risk

There is no such thing as a risk-free life. For most people, risk is an inherent and accepted part of daily life. Death is one risk we all face to some extent every day. The probability of death occurring ultimately in every person is unity. The risk from one source, exposure to radiation, should therefore be judged in comparison with the other risks which we face continuously throughout our lives.

3.3 Radiation Risks 3.3.1 Low-Level Radiation Doses

Numerous groups have estimated that medical radiation workers in the United States receive annual effective doses between 2.5 and

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5 mSv (NASNRC, 1980; UNSCEAR, 1988). Doses will vary with the individual and the task. Table 3.1 provides a summary of radiation doses routinely encountered by the public in various medically related procedures. It should be noted that the average annual dose to the public from nuclear power plants is <0.02 mSv. Also, for comparison, the annual effective dose from natural background radiation is on the order of 3 mSv (NCRP, 1987a).

3.3.2 Dose Limits The annual occupational dose limits for adults as adopted by the NRC beginning January 1, 1994, are 50 mSv total effective dose equivalent, 500 mSv for any individual organ or tissue other than the lens of the eye, 150 mSv for the lens of the eye and 500 mSv to the skin or any extremity (NRC, 1991). The limit on radiation dose, from licensed activities, for individual members of the general public is 1 mSv per y. (The natural background and exposure of patients for diagnostic or therapeutic purposes is excluded from these limits.) The guideline recommended by the NCRP (1993a) for the lifetime maximum accumulation of effective dose to occupationally exposed individuals is: cumulative lifetime limit = age in years x 10 mSv.

3.3.3 Radiation Effects at Low Doses Figure 3.1 summarizes the major events which follow energy absorption from ionizing radiations. The initial event is the absorption of energy from the radiation by the cells of the exposed person's body. This energy causes changes to occur in the molecules of protoplasm. Of all the possible molecular damage to irradiated cells, TABLE 3.1-Average annual effective dose equivalent received by members of the public as a result of various medically related activities in the United States (adapted from NCRP, 1 9 8 7 ~ ) . Average Annual Effective Dose Equivalent Source

Chest x ray CT (head and body) Diagnostic x rays Nuclear medicine procedures Transportation of radioactive materials "Per examination.

(mSv)

0.06" 1.108 0.40 0.14 0.0006

3.3 RADIATION RISKS

Energy Deposition

-

Bimhemical Changes

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Cellular ) Damage

I

r ) Cancer Induction Developmental (other cells)

Defects(Felal)

Giber Medical Effects(high doses only)

Fig.3.1. The major events which follow energy absorptionfrom ionizing radiation.

damage to DNA (the genetic material) is considered the most important (UNSCEAR, 1993). If the absorbed energy causes this chromosomal damage, two major results can occur: 1. if the damage occurs in the germ cells (in the ovaries or testes), hereditary defects in subsequent offspring or later descendants of the exposed person may result, and 2. if the damage occurs in body (somatic) cells of the exposed individual, it may result in one or more of the late somatic radiation effects. After exposure to radiation there is a theoretical increase in the probability of these effects. The late effects include mutagenic effects, teratogenic effects and cancer. Of course, repair or repopulation may mitigate effects. 3.3.3.1 Hereditary Defects. Radiation-induced inherited genetic effects have been observed in several animal species and in lower forms of life, but not in humans (NASNRC, 1990). The estimation of humangenetic risks is based mainly on data obtained in laboratory experiments using animals. The use of such data introduces the uncertainty of extrapolation from the laboratory conditions under which the experiments were conducted and the nature of the exposed animal to humans. Despite comprehensive studies of the children

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3. RADIATION RISK IN PERSPECTIVE

of the atomic-bomb survivors in Japan, there remains no evidence for heritable effects in humans (UNSCEAR, 1993). 3.3.3.2 Developmental Defects. Of the somatic effects of ionizing radiation other than cancer, developmental effects on the embryo or fetus are of greatest concern. High radiation doses can cause death, malformation, growth retardation and functional impairment. However, low doses k 0 . 2 Gy) do not appear, in general, to affect the developmental process. This observation suggests that there may be a threshold dose below which no effects occur. Threshold doses for some effects have, in fact, been demonstrated, but these thresholds vary for different abnormalities (NASLNRC, 1990). An exception to this generalization may be the recent observation of an increase in mental retardation among children irradiated in Hiroshima between weeks 8 and 15 of gestation. This risk appears to be proportional to dose a t the rate of 0.4 Gy-' (Otake and Schull, 1984)with a threshold for severe mental retardation of 0.1 to 0.2 Gy (NCRP, 1993a). [See also NCRP Commentary No. 9 with respect to exposure of the embryo, fetus and the nursing child (NCRP, 1994).1 3.3.3.3 Cancer Induction. There are data on cancer induction from high-dose exposures to certain human populations. These data can be used to estimate the degree of risk to be expected in a similar population exposed to smaller doses. Statistical methods are available for finding the expected number of cases required in order to have any chance of detecting an increased risk of cancer in an irradiated population compared to a suitable unirradiated control population. For example, based on riskestimates, Goss (1975)has estimated that for a dose to adults of 200 mGy and an observation time of a t least 20 y, [if there were a difference in cancer incidence (at the 95 percent confidence level)], an exposed population of 100,000 persons is required to detect that difference (Land, 1980;Webster, 1981). Similarly, at an equivalent dose of 200 mGy to the breast and an observation time of 20 y, a population of more than two million exposed persons and a similar number of unexposed individuals would be required to detect an increase in breast cancer if, in fact, one exists (Goss, 1975; Webster, 1981).The required population size must be even larger a t doses lower than 200 mGy. To determine radiation risk, a long observation period for detection is necessary due to the phenomenon of latency. For cancer induction by radiation, the latent period is the time between exposure to radiation and the onset of clinically detectable cancer. The minimum latent period is 10 y for all solid cancers except leukemia and bone cancers, in which the minimum latent period is 2 y (NCRP, 1993b).

3.3

RADIATION RISKS

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The latent period depends on: (1)methods of detection, (2) ease of examination, (3)role of cell division in tumor development, (4)degree of cell survival, ( 5 ) type of cancer, (6) dose to the organ of concern, and (7) age at exposure (UNSCEAR, 1993). Cancers arising in various organs and tissues are the principal late somatic effects of radiation exposure. As a very general guideline, the BEIR V Report (NASNRC, 1990) suggests a fatal cancer risk estimate of four cancers per 100 mSv in 1,000 exposed individuals. At the doses of 2.5 to 5 mSv experienced by nuclear medical personnel annually, the cancer risk is small. To place this in perspective, if an unexposed population of 1,000 persons was exposed to doses of 5 mSv y-l for 40 y there could be eight cancers in addition to the 210 cancer deaths that would occur in that population due to the normal incidence of cancer in the population of the United States. The dose limits recommended by NCRP, along with the practice of as low as reasonably achievable (ALARA),which has limited annual occupational doses to an average of 4 mSv or less (NASINRC, 1990), should limit any increased risk from radiation exposure in the work place. 3.3.4

Comparative Risks

Radiation protection philosophy is based on the conservative hypothesis that some risk is presumed to be associated with even small doses of ionizing radiation. The philosophy is based also on comparisons of radiation risks with other hazards of daily life, especially work hazards. However, in general, risks cannot be regarded as acceptable if they are readily avoidable or not accompanied by a commensurate benefit. The weighing of risks and benefits calls for personal value judgments, which can vary widely.

4. Receipt and Delivery of

Radioactive Materials 4.1 Introduction Following their manufacture, radiopharmaceuticals are handled several times before reaching their destination in nuclear medicine clinics and within other medical facilities. At each step, some radiation exposure may be incurred by the persons handling the package or the radiation source. In this Section the radiation exposure potential is considered during the following phases: delivery to and receipt within the medical facility, delivery to the end user, exposures in the course of radiopharmaceutical production and transportation, and transportation of radioactive specimens from a patient to the laboratory.

4.2 Shipment of Radioactive Sources Although a small number of accidents have occurred during the transportation of radioactive materials by common carrier, such accidents have produced no radiation-related injury and had little economic consequence (ANS, 1986). Transportation accidents involving even the highest levels of activity of radioactive materials used in generators, have been determined nuclear medicine, i.e., 99Mo-99mT~ to be accidents of a low-severity level (Dodd and Humphries, 1988). The radiological risk of transporting radioactive materials, in general, is low when compared to other nonradiological risks normally associated with transportation (Humphries and Dodd, 1989). Essentially all shipments of radioactive materials to medical institutions are transported either by air or land. Radiopharmaceuticals for diagnostic use usually have short half-lives and, unless the supplier is within a few hours driving distance of the institution, shipment is usually made by air. Numerous studies have been conducted to determine radiation exposure to air cargo workers (Bradley et al., 1977; Carter et al., 1982; Failla, 1977; Luszczynski et al., 1978;NRC,

4.4 TRANSPORTATION OF RADIOACTIVE MATEFUALS

1

15

1977;1978;Uselman and McKlveen, 1975).In normal circumstances, yearly maximum doses were found to be <5 mGy.

4.3 Receipt of Radionuclides

If radionuclides are packaged and shipped according to regulatory standards, the potential for inadvertent exposure is minimal. It is rare that a shipment has been improperly packaged or has suffered damage in shipping. However, it is imperative that, as soon as possible after receipt, all packages of radionuclides are examined and surveyed for contamination and radiation exposure and that the results are recorded in a log book according to an approved procedure (NRC, 1987).Typical dose equivalent rates at the surface and at 1 m from radiopharmaceutical packages upon receipt are indicated in Table 4.1.3

4.4 "In-House"Transportation of Radioactive Materials Table 4.1 indicates that the radiation level at the surface of certain packages can be substantial. Therefore, good radiation safety practice dictates that contact with the surface of these packages be avoided whenever possible and that "in-house" transportation be performed using carts. These carts can be shielded, but in most cases, the added distance from the source lessens the dose received by the operator and the public. The conveyance of radioactive materials for administration to the patient within the nuclear medicine department or within the hospital should present minimal radiation exposure potential provided appropriate shielding is employed. Typically, shielded containers with at least 3.2 mm lead equivalence are sufficient to absorb nearly TABLE4.1-Typical dose rates from radiopharmaceutical packages. Radioisatape

99Mo-9"T~generator 1251

1311

Activity (MBq)

At Surface (mGy h-I)

16,280 185 3,700

0.26 0.005 0.63

At 1 m (pGy h-')

0.8 (0.1 2.0

3Unpublished data (1985)from Kenneth L.Miller, Milton S. Hershey Medical Center, Hershey, Pennsylvania.

16

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4. RECEIPT AND DELIVERY OF RADIOACTIVE MATERIALS

all of the radiation emitted by radionuclides used in diagnostic nuclear medicine (see Table 4.2). For therapeutic amounts of 1311or positron-emitting radionuclides used in PET scanning, additional shielding is normally required. Shieldingshould be adequate to limit external radiation levels to no more than 20 p,Gy per h. For a 3,700 MBq source of 1311, the shielding required to reduce the dose rate at the surface of the shield to 20 p,Gy per h is approximately 5 cm of lead equivalence. It is again emphasized that the use of a cart, in addition to shielding, can greatly reduce radiation exposure during conveyance, and is particularly important for therapeutic quantities of high-energy gamma-ray emitters such as 1311.Assuming the diameter of the shielded container is 20 cm, the dose rate at 1m from its center is. about 100 times smaller than at the container surface. The transport of radioactive material in shielded containers is essential to reduce the exposure of individuals (the cart handler and members of the public).

4.5 Transport of Patients

The movement within a hospital of patients to whom radiopharmaceuticals have been administered for diagnostic purposes will normally present minimal potential for radiation exposure to those individuals near the patient. The radiation dose delivered to the TABLE 4.2-Shielding data for radionuclides used in nuclear medicine. Radionuclide

Major X- and GammaRay Energies, keV"

Half-Value Layerb in mm of Lead

27 (71%), 159 (83%)' 0.04 30 (38%),81 (37%) 0.2 7 1 (47%), 167 (11%) 0.23 140 (89%) 0.3 93 (38%), 184 (21%), 300 (17%) 0.66 364 (81%) 3.0 23 (68%),171 (91%),245 (94%) 1.3 511 (192%), 777 (13%) 6.0 150 511 (200%) 5.5 C 511 (200%) 5.5 IBF 511 (194%) 5.0 13N 511 (200%) 5.5 "Emissiondata abstracted from NCRP (1985b). general, the use of 10 half-value layers will reduce the intensity to 1,000th the unshielded value. 'Percent ( indicates I ) number of gamma rays per 100 disintegrations. 1231

135Xe nrlTl 99mTc 67Ga 1311 lI1In 82Rb

"

4.6 TRANSPORT OF SPECIMENS

1

17

patient following the administration of a radiopharmaceutical is determined by the physical characteristics of the radionuclide, the biological characteristics of the pharmaceutical, and by the activity administered. The dose received by a person nearby is influenced also by the exposure time and the distance from the patient. Although the radiation dose rate a t 1m from a typical diagnostic patient is usually about 10 kGy per h (Pennock et al., 1980), the same cannot be said of the patient to whom a therapeutic quantity of radionuclide is administered (Castronovo et al., 1982a; Miller et al., 1979; Pennock et al., 1980; Vanderlick et al., 1980). For example, the dose rate at 1m from a patient immediately after administration of 3,700 MBq of 1311will be approximately 0.2 mGy per h. Some of these patients may experience nausea and vomiting following the administration of the radiopharmaceutical. Therefore, to minimize the potential for contamination and exposure, it is preferable if large quantities (>1,000 MBq) of therapeutic radiopharmaceuticals are administered in the patient's room.

4.6 Transport of Specimens from

Nuclear Medicine Patients Table 4.3 provides information on the dose rate from blood samples pertinent to routinely used radionuclides and nuclear medicine procedures. It is evident that the maximum activities in a sample of blood taken after a short equilibrium period, as well as the dose rates at the surface of the test tubes, are minimal in most cases. The highest maximum dose rate in Table 4.3 is for thevery unlikely case of a blood sample taken from a patient within 1h after the administration of the usual amount of 1311 used for thyroid cancer treatment. Compare this 25 p,Gy per min with a derived occupational dose rate to the fingers of 10 mGy per week, i.e., the maximum weekly finger dose would be received handling a test tube containing the sample for 6.7 h. The dose rates for blood samples taken from patients receiving diagnostic tests are 30 or more times lower and are usually negligible compared to those from therapy patients. Doses received when handling blood samples containing radionuclides can be reduced readily by a factor of three or more through the simple practice of holding the test tube a t the top above the level of the blood in the tube. It is not necessary to shield blood samples unless a large number are accumulated in one spot. Also, it is not necessary to provide personnel monitoring for individuals handling such samples. There

18

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4. RECEIPT AND DELIVERY OF RADIOACTIVE MATERIALS

TABLE4.3-Dose rate from blood samples withdrawn following injection of radiopharmaceuticals for common nuclear medicine p r o ~ d u r e s . " ~ Maximum Activity Maximum Dose Rate Procedure

Diagnostic Bone (WC) Kidney (9hTc) Thyroid P T c ) Thyroid ('?I) Cardiac (9"Tc) Abscess/tumor (67Ga) Lung perfusion (=Tc) Therapeutic Hyperthyroidisme ("'I) Thyroid canceP ("'I)

"q Admlnlsted

in 10 ml Bloodc

(MBq)

a t 1crnd (pGy min-'1

740 370 185 15 1,110 190 110

1.3 0.7 0.3 0.1 2.0 0.3 0.2

1.6 0.8 0.4 <0.2 2.4 0.6 0.2

740 3,700

1.33 6.66

5.0 25.0

"One minute after injection. bRadiopharmaceutical administered a s in Table 2.2. 'Based on 5,500 ml total blood volume. dAssumes 1 cm distance to fingers from 6 cm line source. 'Following absorption into the blood.

is a slight potential for an individual to become contaminated. However, universal precautions, e.g., avoiding contact with fluids, wearing gloves and cleaning up spills immediately, should eliminate this potential problem. It is good practice to tag, or otherwise label as radioactive, samples from therapy patients so that subsequent handlers are aware of the radioactivity and can assure that radioactivity from the patient does not interfere with radioimmunoassay results.

5. Radiation Exposure from Nuclear Medicine Practice 5.1 Nuclear Medicine Personnel Exposure

Exposure of nuclear medicine personnel to radiation can arise from three main activities: dosage preparation and assay, injection, and patient imaging. The dose received from dosage preparation is variable, depending on the particular procedure, and is of the order of 0.2 kGy per dosage preparation (NCRP, 1990). Typical doses to personnel engaged in preparation and assay in the clinical situation are in the range of 5 to 6 mGy y-l, and the use of central radiopharmacy facilities tends to reduce doses to personnel engaged in injection and imaging. A survey by Iyer and Dhond (1980) indicated that doses averaged 1.95 mGy per 1,000 procedures for personnel in clinics where the radiopharmacy was supplied versus 3.42 mGy per 1,000 procedures where the technologists eluted generators and prepared the radiopharmaceuticals in addition to their other activities. Batchelor et al.(1991) and Williams et aL.(1987) have indicated an average annual potential dose to the extremities of nuclear medicine technologists of 118 mGy and maximum doses approaching the annual limit of 500 mGy. This dose varies depending on the numbers and kinds of procedures performed, the use of available shielding devices and the caution exercised in handling and administering the radiopharmaceutical. Also of concern is the potential for doses to the fingers from contamination. Barrall and Smith (1976) indicated doses of up to 100 Gy for a point source of 37 kBq of mTc on the skin. Newer estimates reported by Kereiakes (1992) indicate the dose a t closer to 200 Gy for a point source on the skin that is allowed to remain until total decay. If the activity is spread over 1cm2the resulting dose would be several orders of magnitude lower (Faw, 1992) and more on the order of 0.07 Gy if allowed to remain until total decay (Kereiakes, 1992). The unit dosage is administered to the patient, usually intravenously, using a shielded syringe. Other routes of administration include intrathecally, orally, by inhalation, by instillation into the

20

1

5. RADIATION EXPOSURE FROM NUCLEAR MEDICINE

eyes, bladder or rectum, or into body cavities (peritoneal, pleural or pericardial cavities). The administration is usually performed in an "injection" area in the nuclear medicine department, but it is done sometimes in the patient's room. After administration, the patient may be studied almost immediately, or the study may be delayed several hours or several days depending upon the procedure. During this delay an inpatient may be returned to bed, while an outpatient may occupy a waiting room or resume ordinary activities while waiting for the study to commence. In the former case, hospital personnel (e.g.,nurses, transporters) receive some exposure; in the latter case, other patients, hospital employees and members of the general public are exposed (see Sections 5.2, 5.3 and 5.4). The remaining components of dose received by nuclear medicine personnel are due to their proximity to the patient for positioning of the patient and performance of the imaging procedure. Typically these operations contribute up to 8 mGy per y for the nuclear medicine technologist (Ahluwalia et al., 1981;Barrall and Smith, 1976; NCRP, 1990)(see Section 6.5). Upon completion of the study, patients are returned to rooms or wards, or they leave for their homes and work places where other medical workers (nurses, hospital personnel) and other patients or the general public, including families, are exposed to the radiation emitted by the patient.

5.2 Radiation Doses to Patients and Persons Nearby and Members of the Public The dose to a patient following the administration of a radiopharmaceutical is determined by the physical characteristics of the radionuclide, the physiological specificity of the pharmaceutical and the amount of radioactivity administered. The dose received by a person nearby is influenced by these same factors, but is determined by the exposure time and distance from the patient. The dose received by a person near the patient will be much smaller than that received by the patient because the exposure time is typically only minutes to hours, the radiation is partially absorbed by the patient's body and distance from the patient lowers the dose rate. The amount of radioactivity in the patient is gradually reduced by its physical decay and by excretion primarily in the urine or feces, and therefore, the dose rate to both patient and those nearby will

5.3 EXPOSURE OF NUFLSES AND OTHER MEDICAL PERSONNEL

1

21

fall with time. Table 5.1 provides radiation dose rate information for 99"TcMDP patients from the time of injection to 24 h after injection (Castronovo, 1991). Table 5.2 lists the dose at skin surface, 0.5 m and 1m from a patient receiving the procedures listed in Table 2.2. This is the maximum dose that could possibly be received by an individual remaining at the distance specified until there is total decay of the radionuclide in the patient.

5.3 Exposure of Nurses and Other Medical Personnel Although nuclear medicine procedures contribute approximately 15 percent of the average dose to the United States population (NCRP, 1989a) this is essentially all exposure to the patients undergoing the procedures and deriving benefit from the exposure. The report of the Committee on the Biological Effects of Ionizing Radiations [BEIR I11 (NASNRC, 1980)l indicates that the film badges of 40 percent of monitored hospital personnel indicate undetectable doses, and, as measured individual doses increase, the number of exposed individuals decreases in an exponential fashion. The average dose for medical personnel performing x-ray and nuclear medicine procedures is somewhere in the range of 3 to 5 mGy per y. There is some indication that the dose for nuclear medicine personnel may currently be lower than this average (Miller, 1990). A study by Hendee and Edwards (1990) found that approximately 53 percent of those occupationally exposed in medicine receive less than a TABLE5.1-Dose rates from patients injected with 740 MBq 99mTcMDP. Time After Injection

5 min

Patient

-

Patients with and without bone metastases

Number of Patients

Surface Projections" (mGy h-'1

-

16 anterior posterior 16 right 10 left 10 4h Without bone 9 anterior metastases 9 posterior 7 anterior With bone metastases 7 posterior Without bone 9 anterior 24 h metastases 9 posterior With bone 7 anterior metastases 7 posterior "Survey meter a t patient's waist level. bBackgroundlevel.

0.09 0.09 0.05 0.06 0.03 0.05 0.14 0.49 0.01 0.005 0.02 0.05

30.5 an (mGy h-')

1m (mGy h-'1

0.03 0.04 0.02 0.02 0.01 0.02 0.06 0.17 0.0007 0.001 0.003 0.009

0.009 0.01 0.01 0.01 0.003 0.006 0.02 0.04 -b

-b -b -b

22

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5. RADIATION EXPOSURE FROM NUCLEAR MEDICINE

TABLE5.2-Common nuclear medicine procedures, patient doses and calculated external dose at selected distances.

Procedure

Diagnostic Bone Gastric emptying Heart: Equilibrium radiocardiography Heart: Myocardial perfusion Hepatobiliary Kidney

Lung perfusion Lung ventilation Thyroid (25% uptake of iodine) Tumorfinfedion

Radiopharmaceutical

%Tc medronate or oxidronate -Tc sulfur colloid *Tc red cells "IT1 thallus chloride *Tc sestamibi -Tc teboroxime -Tc disofenin "'I iodohippurate %Tc penetate %Tc mertiatide -Tc macroaggregated albumin 13%e gas T c pentetate aerosol lBI Na iodide "'I Na iodide -Tc pertechnetate 'j7Ga gallium citrate

Hyperthyroidism 13'1 Na iodide Thyroid cancer 1311Na iodide aFor patient dose see Table 2.2. bFrom surface of patient.

Patient Skin Dose Dose to Total Surface to Total Decay at Decay at Dose 0.5 mb(@Gy) 1.0mb(@Gy) (mGyY

0.5

42

14

0.1 1.7

7 146

3 48

2.6 1.9 3.1 0.5

204 162 269 42

67 54 89 14

0.2 0.2 0.3 0.2

13 19 23 15

4 6 7 5

0.1 0.6 0.1 0.3 0.3 4.9

5 52 11 23 23 42 1

1 17 4 7 7 139

15.7 78.7

1,361 6,803

450 2,249

measurable exposure and the majority, approximately 88 percent, receive <1 mGy per y. They also found that fluoroscopy was the medical procedure most responsible for the higher occupational exposures. Hospital personnel who have only occasional contact with nuclear medicine patients receive only a fraction of the dose received by the nuclear medicine personnel who handle the patients as well as the radioactive materials and tagged radiopharmaceuticals that are used in diagnosis and treatment of these patients. As can be seen from Table 5.3, non-nuclear medicine personnel's dose from the nuclear medicine patient is expected to be only a small percentage of that received by the nuclear medicine technical personnel. The NCRP (1989a1 indicates that most hospital employees are not

5.4 EXPOSURE OF THE GENERAL PUBLIC

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TABLE5.3-Estimated dose of persons exposed to nuclear medicine patients. Dose

Dose

wr Procedure

wr Year (PGY)

(PGY)

Patient whole-body dose Nuclear medicine technical personnel Non-nuclear medicine hospital personnel Family members Co-workers General public (per capita) Trom Benedetto et a2. (1989).

4,400 20" 7"

-

4,000 100

0.4"

considered to be occupationally exposed workers, meaning their potential for exposure is quite low (less than 10 percent of the occupational dose limit). As previously indicated, the exposure from diagnostic nuclear medicine patients is typically <0.01 mGy h-I at 1m from the patient. The short amount of time normally required to attend to these patients, results in total doses to hospital personnel that are low. There might be situations that deviate from this that require evaluation by survey and personnel monitoring, e.g., nursing care for high activity radioiodine thyroid cancer patients. In general, personnel monitoring along with training in good radiation safety practice and adherence to radiation safety protocols, such as those described in NCRP (198913) will be adequate to keep the exposure of hospital personnel fi-om nuclear medicine patients to acceptably low levels.

5.4

Exposure of the General Public

The potential exposure of nuclear medicine and other hospital personnel to radiation fiom nuclear medicine patients is low. Therefore, the potential for exposure to members of the public from these patients must be lower. Pennock et al. (1980)estimated the exposure to members of the public from diagnostic nuclear medicine patients. Assuming that an individual remained at a distance of 1m from the patient from the time of injection until the radionuclide had decayed, Pennock et al. calculated doses resulting fiom these exposures ranging from a few p.Gy to 0.21 mGy. A more realistic approach assumed that the individual remained at a distance of 1 m for the entire first hour after injection. In this second situation, the doses were considerably lower than the doses calculated for the extreme situation and represented only a small portion of the radiation received annually from natural background radiation.

24

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5. RADIATION EXPOSURE FROM NUCLEAR MEDICINE

Benedetto et al. (1989) measured the dose rate a t the abdominal skin surface of outpatients receiving a variety of radiopharmaceuticals in order to estimate the population dose from nuclear medicine studies. They found that for exposure of co-workers and family, doses were 7 and 20 pGy per procedure, respectively, for the selected radiopharmaceuticals (see Table 5.3). Doses per procedure to nurses, orderlies, transporters, etc., would be somewhat less than these values because of shorter exposure times and their total annual effective dose would be less than that of nuclear medicine technical personnel. Approximately 10 million patient procedures are performed yearly. A,conservative dose to a member of the general public of 10 pGy per procedure is assumed for a population of 250 million and the average dose from nuclear medicine patients is calculated to be 0.4 pGy per person per y. Table 5.3 summarizes the results described in this Section.

6. Radiopharmaceutical Handling Procedures in Nuclear Medicine 6.1 Introduction In nuclear medicine there are various procedures that require direct handling of radioactive materials. These include compounding and dispensing in a radiopharmacy, calibration of stock vials and dosages for administration, and administration to the patient for diagnosis or therapy. Each of these procedures, from receipt to administration, represents the potential for contamination and exposure of the nuclear medicine department staff. Following administration, the patient is also a potential source of exposure and contamination. These procedures and steps taken to control exposure and contamination are presented in this Section.

6.2 Radiophamnaceutical Dosage Preparation

Radionuclides for patient dosages may be received by the nuclear medicine department from a commercial radiopharmacy or from an internal (hospital) radiopharmacy as "unit doses," i.e., the dosage for a single patient (unit dose), as generator eluates (see Glossary), or as multidose radiopharmaceuticals.

6.2.1 Commercial Radiopharmacy Unit Dosages The commercial radiopharmacy obtains radionuclides in large quantities, elutes generators, compounds various chemical forms, conducts quality-assurance procedures, and prepares prescribed dosages for delivery to nuclear medicine departments within its geographical area. The most commonly supplied unit dosages are indicated in Table 2.2. The unit dosages are precalibrated solutions in individual shielded syringes or in capsules (1231,1311).

26 6.2.2

/

6. RADIOPHARMACEUTICAL HANDLING PROCEDURES

'Yn-House" Radiopharmacy

"In-house" radiopharmacies perform the same function as commercial radiopharmacies, but on a smaller scale. The commercial pharmacies are likely to have more elaborate shielding, additional remote handling devices, and more complex techniques than the nuclear medicine department. In one study (Ahluwaliaet al., 1981),the mean quarterly dose per nuclear medicine technologist was reduced from 2.0 mGy to 0.70 mGy when unit dosages were received from the commercial radiopharmacy; or a reduction of dose per person from 4.5 kGy per unit dosage to 1.2 hGy. The reduction of 3.3 kGy per person per unit dosage is due to the elimination of generator elution and unit dosage preparation in the nuclear medicine department. 6.2.3

Generators

A generator consists of a parent radionuclide adsorbed on a column from which a shorter-lived decay product is eluted by passing a suitable solvent (or air in gaseous generators) through the column. Additional shielding placed around the generator after receipt from the supplier is usually required to reduce personnel exposure, particularly ifit is located in a small, crowded area. Elution of the generator has a potential for contamination due to release of droplets of the eluate upon removal of the collection vial. Nuclear medicine personnel must follow rigid precautions as described in the package.insert that accompanies generators. Failure to do so can lead to less than optimal yields, significant personnel contamination, and unnecessary exposure. 6.2.4

Chemical Formulation

Some radiopharmaceuticals are administered in the chemical form in which they are received, and may require only a volume adjustment to obtain the correct patient dosage as measured with a dose calibrator. Examples are sodium 1311iodide, ZOITlchloride and "Ga citrate. Capsules of sodium lZ3Iiodide are administered as received. Most radiopharmaceuticals require only minimal formulation such as the addition of 99mTc pertechnetate (eluted from the generator or received from a radiopharmacy) to a shielded commercial kit vial of reactants, e.g., methylene disphosphonate (MDP), oxidronate and pyrophosphate, and mixing or shaking of the contents. Some radiopharmaceuticals require more extensive handling. One method of preparation of 99"Tc sulfur colloid requires the vial containing the

6.2 RADIOPHARMACEUTICAL DOSAGE PREPARATION

1

27

reaction mixture to be boiled in a water bath. To reduce external exposure, the water bath should be shielded. Contamination by airborne release may occur if the water bath is allowed to boil dry and the vial ruptures. An example of a complex formulation is the preparation of lilIn labeled white cells. The ll1Inrequires extensive handling while labeling the separated white cells from a patient's blood. Reaction vials, tubes and syringes should be shielded to reduce external exposure, and care should be taken to avoid contamination of the work area during transfers of active material, particularly in view of the 67 h physical half-life of lllIn. Measurements of personnel exposures have indicated receipt of doses of 3.8 pGy during cell labeling for a 100 MBq dosage. Because a large hospital may perform 100 to 200 such procedures per year, the cumulative dose to radiopharmacy personnel from these procedures could reach 0.5 mSv per y.4 The annual occupational dose limit is 50 mSv (NCRP, 1993a). In preparing unit dosages, excessive external exposure can occur unless shielding is provided for both the stock vial and the syringe to be used for administration of the radiopharmaceutical. Exposure rates up to 200 mGy h-l have been measured a t the surface of unshielded syringes containing 740 MBq of 99mTc.However, if a syringe shield is used, the exposure rate is reduced by a factor of about 50 (Barrall and Smith, 1976).

Xenon-133 is available in a unit dosage gaseous form requiring special storage and transfer devices. Shielded 133Xetraps containing effluent air contamination monitors are available commercially. Releases to the atmosphere should be known so that exposures can be controlled by replacing the traps and so that derived reference air concentrations (DRACs) are not exceeded (NCRP, 1993a). In addition, because of adsorption of the xenon from the saline onto the syringe barrel and plunger, as much as 45 percent of the dosage may remain in the syringe after delivery if the syringe is stored for 6 h after initially drawing up the dosage, and 60 percent can remain if the storage time is 24 h. Therefore, the "empty" syringe, if unshielded, is a potential source of external exposure to nuclear medicine personnel. For these reasons all xenon containers, both pre- and post-administration, should be stored in a well-ventilated Wnpublished data (1982) from Sheila I. Smith, Stanford University (WHO24 Hazards Evaluation), Stanford, California.

28

1

6. RADIOPHARMACEUTICAL HANDLING PROCEDURES

fume hood to avoid exceeding the DRAG of 13%efor controlled areas (also see Sections 6.4 and 6.5). 6.2.6

Nebulizers

One technique for visualizing the lungs involves inhalation by the patient of a mist (aerosol) generated by nebulizing mTc DTPA. Although the patient inhales from 75 to 185 MBq (McGraw et al., 19921, the nebulizer typically contains 740 to 1,100 MBq of *Tc DTPA and must be carefully shielded. Widespread contamination can occur (McGraw et al., 1992) by inadvertent misassembly of the nebulizer which can result in the venting to the air of appreciable quantities of the 99"TcDTPA. Care must be taken to assemble the nebulizer according to the manufacturer's instruction. Also, care must be taken to ensure that techniques are used that will minimize airborne contamination and worker dose (Crawford et al., 1992). 6.2.7

Iodine (Diagnosis and Therapy)

Radioactive iodine has been noted for its volatility and therefore its potential for causing internal radiation dose in nuclear medicine personnel. Early (1987) and Miller et al. (1979) reported that two to three percent of the liquid 1311activity escaped when the cap of the bottle ofliquid oral solution was removed as compared to 0.01 percent of the activity lost for iodine in capsular form. Carey and Swanson (19791, Jackson and MacIntyre (1979), and Luckett and Stotler (1980) have investigated the effect of increased pH, buffers, antioxidants and stabilizers in reducing the radioiodine volatilization. Solutions of sodium iodide (Na1311)for therapeutic use are now available as a stabilized aqueous solution. Miller and Erdman5have measured volatilized activities ranging from 0.15 to 0.36 percent with liquid solutions listed as "stabilized." Therefore, prior to administration, the radioactive iodine solution vial should be uncapped and vented (Early, 1987) in a fume hood (preferably with an activated charcoal filter) for a few minutes to remove any iodine present in the vial air space. The vial should then be recapped, the activity measured in a dosage calibrator and transported to the patient for administration. The hospital room used for therapy patients should be prepared for contamination control by covering objects and areas potentially a t 'Unpublished data (1992)from Kenneth L. Miller and Michael C. Erdman collected at Milton S. Hershey Medical Center, Hershey, Pennsylvania.

6.3 DOSAGE CALIBRATIONS

/

29

risk such as night stands, the telephone mouthpiece, television controls, toilet areas, light switches, etc., with plastic or absorbent paper (Miller et al., 1979). Disposable eating utensils should be treated as radioactive waste and the linens should be monitored prior to releases to the general laundry. Safety guidelines for the release of radioactive patients from the hospital have been issued (NCRP, 1970; 1995; NRC, 1994a; 1994b). For radioiodine therapy patients these guidelines consider the potential exposure to family members and members of the public from the discharged patient and provide guidelines for the patient to minimize exposure to family members and members of the public. Jacobson et al. (1978) measured dose rates to family members from released radioiodine patients ranging from 1.7 p,Gy d-l to 1.3 mGy d-' and thyroid dose equivalents from uptake by family members that ranged from 0.04 mGy to 13.3 mGy. Federal regulations (NRC, 1992a) permit 1311 therapy patients to be discharged when the exposure rate from the patient is lower than 0.05 mGy h1a t 1m or the residual activity is below 1,110 MBq. However, a proposed change to the regulation recommends a release criteria of 5 mGy in any 1y and eliminates the 1,110 MBq criteria (NRC, 1994b). Although the regulations indicate the patient can be released a t or below these levels, they do not say that the patient must be released a t this level. The nuclear medicine physician should consider the home situation, i.e., the exposure of family members after the patient is released and the radiation safety precautions to be issued to the patient upon discharge [see NCRP Commentary No. 11(NCRP, 1995) for further information].

6.3 Dosage Calibrations The activity of radiopharmaceuticals must be measured prior to administration to the patient. This is done in a dosage calibrator by removing the syringe containing the dosage from its syringe shield and placingit in the chamber ofthe calibrator. The calibrator controls are set to the radionuclide involved and the activity is shown andl or printed out automatically. The unshielded syringe is then removed from the chamber and replaced in the syringe shield. Gloves should be worn to avoid contaminating hands if the syringe is handled directly. Tongs should be used to both place and remove the syringe to avoid excessive exposure. Also, the dosage calibrator must be periodically calibrated (NRC, 1987) and checked daily with reference sources. These reference

30

6. RADIOPHARMACEUTICAL HANDLING PROCEDURES

sources should be shielded when not in use and handled with tongs to minimize exposure.

6.4 RadiopharmaceuticalAdministration Care must be taken during dosage administration to prevent contamination and undue exposure. A dosage administration area is usually set aside in the nuclear medicine clinic for those patients who are ambulatory. For those patients who are not ambulatory, the dosage is administered to the patient on the gurney, or on the imaging table, or in their hospital room if the study requires appreciable delays before imaging. In order to minimize exposure, the radiopharmaceutical should be taken to the patient in a shielded syringe in a lead transport container. Both the dosage administration area and the technologist's hands should be monitored for contamination immediately after administration of the radiopharmaceutical. Any radioactive waste that is generated during the dosage administration process, including the empty syringe, should be put into a shielded radioactive waste container. (See Section 6.6 for procedures to follow if contamination is detected.)

6.5 Imaging

Most imaging is performed in the nuclear medicine department. However, for certain patients, such as those in intensive care units, t h e imaging is performed in the patient's room using portable imaging systems. Following injection, the patient is a source of external exposure and, during imaging, individuals should maintain a reasonable distance from the patient. Radiation exposure rates a t the edge of imaging tables have been measured as 0.2 mGy h-l from 59.2 MBq 'OIT1 chloride, 0.015 mGy h-' from 185 MBq 99mTcHSA MDP (human serum albumin) and 0.025 mGy h-Ifrom 740 MBq 99mTc (Syed et al., 1982).

6.6 Contamination Control Numerous studies (Barrall and Smith, 1976; Crawford et al., 1992; Early, 1987; Jackson and MacIntyre, 1979; Luckett and Stotler, 1980; Miller et al., 1979; Nishiyama and Lukes, 1982; Nishiyama

6.6 CONTAMINATION CONTROL

1

31

et al., 1980; Serrano et al., 1991)have indicated significant potential for contamination of air, surfaces and personnel as a result of nuclear medicine practices. These findings re-emphasize the importance of conducting such activities in a manner that minimizes the potential for contamination, detects and removes contamination immediately when it happens, and identifies effective methods to prevent or minimize the possibility of a recurrence. Routine and frequent monitoring of all activities that can lead to contamination is essential. There are three areas that require particular attention:

1. Air. Exposure to airborne contamination from procedures, such as radioiodine diagnosis and therapy, the use of aerosols and the use of radioactive inert gases can lead to intake and exposure. Each of these procedures must be carefully evaluated to ensure that the risk of exposure is minimal. The procedures used by personnel should be routinely evaluated to identify slippage or inadvertent change from good safety practice (NRC, 1987; 1992b). Deficiencies should be corrected immediately. Incidents that lead to contamination or exposure should be investigated and corrected immediately and evaluated to see if changes can be made that will minimize the likelihood of recurrence. 2. Surfaces. Surface contamination can occur easily and unexpectedly in nuclear medicine. Areas such as those used for dosage preparation, calibration and administration routinely become contaminated and require frequent radiation protection surveys (NRC, 1987). Other areas such as imaging rooms, waste storage areas, patient waiting areas and corridors also need to be monitored routinely. The areas with a high potential for contamination should be surveyed for contamination after each procedure that could lead to contamination and at the end of each day. Areas with lower potential for contamination can be surveyed after each procedure or on a weekly basis. In general, the frequency with which contamination is found will indicate the frequency of required surveying. 3. Personnel. Contamination of personnel employed in nuclear medicine can occur frequently and unexpectedly. Although the hands are the most likely area to become contaminated, any part of the body and the clothing is a t risk. Skin contamination can lead to external exposures, and can be a source of internal exposure through ingestion and skin absorption (Miller et al., 1985). Therefore, monitoring of the hands after each radionuclide handling procedure is a necessary radiation safety practice

32

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6. RADIOPHARMACEUTICAL HANDLING PROCEDURES

(NRC, 1987).The remainder of the body, including shoes, should be monitored frequently and especially before leaving the nuclear medicine area. Prompt attention must be given to any incident that leads to contamination in nuclear medicine so that corrective procedures can be instituted and personnel exposure evaluations can be performed. In the event that such contamination could have led to internal contamination, appropriate bioassay should be performed to assess the internal dose (NCRP, 1987b; NRC, 1991).

6.7 Misadministration The misadministration of radiopharmaceuticals to patients causes unnecessary exposure and subjects the patient to risk of injury, especially in the case of therapeutic misadministration. The misadministration rate in nuclear medicine is low, approximately 1 per 10,000 procedures (NCRP, 1991).It has been estimated that diagnostic misadministration represented less than 0.04 percent of the total effective dose of 32,100 person-Sv for all diagnostic nuclear medicine procedures performed in 1982 (NCRP, 1991).When amisadministration occurs, an immediate investigation should be initiated to discover the cause, to estimate the dose, to take the steps necessary to prevent its recurrence, and to provide appropriate counseling of the patient and the patient's referring physician. Recent NRC regulations have redefined the term "misadministration" and have added a new classification, "recordable event" (NRC, 1992a).

6.8 Safety Considerations with Nursing Mothers Various radionuclides, including most used i n nuclear medicine practice, will concentrate in the milk of lactating females (Assimakopoulos et al., 1989; Dydek and Blue, 1988; Gattavecchia et al., 1989;Hedrick et al., 1986; 1989; Mountford et al., 1984; NCRP, 1994; Ogunleye, 1983; Pittard et al., 1982; Romney et al., 1989; Rubow and Klopper, 1988; Rumble et al., 1978; Sharma et al., 1984; Siddiqui, 1979). The length of time that this source of radioactivity poses an exposure potential for a nursing infant depends on the effective half-life of the radiopharmaceutical. The chemical form and the radionuclide should be taken into consideration by the nuclear medicine physician in counseling the nursing mother. With ""Tc

6.9

RADIOACTIVE WASTE DISPOSAL

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33

tagged compounds, breast feeding can usually resume within a few to 72 h ; whereas, with therapeutic radionuclides, such a s "P and 1311 the period is extensive and might warrant cessation of nursing. In addition to the exposure potential from radionuclides excreted in milk, there exists a potential for exposure to infants held in close contact with a patient who has undergone a nuclear medicine procedure (Mountford, 1987; Mountford et al., 1991; NCRP, 1994). This exposure pathway is especially important for patients who have been administered therapeutic dosages. The nuclear medicine physician should consider this contact dose potential when counseling the patient. Because evidence suggests that infants may be somewhat more sensitive to radiation than adults, radionuclide therapy patients should be counseled to take a conservative approach in handling or interacting with infants (NCRP, 1993b; 1994). [See NCRP Commentary No. 9 (NCRP, 1994) for a discussion on protecting the embryo, fetus or nursing child.]

6.9 Radioactive Waste Disposal Nuclear medicine departments generate low-level radioactive waste, mostly of the dry type, in the form of empty vials, syringes, disposable gloves, absorbent paper, gauze pads, items from therapy patient care (bed linens, disposable eating utensils, etc.), partially decayed radioactive markers, and other standard calibration and check sources. Disposal of this radioactive waste is usually accomplished by one of four different routes, depending on the facility's capacity for waste storage:

1. Return to vendor. Spent 99Mo-99mTc generators and sealed sources are often retuned to the vendor for disposal. Many regional radiopharmacies have also agreed to accept radioactive unit dose syringes and multidose vials from their customers on a daily basis. 2. Storage for decay. Radionuclides that will decay to background levels in a reasonably short period of time, usually less than 2 y, can be allowed to decay in storage for a minimum of 10 halflives where space permits. Prior to disposal as normal trash, the radioactive status of the waste must be determined to ascertain that it is indistinguishable from background with a n appropriate survey instrument, and all radioactive material labels must be removed or obliterated.

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6. RADIOPHARMACEUTICAL HANDLING PROCEDURES

3. Transfer to a licensed low-level radioactive waste disposal facility or broker. Items which cannot be returned to the vendor or items that have half-lives beyond those that can conveniently be stored for decay should be transferred to a licensed facility or broker. 4. Disposal via the sanitary sewer. Patient excreta disposal is routinely accomplished through the sanitary sewer system under an exemption provided in federal regulations. Provided releases are within acceptable release concentrations, other liquid-form radioactive materials disposal can be accomplished in this manner.

Radioactive wastes must be collected in containers that are clearly labeled and kept in areas where they are secure and adequately shielded. Housekeeping staff must be trained to identify such containers readily and instructed not to empty them inadvertently with the normal trash.

7. Radiation Safety Considerations for the Nursing Staff Routine nursing care usually involves close contact with most patients admitted to a health care facility. Areas of close nursing contact may include basic care (monitoringofvital signs, intravenous therapy, administration of medication); handling of bed pans, urinals and linens; collection of specimens (urine, blood, feces); and interviewing of patients (histories).

7.1 Radiopharmaceutical Administrations The radiopharmaceutical is administered to the patient either in the nuclear medicine department or on the health care unit. If the radiopharmaceutical is administered in the patient's room, the patient is transported to the nuclear medicine department after a predetermined interval and then returned after completion of the study. As an alternative, the imaging procedure may be done at the patient's bedside using mobile imaging equipment. In either of these situations, nursing care may be given immediately following radiopharmaceutical administrations, prior to the imaging procedure, and, when imaging is done in the patient's room, while the image is being acquired and after the mobile equipment leaves the bedside. The radiation exposure around the patient will be at or near maximum during this time. The handling of excreta or the collection of specimens may be necessary during this maximum exposure period and precautions are necessary to keep exposures to attending staff low.

7.2 Notification of Radiopharmaceutical Administration Any radiopharmaceutical administration should be noted in the patient chart. It also may be appropriate to include temporary written instructions and precautions that remain with the patient.

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7. RADIATION SAFETY CONSIDERATIONS

7.3 When Radioactive Precautions Are Necessary 7.3.1 The Patient 7.3.1.1 For Diagnostic Purposes. Table 7.1 provides data that have appeared in several published studies detailing the radiation levels around nuclear medicine patients at various times after the administration of different radiopharmaceuticals for diagnostic purposes (Castronovo et al., 1982b; Jankowski, 1984; Syed et al., 1982). The dose rate at 1m from the patient receiving a radiopharmaceutical rarely exceeds 0.01 mGy per h. One of the most frequently performed diagnostic tests, 99mTc MDP bone scintigram, accounts for a substantial fraction of nuclear medicine personnel exposures, especially during the gamma camera imaging procedure. This is because of the high frequency of bone studies, as well as the high dosage of radiopharmaceutical administered. Typical radiation doses to nuclear medicine technologists from selected 99"Tcprocedures are listed in Table 7.2 (Barrall and Smith, 1976).The radiation dose rates around bone-scan patients at various times after administration are presented in Table 5.1. Nurses encounter substantially fewer patients to whom radiopharmaceuticals have been administered than do nuclear medicine technologists and spend less time close to them. Therefore, it is anticipated that doses to nurses are lower than doses to nuclear medicine technologists. TABLE7.1-Radiation

Study

Bone

dose rates a t 1m from nuclear medicine patients (NCRP, 19896). Tie Dose

Agent Administered

*Tc MDP

MBq

740 740 740 740 Bone 740 *Tc MDP Blood pool =Tc RBC 740 CSFb "'In DTPA 18.5 20'Tl chloride Heart 740 Heart 185 *Tc HSA Heart 999 *Tc RBC Liver 148 *Tc S colloid Tumor "Ga citrate 111 "Measurement made at side of stretcher. bCerebrospinal fluid.

ARer Administration

0 l h 2h 3h 0 0 0 0 0 20 min 0 0

Rate (PGYh-')

9 6.3 4.7 3.5 25" 14 0.8 20" 15" 18 2 3.5

7.3 WHEN RADIOACTIVE PRECAUTIONS ARE NECESSARY

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37

TABLE 7.2-Dose received by nuclear medicine technologist from selected routine procedures.

Pmcedure

Agent

CBP

gg"TcDiphos gg"Tc04 Vc04

Infarct

99"TcPyro

Liver

TcSC 99mT~04

Bone Brain

Thyroid

Activity Administered (MBq)

555 740 740 555 148 74

Dose from a Single Routine Procedure (+Gy) Dosage fieparation and Assay Administration Imaging Total

0.2 0.4 0.4 0.1 0.1 0.2

0.1 0.2 0.2 0.1 0.2 0.1

5.4 2.2 0.3 0.2 0.3 0.4

5.7 2.8 0.9 0.4 0.6 0.7

Terebral blood flow.

7.3.1.2 For TherapeuticPurposes. When lS1Isodium iodide is used for cancer therapy (thyroid metastases), the radiation levels surrounding patients to whom the radiopharmaceutical has been administered can be substantial (Table 7.3) (Castronovo et al., 1982a). Because of this exposure potential, nurses handling such patients are usually issued personal monitors and the patient is restricted to a private room. Specific instructions shall be prescribed for nursing personnel. Abbreviated instructions shall be posted on the door of the patient's room where it can be seen by everyone. When prescribed radiation safety practice is followed, the radiation doses to nurses assigned to these patients is usually 0.1 mGy or less (see Table 7.4). These patients are usually hospitalized for 1to 3 d. Soluble 32P-labeledcompounds may also present a problem. Following administration, 20 percent of soluble 32Pmay be excreted in the urine over a 4 to 7 d period (Castronovo et al., 1982a). Care should be taken when handling urine, and gloves should be worn. When gloves are worn, care should be taken so that contamination is not spread from the gloves to other areas and so that hands are not contaminated while removing the gloves. 7.3.2

Collection and Handling of Excreta

7.3.2.1 From Diagnostic Dosages. The collection and subsequent handling of patient excreta (urine, feces) on the health care unit presents a possibility for radiation exposure and radiocontamination. With certain imaging procedures taking place at the patient's bedside, including injections for studies to be performed later in the nuclear medicine department, the nurse may collect urine at times that correspond to maximum activity for certain radiopharmaceuticals, such as 99mTc DTPA and &Tc MDP, which are eliminated from

7.3 WHEN RADIOACTIVE PRECAUTIONS ARE NECESSARY

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TABLE7.4-Doses associated with nursing care to I3lI therapy patients." Number of

Average Months

Dose Nurses Working <0.1 mGy 57 1.4 0.1 mGy 4 3.6 0.1 to 0.2 mGy 1 1.0 'Unpublished data (1984)from Frank P.Castronovo, Jr., Massachusetts General Hospital, Boston, Massachusetts.

the body via the kidneys (Castronovoet al., 1981;McAfeeet al., 1979). The time-activity relationships for 99"Tcdiphosphonate excretion in patients demonstrate that for a standard 740 MBq 99mTcMDP bone dosage, the 0 to 1h urine contains approximately 222 MBq of '%Tc activity, while the 1to 4 h and 4 to 7 h samples contain approximately 111MBq and 44.4 MBq, respectively (Castronovo, 1991; Castronovo et al., 1981).These data together with the distance related exposures are shown in Table 7.5. The total radiation dose to a handler would be a function of the time it takes to complete this task and the number of such tasks performed over a given time period. Universal precautions should prevent contamination and hands should be surveyed for contamination after the task is complete.

7.3.2.2 From Therapeutic Dosages. The patient activity and external dose rate from radiopharmaceuticals used in therapy decrease due to both radioactive decay and biological elimination. In addition, the same radiopharmaceutical may decrease a t quite different rates in different disease states (NCRP, 1995). Iodine-131 sodium iodide is administered orally for treatment of hyperthyroidism in dosages of 100 to 1,000 MBq and in dosages of 4,000 to 8,000 MBq for treatment of thyroid cancer. A comparison of hyperthyroid patient data and thyroid cancer patient data demonstrates a more rapid decrease of exposure rate in thyroid cancer patients. During the period of confinement due to their radioactive status, patients are normally kept in a private room and instructed to urinate directly into the commode or to collect and pour their urine into a special shielded container kept in their bathroom. This simple measure serves to reduce the exposure of nursing personnel who would otherwise be responsible for handling and disposal of urinals and urine. Patients being treated for hyperthyroidism do not present a problem for nursing personnel since they do not require hospitalization for radiation protection purposes. 7.3.3 Collected Specimens The collection of various specimens from patients to follow the course of their illness is routine. At times, these specimens will be

7.3 WHEN RADIOACTIVE PRECAUTIONS ARE NECESSARY

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radioactive, and handling precautions and restrictions should be specified. It is recommended that specimens be taken prior to the administration of a radiopharmaceutical especially if it is a therapeutic administration. If this cannot be done, then the necessary precautions must be enforced. For example, a sample of 99"Tccontaminated urine may be stored for decay prior to sending i t to the chemistry lab for analysis. This may be required when the sample is to be analyzed by radioimmunoassay. Additional specific procedures and precautions for nursing personnel attending diagnostic or therapeutic patients, or handling their body fluids, can be found in NCRP,1989b.

Glossary absorbed dose: the energy imparted to matter (e.g.,the body) by ionizing radiation per unit mass of irradiated material a t the point of interest. The unit of absorbed dose is the gray (Gy). accelerator:a device that accelerates charged particles (e.g., protons, electrons) to high speed in order to produce ionization or nuclear reactions in a target; often used for the production of certain radionuclides or directly for radiation therapy. The cyclotron and the linear accelerator (''LINAC") are types of accelerators. activity: a measure of the quantity of radioactive material, measured in transformations per unit time. The unit of activity is the becquerel (Bq). administration (of radioactive material): introduction of radioactive material directly into the body by injection, oral administration or by some other route. agreement state: any state with which the U.S. Nuclear Regulatory Commission or the Atomic Energy Commission has entered into a n effective agreement under Section 247b of the Atomic Energy Act of 1954. air k e m a rate constant (r,):a measure of the total energy released per unit time by a given amount of gamma-emitting radioactive material. The unit is m2 Gy Bq-' s-' (ICRU, 1980). annual reference levels of intake (ARLI): the activity of a radionuclide that, taken into the body during a year, would provide a committed effective dose to a person represented by Reference Man, equal to 20 mGy. The ARLI is expressed in becquerels (Bq). as low as reasonably achievable (ALARA): the principle of radiation protection that limits the radiation exposure of exposed persons to the lowest level reasonably achievable, economic and social factors having been considered. background: radiation originating in sources other than the one of primary concern. becquerel (Bq):the special name for the SI unit of activity which is equal to one transformation per second. by-product material: radioactive material produced by nuclear fission (fission products) or by neutron activation in a nuclear reactor or similar device. carcinogenesis: induction of cancer by radiation or any other agent (a somatic effect). central radiopharmacy: a facility that dispenses radiopharmaceuticals to a number of users or institutions. column:the solid matrix within a generator upon which the parent radionuclide is chemically or physically bound.

GLOSSARY

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43

committed effective dose, E (7):the committed equivalent doses to individual tissues or organs resulting from a n intake multiplied by the appropriate tissue weighting factor (wT)and then summed. E(T) = ZwTHT(7) where HT(7)is the committed equivalent dose in tissue T, w~is the weighting factor for tissue T, and T is the integration period in years. committed equivalent dose, HT(7):the equivalent dose in a particular organ or tissue accumulated in a specific period 7, after intake of a radionuclide. It is defined by:

where HT(T)is the equivalent dose rate in an organ or tissue T a t time t and T is given in years, i.e., T = 50 y is applicable to workers and T = 70 y is applicable to members of the public. contamination: radioactive material present in undesired locations; a source of background or possible hazard. derived reference air concentration (DRAC):the ARLI of a radionuclide divided by the volume of air inhaled by Reference Man in a working year (i.e., 2.4 X lo3 m3). The unit of DRAC is Bq m-3. dosage: the amount of radiopharmaceutical administered to a patient, measured in becquerels (Bq). dose: the amount of ionizing radiation absorbed by a person, organ or other absorber. dosage calibrator:a device (ionization chamber) for measuring the amount of radioactive material within a container. Used to verify dosage prior to administration. It is commercially available as a "dose calibrator." diethylene triamine pentaacetic acid (DTPA): a chelating substance usually labeled with a metal such as 9"Tc or 'llIn. DTPA is rapidly excreted from the body by the kidneys. effective dose (E): the sum over specified tissues of the products of the equivalent dose in a tissue (T) and the weighting factor for that tissue (wT),i.e., E = Z w T H T . effective dose equivalent (HE): the sum over the tissues of the product of effective dose equivalent (HT)in a tissue (T) and the weighting factor (wT)representing its proportion of the total stochastic (career and genetic) risk resulting from the irradiation of tissue (T) to the total risk when the whole body is irradiated uniformly, i.e., HE = ZTWT HT = Hwb. effective half-life (T,): the time required for the amount of a radionuclide deposited in a living organism to be diminished 50 percent as a result of the combined action ofradioactive decay (T,)and biological elimination (Tb),i.e., T,

=

TbTP

T,+T, ' eluate: the solvent c a b g the decay product when a generator is eluted. elute: to remove the daughter radionuclide from a generator using a suitable solvent. equivalent dose (HT):a quantity used for radiation-protection purposes that takes into account the different probability of effects which occur

44

1

GLOSSARY

with the same absorbed dose delivered by radiations with different W E values. I t is defined as the product of the averaged absorbed dose in a specified organ or tissue (DT) and the radiation weighting factor (w~). The unit of equivalent dose is joules per kilogram (Jkg-') and its special name is the sievert (Sv). excreta:waste material (perspiration, urine, stools) eliminated by the body. exposure: the incidence of ionizing radiation on living or inanimate material. Also, a measure of the ionization produced i n a specified mass of air by x or gamma radiation, which may be used as a measure of the ionizing radiation to which one is exposed. When using SI units, air kerma is often used in place of exposure. Air kerma has the units of J kg-I (Gy). In conventional units, the special unit of exposure is the roentgen (R). An exposure of 1 R corresponds to an air kerma of 8.7 mGy (see kerma, gray, roentgen). film badge: an assembly containing unexposed photographic film and one or more absorbers, worn by those working with radiation sources; when the film is developed one can estimate the dose and type of radiation to which the wearer was exposed. gamma camera: an imaging device that displays the distribution of radioactivity within a source such as the body. It records the quantity and distribution of photons emitted by the radioactive material in the area of interest. The gamma camera is the principal imaging device used i n nuclear medicine. generator:a device containing a radionuclide that decays to another radionuclide (decay product) that is to be extracted and used. The original radionuclide is firmly bound in the generator and remains behind (see eluate, elute). genetic effects: radiation effects induced in the offspring of irradiated persons (or animals), if conception occurs after exposure (see somatic effects). gray (Gy): an SI unit of radiation absorbed dose equal to 1joule of absorbed energy per kg of absorber. half-life:the time required for a radioactive substance to decay to one-half its original quantity. Physical half-life refers to radioactive decay, which where A is the activity follows the exponential model A = A, exp (-A&$), .. at time t, A, is the activity originally present, hph,is the physical decay constant, and Tphy= (In 2)(Aphy)-'.Biological half-life which relates to the rate of metabolic loss is more complex, but is often forced into a simple exponential model. Effective half-life combines the independent losses by physical decay and biological turnover: 1(Tefi)F1= 1(Tphy)Y1+ 1(Tbio)F1. hyperthyroidism: a condition in which an overactive thyroid gland produces excessive thyroid hormone, leading to a characteristic clinical picture. Since the thyroid uses iodine to make its hormone (thyroxine or T-4), radioactive iodine in small dosages can be used to image the thyroid and in large dosages to treat it (reduce its function). in vitro: from Latin "in glass"; refers to a procedure done outside the body (e.g.,in a test tube), as opposed to in uivo.

GLOSSARY

/

45

in vivo: from Latin "in life"; refers to a procedure carried out in the living body, as opposed to in vitro. ionization chamber: a device for detecting and measuring ionizing radiation as manifested by the ionization produced in gas within the chamber. This gas is normally air. ionizingradiation:electromagnetic radiation (x or gamma rays) or particulate radiation (alpha particles, beta particles, electrons, positrons, protons, neutrons, and heavy particles) capable of producing ions by direct or secondary processes in passage through matter. late somatic effects: radiation effects occurring a considerable time after exposure to radiation; these effects include mutagenesis, teratogenesis and carcinogenesis. latent period: the period between exposure to ionizing radiation and the appearance of radiation effects. monitor: to determine the level of ionizing radiation and radioactive contamination in a given region. Also a device used for this purpose. morbidity: illness of any type or the risk of such illness (e.g., number of illnesses per 1,000 appendectomies). mortality: death or the risk of death (e.g., number of deaths per 1,000 appendectomies). multidose:refers to a vial, etc., that contains enough of a radiopharmaceutical that doses for more than one patient can be taken from it. mutagenesis:induction of a change in genetic material by radiation or any other agent; this could be either a somatic or a genetic effect, depending on whether body cells or germ cells are affected. natural background radiation: radiation originating from natural sources such a s cosmic radiation, naturally radioactive minerals and gases in the earth and naturally radioactive elements in the body (14C, 40K), typically contributes a dose of 1 to 3 mGy per y in the United States. nuclide: a n atom as specified by its atomic number and atomic weight. occupational dose: the dose received by an individual in a restricted area, or in the course of employment in which the individual's duties necessarily involve exposure to radiation (medical doses involving diagnosis or treatment of the exposed individual are excluded). occupationally exposed: exposed to radiation in connection with occupational duties, e.g., nuclear medicine technologists, nurses, physicians, etc. positron emissiontomography (PET):an imaging technique using radioisotopes that emit positrons (positively charged electrons), whose annihilation photons are imaged i n coincidence to form tomographic views of the bodv. radiation protection survey: evaluation of the radiation hazards incidental to the production, use or presence of radioactive materials or other source of radiation. Such evaluation includes measurement of the dose rates of radiation being emitted from the material. radiation weighting factor (wR):a factor used for radiation protection purposes that accounts for differences in biological effectiveness between different radiations. The radiation weighting factor (wR)is independent of the tissue weighting factor (wT).

-

46

/

GLOSSARY

radioactive waste: waste that is sufficiently radioactive to be detected above background levels, thereby requiring special handling, storage, transportation and disposal. radioimmunoassay (RIA): an in vitro test in which very small quantities of certain substances in blood, urine, etc. can be measured by using specific antibodies or other agents which have been labeled with radioactive tracers. Since the patient does not receive the radioactive material, there is no patient radiation exposure involved. radioisotope: an unstable atom having the same atomic number but a different number of neutrons in the nucleus than the comparable stable element. radionuclide: a radioactive nuclide (see nuclide). radionuclide therapy: radiation therapy from a radiopharmaceutical given directly to the patient (e.g., l8'I for hyperthyroidism). radiopharmaceutical: a radioactive substance administered directly to a patient for diagnostic or therapeutic nuclear medicine procedures. A radiopharmaceutical contains two parts, the radionuclide and the pharmaceutical, eg., 99mTc DTPA. In some cases the two are one, e.g., 133Xegas. Reference Man: a model with the anatomical and physiological characteristics of an adult male as d e h e d in ICRP Publication 23 (ICRP, 1975). scan: an image of the distribution of radioactivity in the body, strictly speaking made with a rectilinear scanner, but now loosely applied to any such image. Also, to make such an image. sealed source: radioactive material permanently bonded or fixed within a capsule or matrix designed to prevent release and dispersal of the radioactive material under the most severe conditions likely to be encountered in normal use and handling. single photon emission computed tomography (SPECTI: an imaging technique in which one or more gamma cameras sample a region of the body from several angles, producing tomographic images ("slices") of it. sievert (Sv): the special name for the unit of effective dose and equivalent dose, 1 Sv = 1J kg-' somatic effects: radiation effects induced in the person irradiated (see genetic effects). stochastic effects: effects, the probability of which, rather than their severity, is a function of radiation dose without threshold. survey: (see radiation protection survey). survey meter: a device for monitoring the dose rate in an area. syringe shield: a cylinder made of lead-containingglass that absorbs radiation emitted from radioactive material in a syringe, thereby reducing the radiation dose to personnel. Systeme Internationale (SI): a system of scientific units designed to foster uniformity in measurements. In nuclear medicine the new SI units of becquerel, gray and sievert have replaced the conventional units of curie, rad and rem. teratogenesis: the production of physical defects in offspring in utero. thermoluminescent dosimeter (TLD): a dosimeter containing a crystalline solid for measuring radiation dose, plus filters (absorbers) to help

GLOSSARY

1

47

characterize the types of radiation encountered. (When heated, TLD crystals that have been exposed to ionizing radiation give off light proportional to the energy they received from the radiation). tissue weighting factor (wT): a factor that indicates the ratio of the risk of stochastic effects attributable to irradiation of a given organ or tissue to the total riskwhen the whole body is uniformly irradiated. w~is independent of the radiation type or energy. tracer: a radiopharmaceutical used to trace a physiological or biochemical process without affecting it. (Strictly speaking, a tracer does not have to be radioactive, but in common usage it is.) unit dosage: a precalibrated single dosage of a radiopharmaceutical in an individual container, intended for use in only one patient.

References AHLUWALIA, B., ALLEN, E.W., BASMADJIAN, G. and ICE, R. (1981). "The role of nuclear pharmacy in reducing radiation exposure," Health P h y ~40, . 728-729. AMA (1991). American Medical Association. Current Procedural Terminology, 5th ed. (American Medical Association, Chicago). ANS (1986). American Nuclear Society. "Radioactive materials transportA policy statement of the American Nuclear Society," ANS NEWS, September (American Nuclear Society, Chicago). ASSIMAKOPOULOS, P.A., IOANNIDES, K.G., PAKOU, A.A., LOLIS, D., ZIKOPOULOS, K. and DUSIAS, B. (1989). "Radiocesium levels measured in breast milk one year after the reactor accident at Chernobyl," Health Phys. 56,103-106. BARRALL, R.C. and SMITH, S.I. (1976)."Personnel radiation exposure and protection from -Tc radiations," pages 77 to 97 in Biophysical Aspects of the Medical Use of Technetium-99m,Kereiakes, J.G. and Corey, K.R., Eds., AAPM Monograph No. 1 (American Institute of Physics, Inc., New York). BATCHELOR, S., PENFOLD, A., ARIC, I. andHUGGINS, R. (1991). "Radiation dose to the hands in nuclear medicine," Nucl. Med. Commun. 12, 439444. BENEDETTO, A.R., DZIUK, T.W. and NUSYNOWITZ, M.L. (1989). "Population exposure from nuclear medicine procedures: Measurement data," Health Phys. 57, 725-731. BRADLEY, F.J., JONES, A. and KJ3LLY, R. (1977). "Transport worker radiation exposures handling air shipments of radioactive materials," pages 347 to 350 in Proceedings N t h International Congress,International Radiation Protection Association, Volume 2 (International Radiation Protection Association, Fontenay Aux Roses, France). CAREY, J.E., JR. and SWANSON, D.P. (1979). ''Thyroid contamination from airborne 1-131," J. Nucl. Med. 20, 362. CARTER, M.W., GASPER, J.T. and KAHN, B. (1982). "Transportation of radioactive material in Georgia," Health Phys. 42, 759-775. CASTRONOVO, F.P., JR. (1991). "Time dependent radiation exposures surrounding technetium-99m MDP patients," J. Nucl. Med. Technol. 19, 182-184. CASTRONOVO, F.P., JR., MCKUSICK, K.A. and STRAUSS, H.W. (1981). "Bladder wall dosimetry after the administration of 99mTc-diphosphonate," Health Phys. 40, 744-746. CASTRONOVO, F.P., JR., BEH, R.A., andVIELLEUX, N.M. (1982a). "Dosimetric considerations while attending hospitalized 1-131 therapy patients," J. Nucl. Med. Technol. 10, 157.

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CASTRONOVO, F.P., JR., WEBSTER, E.W., STRAUSS, K.W., BREEN, C., HOLLEY, M. and FOLDING, F. (1982b). A Health Physics Guide for Patient Care Units: The Radiation Precautions Associated with Patients Undergoing Diagnostic Radiopharmaceutical Procedures (Massachusetts General Hospital, Boston). CRAWFORD, E.S., QUATN, B.C. and ZAKEN, A.M. (1992). "Air and surface contamination resulting from lung ventilation aerosol procedures," J. Nucl. Med. Technol. 20, 151-154. DODD, B. and HUMPHRIES, L.L. (1988). "Hazards assessment of worst case transportation accidents involving typical radioactive material shipments," Health Phys. 55,963-983. DYDEK, G.J. and BLUE, P.W. (1988). "Human breast milk excretion of iodine-131 following diagnostic and therapeutic administration to a lactating patient with Graves' disease," J. Nucl. Med. 29, 407-410. EARLY, P.J. (1987). "Radiation safety and handling of therapeutic radionuclides," Nucl. Med. Biol. 14, 263-267. FAILLA, L. (1977). "A statistical analysis of low-radiation packages in the transport of radioactive material," Health Phys. 33, 183-189. FAW, R.E. (1992). "Absorbed doses to skin from radionuclide sources on the body surface," Health Phys. 63, 443-448. GA'I'TAVECCHIA, E., GHINI, S., TONELLI, D., GORI, G., C A M . G. and GUERRESI, E. (1989). "Cesium-137 levels in breast milk and placentae after fallout from the reactor accident a t Chernobyl," Health Phys. 56, 245-248. GOSS, S.G. (1975). "Sizes of population needed to detect a n increase in disease risk when the levels of risk in the exposed and the controls are specified: Examples from cancer induced by ionizing radiation," Health Phys. 29,715-721. HEDRICK, W.R., DI SIMONE, R.N. and KEEN, R.L. (1986). "Radiation dosimetry from breast milk excretion of radioiodine and pertechnetate," J. Nucl. Med. 27, 1569-1571. HEDRICK, W.R., DI SIMONE, R.N. and KEEN, R.L. (1989). "Excretion of radioiodine in breast milk," J. Nucl. Med. 30, 127-128. HENDEE, W.R. and EDWARDS, F.M. (1990). "Trends in radiation protection of medical workers," Health Phys. 58, 251-257. HUMPHRIES, L.L. and DODD, B. (1989). "Risks of radioactive material transportation accidents in Oregon," Health Phys. 57, 131-139. ICRP (1975). International Commission on Radiological Protection. Reference Man:Anatomical, Physiological and Metabolic Characteristics, ICRP Publication 23 (Pergamon Press, Elmsford, New York). ICRP (1991a). International Commission on Radiological Protection. 1990 Recommendations of the International Commission on Radiological Protection, ICRP Publication 60, Annals of the ICRP 21 (Pergamon Press, Elmsford, New York). ICRP (1991b). International Commission on Radiological Protection. Risks Associated with Ionising Radiations, Annals of the ICRP 22 (Pergamon Press, Elmsford, New York).

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The NCRP The National Council on Radiation Protection and Measurements is a nonprofit corporation chartered by Congress in 1964 to: 1. Collect, analyze, develop and disseminate in the public interest information and recommendations about (a) protection against radiation and (b) radiation measurements, quantities and units, particularly those concerned with radiation protection. 2. Provide a means by which organizations concerned with the scientific and related aspects ofradiation protection and of radiation quantities, units and measurements may cooperate for effective utilization of their combined resources, and to stimulate the work of such organizations. 3. Develop basic concepts about radiation quantities, units and measurements, about the application of these concepts, and about radiation protection. 4. Cooperate with the International Commission on Radiological Protection, the International Commission on Radiation Units and Measurements, and other national and international organizations, governmental and private, concerned with radiation quantities, units and measurements and with radiation protection. The Council is the successor to the unincorporated association of scientists known as the National Committee on Radiation Protection and Measurements and was formed to carry on the work begun by the Committee in 1929. The Council is made up of the members and the participants who serve on the scientific committees of the Council. The Council members who are selected solely on the basis oftheir scientific expertise are drawn from public and private universities, medical centers, national and private laboratories and industry. The scientific committees, composed of experts having detailed knowledge and competence in the particular area of the committee's interest, draft proposed recommendations. These are then submitted to the full membership of the Council for careful review and approval before being published. The following comprise the current officers and membership of the Council:

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President Vice President Secretary and Treasurer Assistant Secretary Assistant Treasurer Members S m o m ABRAHAMSON S S. J ~ EADELSTEIN PETERR. ALMOND LARRYL. ANDERSON LYNNR. ANSPAUGH JOHN W. BAUM HAROLD L. BECK MICHAELA. BENDER B. GORDON BLAYLOCK BRUCEB. BOECKER JOHN D. BOICE.JR. &DR& BOWIUE LESLIEA. BRABY JOHN W. BRAND ROBERT L. BRENT A. BERTRAND BRILL ANTONEL. BROOKS PAULL. CARSON JAMES E. CLEAVER J. DONALD COSSAIRT FREDT. CROSS Gnu. DE PLANQUE SARAHDONALDSON WILLIAMP. DORNSIFE CARLH. DURNEY

KEITHF. ECKERMAN THOMAS F. GESELL ETHELS. GILBERT JOEL E. GRAY h ~ m w. GW ERICJ. IIW NAOMIH. m y W m R. HENDEE DAVIDG. HOEL F. OWENHOFFNIAN DONALD G. JACOBS A. EVERET~E JAMES, JR JOHN R. JOHNSON BWNDKAHN KENNETH R. KASE Arm KRONENBERG HAROLD L. KUNDEL CHARLES E. LAND JOHN B. LITIZE RICHARD A. LUBEN ROGER0.MCCLELLAN BARBARA J. MCNEIL CHARLESB. MEINHOLD FREDA. METPLER CHARLESW. MILLER Honorary Members

LAURISTON S.TAYLOR,Honorary President WARREN K SINCLAIR, President Emeritus THOMAS S. ELY RICHARD F. FOSTER HVMER L. F'RIEDELL R.J. MICHAEL FRY ROBERT0.G ~ R S O N JOHNW. YPAULC.HODGES W1LFm B. MANN A ALAN MOGHISSI Kmu Z. MORGAN ROBERTJ. NELSEN WESLEYL. NYBORG CHESTER R. RICHMOND

THE NCRP

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Currently, the following subgroups are actively engaged in formulating recommendations: Basic Radiation Protection Criteria SC 1-4 Extrapolation of Risk from Non-Human Experimental Systems to Man SC 1-5 Uncertainty in Risk Estimates SC 1-6 Basis for the Linearity Assumption SC 1-7 Information Needed to Make Radiation Protection Recommendations for Travel Beyond Low-Earth Orbit Structural Shielding Design and Evaluation for Medical Use of X Rays and Gamma Rays of Energies Up to 10 MeV Operational Radiation Safety SC 46-8 Radiation Protection Design Guidelines for Particle Accelerator Facilities SC 46-10 Assessment of Occupational Doses from Internal Emitters SC 46-11 Radiation Protection During Special Medical Procedures SC 46-13 Design of Facilities for Medical Radiation Therapy Dosimetry and Metabolism of Radionuclides SC 57-2 Respiratory Tract Model SC 57-9 Lung Cancer Risk SC 57-10 Liver Cancer Risk SC 57-14 Placental Transfer SC 57-15 Uranium SC 57-16 Uncertainties in the Application of Metabolic Models Radiation Exposure Control in a Nuclear Emergency Radionuclides i n the Environment SC 64-17 Uncertainty in Environmental Transport in the Absence of Site Specific Data SC 64-18 Risks from Space Applications of Plutonium SC 64-19 Historical Dose Evaluation SC 64-20 Contaminated Soil SC 64-21 Decontamination and Decommissioning of Facilities Biological Effects and Exposure Criteria for Ultrasound Radiation Protection in Mammography Guidance on Radiation Received in Space Activities Risk of Lung Cancer from Radon Hot Particles in the Eye, Ear or Lung Radioactive and Mixed Waste SC 87-1 Waste Avoidance and Volume Reduction SC 87-2 Waste Classification Based on Risk SC 87-3 Performance Assessment SC 87-4 Management of Waste Metals Containing Radioactivity Fluence as the Basis for a Radiation Protection System for Astronauts Nonionizing Electromagnetic Fields SC 89-1 Biological Effects of Magnetic Fields SC 89-3 Extremely Low-Frequency Electric and Magnetic Fields SC 89-4 Modulated Radiofrequency Fields SC 89-5 Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields

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SC 92 SC 93

THENCRP Radiation Protection in Medicine SC 91-1 Precautions in the Management of Patients Who Have Received Therapeutic Amounts of Radionuclides SC 91-2 Dentistry Policy Analysis and Decision Making Radiation Measurement

In recognition of its responsibility to facilitate and stimulate cooperation among organizations concerned with the scientific and related aspects of radiation protection and measurement, the Council has created a category of NCRP Collaborating Organizations. Organizations or groups of organizations that are national or international in scope and are concerned with scientific problems involving radiation quantities, units, measurements and effects, or radiation protection may be admitted to collaborating status by the Council. Collaborating Organizations provide a means by which the NCRP can gain input into its activities from a wider segment of society. At the same time, the relationships with the Collaborating Organizations facilitate wider dissemination of information about the Council's activities, interests and concerns. Collaborating Organizations have the opportunity to comment on draft reports (at the time that these are submitted to the members of the Council). This is intended to capitalize on the fact that Collaborating Organizations are in an excellent position to both contribute to the identification of what needs to be treated in NCRP reports and to identify problems that might result from proposed recommendations. The present Collaborating Organizations with which the NCRP maintains liaison are as follows: American Academy of Dermatology American Academy of Environmental Engineers American Academy of Health Physics American Association of Physicists in Medicine American College of Medical Physics American College of Nuclear Physicians American College of Occupational and Environmental Medicine American College of Radiology American Dental Association American Industrial Hygiene Association American Institute of Ultrasound in Medicine American Insurance Services Group American Medical Association American Nuclear Society American Pharmaceutical Association American Pediatric Medical Association American Public Health Association American Radium Society American Roentgen Ray Society

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American Society of Health-System Pharmacists American Society of Radiologic Technologists American Society for Therapeutic Radiology and Oncology Association of University Radiologists Bioelectromagnetics Society Campus Radiation Safety Officers College of American Pathologists Conference of Radiation Control Program Directors Council on Radionuclides and Radiopharmaceuticals Defense Nuclear Agency Electric Power Research Institute Electromagnetic Energy Association Federal Communications Commission Federal Emergency Management Agency Genetics Society of America Health Physics Society Institute of Nuclear Power Operations International Brotherhood of Electrical Workers National Aeronautics and Space Administration National Association of Environmental Professionals National Electrical Manufacturers Association National Institute of Standards and Technology Nuclear Energy Institute Office of Science and Technology Policy Oil, Chemical and Atomic Workers Union Radiation Research Society Radiological Society of North America Society of Nuclear Medicine United States Air Force United States Army United States Coast Guard United States Department of Energy United States Department of Housing and Urban Development United States Department of Labor United States Department of Transportation United States Environmental Protection Agency United States Navy United States Nuclear Regulatory Commission United States Public Health Services Utility Workers Union of America

The NCRP has found its relationships with these organizations

to be extremely valuable to continued progress in its program. Another aspect of the cooperative efforts of the NCRP relates to the Special Liaison relationships established with various governmental organizations that have an interest in radiation protection and measurements. This liaison relationship provides: (1)an opportunity for participating organizations to designate an individual to provide liaison between the organization and the NCRP; (2) that the individual designated will receive copies of draft NCRP reports (at the time that these are submitted to the members of the Council) with an

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invitation to comment, but not vote; and (3) that new NCRP efforts might be discussed with liaison individuals as appropriate, SO that they might have an opportunity to make suggestions on new studies and related matters. The following organizations participate in the Special Liaison Program: Australian Radiation Laboratory Commissariat a 1'Energie Atomique (France) Commission of the European Communities Health Council of the Netherlands International Commission on Non-Ionizing Radiation Protection Japan Radiation Council Korea Institute of Nuclear Safety National Radiological Protection Board (United Kingdom) National Research Council (Canada) South African Forum for Radiation Protection Ultrasonics Institute (Australia)

The NCRP values highly the participation of these organizations in the Special Liaison Program. The Council also benefits significantly from the relationships established pursuant to the Corporate Sponsor's Program. The program facilitates the interchange of information and ideas and corporate sponsors provide valuable fiscal support for the Council's program. This developing program currently includes the following Corporate Sponsors: Amersham Corporation Commonwealth Edison Consolidated Edison Duke Power Company Eastman Kodak Company Florida Power Corporation Landauer, Inc. 3M New York Power Authority Public Service Electric and Gas Company Westinghouse Electric Corporation

The Council's activities are made possible by the voluntary contribution of time and effort by its members and participants and the generous support of the following organizations: Agfa Corporation Alfred P. Sloan Foundation Alliance of American Insurers American Academy of Dermatology American Academy of Oral and Maxillofacial Radiology

THENCRP American Association of Physicists in Medicine American Cancer Society American College of Medical Physics American College of Nuclear Physicians American College of Occupational and Environmental Medicine American College of Radiology American College of Radiology Foundation American Dental Association American Healthcare Radiology Administrators American Industrial Hygiene Association American Insurance Services Group American Medical Association American Nuclear Society American Osteopathic college of Radiology American Pediatric Medical Association American Public Health Association American Radium Society American Roentgen Ray Society American Society of Radiologic Technologists American Society for Therapeutic Radiology and Oncology American Veterinary Medical Association American Veterinary Radiology Society Association of University Radiologists Battelle Memorial Institute Canberra Industries, Inc. Chem Nuclear Systems Center for Devices and Radiological Health College of American Pathologists Committee on Interagency Radiation Research and Policy Coordination Commonwealth of Pennsylvania Consumers Power Company Council on Radionuclides and Radiopharmaceuticals Defense Nuclear Agency Duke Power Company Edison Electric Institute Edward Mallinckrodt, Jr. Foundation EG&G Idaho, Inc. Electric Power Research Institute Federal Emergency Management Agency Florida Institute of Phosphate Research Fuji Medical Systems, U.S.A., Inc. Genetics Society of America Health Effects Research Foundation (Japan) Health Physics Society Institute of Nuclear Power Operations James Picker Foundation Martin Marietta Corporation Motorola Foundation National Aeronautica and Space Administration National Association of Photographic Manufacturers National Cancer Institute National Electrical Manufacturers Association

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National Institute of Standards and Technology Nuclear Energy Institute Picker International Radiation Research Society Radiological Society of North America Richard Lounsbery Foundation Sandia National Laboratory Siemens Medical Systems, Inc. Society of Nuclear Medicine Society of Pediatric Radiology United States Department of Energy United States Department of Labor United States Environmental Protection Agency United States Navy United States Nuclear Regulatory Commission Victoreen, Inc.

Initial funds for publication of NCRP reports were provided by a grant from the James Picker Foundation. The NCRP seeks to promulgate information and recommendations based on leading scientific judgment on matters of radiation protection and measurement and to foster cooperation among organizations concerned with these matters. These efforts are intended to serve the public interest and the Council welcomes comments and suggestions on its reports or activities from those interested in its work.

NCRP Publications NCRP publications are distributed by the NCRP Publications Office. Information on prices and how to order may be obtained by directing an inquiry to: NCRP Publications 79 10 Woodmont Avenue Suite 800 Bethesda, MD 20814-3095 The currently available publications are listed below.

NCRP Reports No. 8

Title

Control and Removal ofRadioactive Contamination i n Laboratories (1951) Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides i n Air and i n Water for Occupational Exposure (1959) [Includes Addendum 1issued in August 19631 Measurement of Neutron Flux and Spectra for Physical and Biological Applications (1960) Measurement ofAbsorbed Dose of Neutrons, and of Mixtures of Neutrons and Gamma Rays (1961) Stopping Powers for Use with Cavity Chambers (1961) Safe Handling of Radioactive Materials (1964) Radiation Protection in Educational Institutions (1966) Dental X-Ray Protection (1970) Radiation Protection in Veterinary Medicine ( 1970) Precautions i n the Management of Patients Who Have Received Therapeutic Amounts of Radionuclides (1970) Protection Against Neutron Radiation (1971) Protection Against Radiation from Brachytherapy Sources (1972) Specification of Gamma-Ray Brachytherapy Sources (1974) Radiological Factors Affecting Decision-Making i n a Nuclear Attack (1974)

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NCRP PUBLICATIONS

Krypton-85 i n the Atmosphere-Accumulation, Biological Significance, and Control Technology (1975) Alpha-Emitting Particles in Lungs (1975) Tritium Measurement Techniques (1976) Structural Shielding Design and Evaluation for Medical Use of X Rays and Gamma Rays of Energies Up to 10 MeV (1976) Environmental Radiation Measurements (1976) Radiation Protection Design Guidelines for 0.1-100 MeV Particle Accelerator Facilities (1977) Cesium-137from the Environment to Man: Metabolism and Dose (1977) Medical Radiation Exposure of Pregnant and Potentially Pregnant Women (1977) Protection of the Thyroid Gland i n the Event of Releases of Radioiodine (1977) Instrumentation and Monitoring Methods for Radiation Protection (1978) A Handbook of Radioactivity Measurements Procedures, 2nd ed. (1985) Operational Radiation Safety Program (1978) Physical, Chemical, and Biological Properties of Radwcerium Relevant to Radiation Protection Guidelines (1978) Radiation Safety Training Criteria for Industrial Radiography (1978) Tritium i n the Environment (1979) Tritium and Other Radionuclide Labeled Organic Compounds Incorporated in Genetic Material (1979) Influence o f Dose and Its Distribution i n Time on DoseResponse Relationships for Low-LET Radiations (1980) Management of Persons Accidentally Contaminated with Radionuclides (1980) Radiofrequency Electromagnetic Fields-Properties, Quantities and Units, Biophysical Interaction, and Measurements (1981) Radiation Protection i n Pediatric Radiology (1981) Dosimetry of X-Ray and Gamma-Ray Beams for Radiation Therapy in the Energy Range 10 keV to 50 MeV (1981) Nuclear Medicine-Factors Influencing the Choice and Use of Radionuclides i n Diagnosis and Therapy (1982) Operational Radiation Safety-Training (1983) Radiation Protection and Measurement for Low-Voltage Neutron Generators (1983)

NCRP PUBLICATIONS

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65

Protection in Nuclear Medicine and Ultrasound Diagnostic Procedures in Children (1983) Biological Effects of Ultrasound: Mechanisms and Clinical Implications (1983) Iodine-129: Evaluation of Releases from Nuclear Power Generation (1983) Radiological Assessment: Predicting the Transport, Bioaccumulation, and Uptake by Man of Radionuclides Released to the Environment (1984) Exposures from the Uranium Series with Emphasis on Radon and Its Daughters (1984) Evaluation of Occupational and Environmental Exposures to Radon and Radon Daughters in the United States (1984) Neutron Contamination from Medical Electron Accelerators (1984) Induction of Thyroid Cancer by Ionizing Radiation (1985) Carbon-14 in the Environment (1985) SI Units in Radiation Protection and Measurements (1985) The Experimental Basis for Absorbed-Dose Calculations in Medical Uses of Radionuclides (1985) General Concepts for the Dosimetry of Internally Deposited Radionuclides (1985) Mammography-A User's Guide (1986) Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields (1986) Use ofBioassay Proceduresfor Assessment oflnternal Radionuclide Deposition (1987) Radiation Alarms and Access Control Systems (1986) Genetic Effects from Internally Deposited Radionuclides (1987) Neptunium: Radiation Protection Guidelines (1988) Public Radiation Exposure from Nuclear Power Generation in the United States (1987) Ionizing Radiation Exposure of the Population of the United States (1987) Exposure of the Population in the United States and Canada from Natural Background Radiation (1987) Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources (1987) Comparative Carcinogenicity of Ionizing Radiation and Chemicals (1989) Measurement of Radon and Radon Daughters in Air (1988) Guidance on Radiation Received in Space Activities (1989) Quality Assurance for Diagnostic Imaging (1988) Exposure of the U.S. Population from Diagnostic Medical Radiation (1989)

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NCRP PUBLICATIONS

Exposure of the U.S. Population from Occupational Radiation (1989) Medical X-Ray, Electron Beam and Gamma-Ray Protection for Energies Up to 50 MeV (Equipment Design, Performance and Use) (1989) Control of Radon in Houses (1989) The Relative Biological Effectiveness ofRadiations of Different Quality (1990) Radiation Protection for Medical and Allied Health Personnel (1989) Limit for Exposure to "Hot Particles" on the Skin (1989) Implementation of the Principle of As Low As Reasonably Achievable (ALARA) for Medical and Dental Personnel (1990) Conceptual Basis for Calculations of Absorbed-Dose Distributions (1991) Effects of Ionizing Radiation on Aquatic Organisms (1991) Some Aspects of Strontium Radiobiology (1991) Developing Radiation Emergency Plans for Academic, Medical or Industrial Facilities (1991) Calibration of Survey Instruments Used i n Radiation Protection for the Assessment of Ionizing Radiation Fields and Radioactive Surface Contamination (1991) Exposure Criteria for Medical Diagnostic Ultrasound:I. Criteria Based on Thermal Mechanisms (1992) Maintaining Radiation Protection Records (1992) Risk Estimates for Radiation Protection (1993) Limitation of Exposure to Ionizing Radiation (1993) Research Needs for Radiation Protection (1993) Radiation Protection i n the Mineral Extraction Industry (1993) A Practical Guide to the Determination of Human Exposure to Radiofrequency Fields (1993) Dose Control at Nuclear Power Plants (1994) Principles and Application of Collective Dose in Radiation Protection (1995) Use of Personal Monitors to Estimate Effective Dose Equivalent and Effective Dose to Workers for External Exposure to Low-LET Radiation (1995) Screening Models for Releases of Radionuclides to Atmosphere, Surface Water, and Ground (1996) Sources and Magnitude of Occupational and Public Exposures from Nuclear Medicine Procedures (1996)

NCRP PUBLICATIONS

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67

Binders for NCRP reports are available. Two sizes make it possible to collect into small binders the "old series" of reports (NCRP Reports Nos. 8-30)and into large binders the more recent publications (NCRP Reports Nos. 32-124). Each binder will accommodate from five to seven reports. The binders carry the identification "NCRP Reports" and come with label holders which permit the user to attach labels showing the reports contained in each binder. The following bound sets of NCRP reports are also available: Volume I. NCRP Reports Nos. 8 , 2 2 Volume 11. NCRP Reports Nos. 23, 25, 27, 30 Volume 111. NCRP Reports Nos. 32, 35, 36, 37 Volume IV. NCRP Reports Nos. 38, 40, 41 Volume V. NCRP Reports Nos. 42,44,46 Volume VI. NCRP Reports Nos. 47, 49,50,51 Volume VII. NCRP Reports Nos. 52, 53, 54, 55, 57 Volume VIII. NCRP Report No. 58 Volume IX.NCRP Reports Nos. 59,60,61, 62,63 Volume X. NCRP Reports Nos. 64,65, 66,67 Volume XI. NCRP Reports Nos. 68,69, 70, 71, 72 Volume XII. NCRP Reports Nos. 73, 74, 75, 76 Volume XIII. NCRP Reports Nos. 77, 78, 79, 80 Volume XIV. NCRP Reports Nos. 81,82,83, 84,85 Volume XV.NCRP Reports Nos. 86, 87,88,89 Volume XVI. NCRP Reports Nos. 90,91,92,93 Volume XVII. NCRP Reports Nos. 94,95, 96,97 Volume XVIII. NCRP Reports Nos. 98,99, 100 Volume XIX NCRP Reports Nos. 101,102,103, 104 Volume XX.NCRP Reports Nos. 105,106, 107, 108 Volume XXI. NCRP Reports Nos. 109, 110, 111 Volume XXII. NCRP Reports Nos. 112, 113, 114 Volume XXIII. NCRP Reports Nos. 115, 116, 117, 118 (Titles of the individual reports contained in each volume are given above.)

NCRP Commentaries No.

Title

1

Krypton-85 in the Atmosphere-With Specific Reference to the Public Health Significance of the Proposed Controlled Release at Three Mile Island (1980) Screening Techniques for Determining Compliance with

3

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NCRP PUBLICATIONS

Environmental Standards-Releases of Radionuclides to the Atmosphere (1986), Revised (1989) Guidelines for the Release o f Waste Water from Nuclear Facilities with Special Reference to the Public Health Significance of the Proposed Release of Treated Waste Waters at Three Mile Island (1987) Review of the Publication, Living Without Landfills (1989) Radon Exposure of the U.S. Population-Status of the Problem (1991) Misadministration of Radioactive Material in MedicineScientific Background (1991) Uncertainty i n NCRP Screening Mo&ls Relating to Atmospheric Transport, Deposition and Uptake by Humans (1993) Considerations Regarding the Unintended Radiation Exposure of the Embryo, Fetus or Nursing Child (1994) Advising the Public about Radiation Emergencies: A Document for Public Comment (1994) Dose Limits for Individuals Who Receive Exposure from Radionuclide Therapy Patients (1995) Radiation Exposure and High-Altitude Flight (1995) A n Introduction to Eficacy in Diagnostic Radiology and Nuclear Medicine (Justification of Medical Radiation Exposure) (1995) Proceedings of the Annual Meeting No.

Title

1

Perceptions of Risk, Proceedings of the Fifteenth Annual Meeting held on March 14-15,1979(includingTaylor Lecture No. 3) (1980) Critical Issues in Setting Radiation Dose Limits, Proceedings of the Seventeenth Annual Meeting held on April 8-9, 1981 (including Taylor Lecture No. 5) (1982) R a d i a t i o n Protection a n d New Medical Diagnostic Approaches, Proceedings of the Eighteenth Annual Meeting held on April 6-7, 1982 (including Taylor Lecture No. 6) (1983) Environmental Radioactivity, Proceedings of the Nineteenth Annual Meeting held on April 6-7,1983 (including Taylor Lecture No. 7) (1983) Some Issues Important in Developing Basic Radiation Protection Recommendations, Proceedings of the Twentieth

NCRP PUBLICATIONS

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69

Annual Meeting held on April 4-5,1984 (including Taylor Lecture No. 8) (1985) Radioactive Waste, Proceedings of the Twenty-first Annual Meeting held on April 3-4,1985 (includingTaylor Lecture No. 9) (1986) Nonionizing Electromagnetic Radiations and Ultrasound, Proceedings of the Twenty-second Annual Meeting held on April 2-3,1986 (includingTaylor Lecture No. 10)(1988) New Dosimetry at Hiroshima and Nagasaki and Its Implications for Risk Estimates, Proceedings of the Twenty-third Annual Meeting held on April 8-9, 1987 (includingTaylor Lecture No. 11) (1988) Radon, Proceedings of the Twenty-fourth Annual Meeting held on March 30-31, 1988 (including Taylor Lecture No. 12) (1989) Radiation Protection Today-The NCRP at Sixty Years, Proceedings of the Twenty-fifth Annual Meeting held on April 5-6, 1989 (including Taylor Lecture No. 13) (1990) Health and Ecological Implications of Radioactively Contaminated Environments, Proceedings of the Twenty-sixth Annual Meeting held on April 4-5, 1990 (including Taylor Lecture No. 14) (1991) Genes, Cancer and Radiation Protection, Proceedings of the Twenty-seventh Annual Meeting held on April 3-4, 1991 (including Taylor Lecture No. 15) (1992) Radiation Protection in Medicine, Proceedings of the Twentyeighth Annual Meeting held on April 1-2, 1992 (including Taylor Lecture No. 16) (1993) Radiation Science and Societal Decision Making, Proceedings of the Twenty-ninth Annual Meeting held on April 7-8, 1993 (including Taylor Lecture No. 17) (1994)

Lauriston S. Taylor Lectures No.

Title

1

The Squares of the Natural Numbers in Radiation Protection by Herbert M. Parker (1977) Why be Quantitative about Radiation Risk Estimates? by Sir Edward Pochin (1978) Radiation Protection-Concepts and Trade Offs by Hymer L. Friedell (1979) [Available also in Perceptions of Risk, see above] From "Quantity of Radiation"and "Dose" to "Exposure" and

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NCRP PUBLICATIONS

"Absorbed Dose9'-An Historical Review by Harold 0. Wyckoff (1980) How Well Can We Assess Genetic Risk? Not Very by James F. Crow (1981) [Available also in Critical Issues in Setting Radiation Dose Limits, see abovel Ethics, Trade-offs and Medical Radiation by Eugene L. Saenger (1982) [Available also in Radiation Protection and New Medical Diagnostic Approaches, see abovel The Human Environment-Past, Present and Future by Merril Eisenbud (1983) [Available also in Environmental Radioactivity, see abovel Limitation and Assessmnt in Radiation Protection by Harald H. Rossi (1984) [Availablealso in Some Issues Important i n Developing Basic Radiation Protection Recommendations, see abovel Truth (and Beauty) i n Radiation Measurement b y John H. Harley (1985) [Available also in Radioactive Waste, see abovel Biological Effects ofNon-ionizingRadiations: Cellular Properties and Interactions by Herman P. Schwan (1987) [Available also in Nonionizing Electromagnetic Radiations and Ultrasound, see abovel How to be Quantitative about Radiation Risk Estimates by Seymour Jablon (1988) [Available also in New Dosimetry at Hiroshima and Nagasaki and its Implications for Risk Estimates, see above] How Safe is Safe Enough? by Bo Lindell(1988) [Available also in Radon, see above] Radiobiology and Radiation Protection: The Past Century and Prospects for the Future by Arthur C. Upton (1989) [Available also in Radiation Protection Today, see abovel Radiation Protection and the Internal Emitter Saga by J. Newel1 Stannard (1990) [Available also in Health and Ecological Implications of Radioactively Contaminated Environments, see abovel When is a Dose Not a Dose? by Victor P. Bond (1992) [Available also in Genes, Cancer and Radiation Protection, see abovel Dose and Risk i n Diagnostic Radiology: How Big? How Little?by Edward W .Webster (1992)[Availablealso inRadiation Protection i n Medicine, see abovel Science, Radiation Protection and the NCRP by Warren K. Sinclair (1993)[Available also in Radiation Science and Societal Decision Making, see abovel

NCRP PUBLICATIONS

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71

Mice, Myths and Men by R.J. Michael Fry (1995) Symposium Proceedings

No.

Title

1

The Control of Exposure of the Public to Ionizing Radiation in the Event ofAccident orAttack, Proceedings of a Symposium held April 27-29, 1981 (1982) Radioactive and Mixed Waste-Risk as a Basis for Waste Classification, Proceedings of a Symposium held November 9, 1994 (1995)

2

NCRP Statements No.

Title

1

"Blood Counts, Statement of the National Committee on Radiation Protection," Radiology 63, 428 (1954) "Statements on Maximum Permissible Dose from Television Receivers and Maximum Permissible Dose to the Skin of the Whole Body," Am. J. Roentgenol., Radium Ther. and Nucl. Med. 84, 152 (1960) and Radiology 75, 122 (1960) X-Ray Protection Standards for Home Television Receivers, Interim Statement of the National Council on Radiation Protection and Measurements (1968) Specificationof Units ofNatural Uranium and Natural Thorium, Statement of the National Council on Radiation Protection and Measurements (1973) NCRP Statement on Dose Limit for Neutrons (1980) Control of Air Emissions of Radionuclides (1984) The Probability That a Particular Malignancy May Have Been Caused by a Specified Irradiation (1992)

2

3 4

5 6 7

Other Documents The following documents of the NCRP were published outside of the NCRP report, commentary and statement series:

Somatic Radiation Dose for the General Population, Report of the Ad Hoc Committee of the National Council on Radiation Protection and Measurements, 6 May 1959, Science, February 19, 1960, Vol. 131, No. 3399, pages 482-486

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NCRP PUBLICATIONS

Dose Effect Modifying Factors in Radiation Protection, Report of Subcommittee M-4 (Relative Biological Effectiveness) of the National Council on Radiation Protection and Measurements, Report BNL 50073 (T-471) (1967) Brookhaven National Laboratory (National Technical Information Service Springfield, Virginia) The following documents are now superseded andlor out of print:

NCRP Reports No.

Title X-Ray Protection (1931) [Superseded by NCRP Report No. 31 Radium Protection (1934) [Superseded by NCRP Report No. 41 X-Ray Protection (1936) [Superseded by NCRP Report No. 61 Radium Protection (1938) [Superseded by NCRP Report No. 131 Safe Handling of Radioactive Luminous Compound (1941) [Out of Printl Medical X-Ray Protection Up to Two Million Volts (1949) [Superseded by NCRP Report No. 181 Safe Handling of Radioactive Isotopes (1949) [Superseded by NCRP Report No. 301 Recommendations for Waste Disposal of Phosphorus-32 and Iodine-131 for Medical Users (1951) [Out of Printl Radiological Monitoring Methods and Instruments (1952) [Superseded by NCRP Report No. 571 Maximum Permissible Amounts of Radioisotopes i n the Human Body and Maximum Permissible Concentrations in Air and Water (1953) [Superseded by NCRP Report No. 221 Recommendations for the Disposal o f Carbon-14 Wastes , (1953) [Superseded by NCRP Report No. 811 Protection Against Radiations from Radium, Cobalt-60 and Cesium-137 (1954) [Superseded by NCRP Report No. 241 Protection Against Betatron-Synchrotron Radiations Up to 100 Million Electron Volts (1954) [Superseded by NCRP Report No. 511 Safe Handling of Cadavers Containing Radioactive Isotopes (1953) [Superseded by NCRP Report No. 211 Radioactive-Waste Disposal i n the Ocean (1954) [Out of Printl

NCRP PUBLICATIONS

17

18 19 20 21 24 26 28 29 31 33 34 39 43 45 48 53 56 58 66 91

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Permissible Dose from External Sources of Ionizing Radiation (1954) including Maximum Permissible Exposures to Man, Addendum to National Bureau of Standards Handbook 59 (1958) [Superseded by NCFP Report No. 391 X-Ray Protection (1955) [Superseded by NCRP Report No. 261 Regulation of Radiation Exposure by Legislative Means (1955) [Out of Print] Protection Against Neutron Radiation Up to 30 Million Electron Volts (1957) [Superseded by NCRP Report No. 381 Safe Handling of Bodies Containing Radioactive Isotopes (1958) [Superseded by NCRP Report No. 371 Protection Against Radiations from Sealed Gamma Sources (1960) [Superseded by NCRP Reports No. 33,34 and 401 Medical X-Ray Protection Up to Three Million Volts (1961) [Superseded by NCRP Reports No. 33,34, 35 and 361 A Manual of Radioactivity Procedures (1961) [Superseded by NCRP Report No. 581 Exposure to Radiation i n an Emergency (1962) [Superseded by NCRP Report No. 421 * Shielding for High-Energy Electron Accelerator Installations (1964) [Superseded by NCRP Report No. 511 Medical X-Ray and Gamma-Ray Protection for Energies Up to 10 MeV-Equipment Design and Use (1968) [Superseded by NCRP Report No. 1021 Medical X-Ray and Gamma-Ray Protection for Energies Up to 10 MeV-Structural Shielding Design and Evaluation Handbook (1970) [Superseded by NCRP Report No. 491 Basic Radiation Protection Criteria (1971) [Superseded by NCRP Report No. 911 Review of the Current State of Radiation Protection Philosophy (1975) [Superseded by NCRP Report No. 911 Natural Background Radiation in the United States (1975) [Superseded by NCFP Report No. 941 Radiation Protection for Medical and Allied Health Personnel (1976) [Superseded by NCRP Report No. 1051 Review ofNCRP Radiation Dose Limit for Embryo and Fetus i n Occupationally-Exposed Women (1977) [Out of Printl Radiation Exposure from Consumer Products and Miscellaneous Sources (1977) [Supersededby NCRP Report No. 951 A Handbook of Radioactivity Measurements Procedures, 1st ed. (1978) [Superseded by NCRP Report No. 58,2nd ed.1 Mammography (1980) [Out of Print] Recommendations on Limits for Exposure to Ionizing Radiation (1987) [Superseded by NCRP Report No. 1161

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NCRP PUBLICATIONS

NCRP Commentaries No. 2

Title

Preliminary Evaluation of Criteria for the Disposal of Transuranic Contaminated Waste (1982) [Out of Print1 NCRP Proceedings

No. 2

Title

Quantitative Risk in Standards Setting, Proceedings of the Sixteenth Annual Meeting held on April 2-3, 1980 [Out of Print]

Index Absorbed dose 3,8, 42

Exposure 3,44

Air kerma 3 Cancer induction 12-13 estimation by statistical methods 12 from high-dose exposures 12 latency 12-13 Chemical formulation 26-27 Comparative risks 9, 13 Computers and software 8 Contamination control 30-32 air 31 personnel 31-32 surfaces 31 Developmental defects 12 embryolfetus 12 growth retardation 12 malformation 12 mental retardation 12 Dosage 25-30, 43 Dosage calibrations 29-30, 43 activity measurement 29 dosage calibrator 29, 43 periodic calibration 29 reference source check 29 Dose limits 10,45 general public 10 lifetime 10 occupational 10 Dose to patients 20-21 source of exposure to persons nearby 20 source of exposure to public 20 Effective dose 3,43 Effects at low doses 10-11 damage to DNA 11 hereditary 11 somatic 10

Generator eluate 25,26,44 Glossary 42-47 Hereditary defects 11-12 animal species 11 lower forms of life 11 Instrumentation 8 Late effects 11-13, 45 cancer 11-13 mutagenic effects 11-12 teratogenic effects 11-12 Latent period 13,45 dependent variables 13 Low-level radiation doses 9-13 natural background 10 nuclear power 10 occupational 10 public 10 Misadministration 32 Multidose radiopharmaceuticals 25,26 New procedures 8 Nursing mothers 32-33 counseling 32-33 exposure potential to infants 33 radionuclide therapy patients, exposure to 33 restrictions on 32-33 safety considerations 32-33 Organ doses 5

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INDEX

Personnel exposure 19-24 nuclear medicine personnel 19-20 administration to patients 19-20 dosage preparation 19 imaging 19-20 positioning of patient 20 radiopharmacy 19 nurses 21-23 patients 20-21 persons near patients 20-21 public 20-21,23-24 PET 2,8,45 Public significance of nuclear medicine 4-8 diagnosis 4 imaging 4 growth rate 8 metastasis location 4 nature and advantages 4-6 physiological measurement 4 radioimmunoassay 4 size and growth 6-8 therapy 4 Radiation exposure from nuclear medicine practice 19-24 nuclear medicine personnel 19-20 nurses and other medical personnel 2 1-23 general public 23-24 Radiation risk 9-13 comparative risk 9, 13 dose limits 10 effects at low doses 10 low-level doses 9-10 Radiation safety considerations 35-41 collection and handling of excreta 37-39 radiopharmaceutical administration 35 for diagnostic purposes 36-37 for therapeutic purposes 37 notification of 35

staff nurses 35-41 Radioactive materials 14-18 in-house transportation of 15-16 receipt of 15 receipt and delivery of 14-18 shipment of sources 14-15 transport of patients 16-17 transport of specimens 17-18 Radioactive waste disposal 33-34, 46 Radioimmunoassay 4, 46 Radionuclides 5 activity 5 half-life 5 physical characteristics 5 Radiopharmaceuticals 4, 8, 46 Radiopharmaceutical handling procedures 25-34 administration to patient 25, 30 calibration of dosages 25 calibration of stock vials 25 chemical formulation 26-27 compounding and dispensing 25 contamination control 30 imaging 30 iodine diagnosis and therapy 28-29 misadministration 32 radioactive waste disposal 33-34 radiopharmacy 25, 26 safety considerations with nursing mothers 32-33 xenon 27-28 Radiopharmacy 25-26,42 central 42 generator eluate 25 in-house 26 multidose radiopharmaceuticals 25 unit dosage 25,47 Regulation of nucIear medicine 5-6 agreement states 6 FDA 6

NRC 5 Repair 11

INDEX

Repopulation 11 Risk comparisons 9,13

Somatic effects 13 SPECT 2 , 8 , 4 6

Significance of nuclear medicine 4-8 Size and growth of nuclear medicine 6-8

Unit dosages 25,47 Xenon 27-28

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