Around the Nuclear World 153

radionuclides has also decreased, in spite of their increased use, particularly in medical procedures, a reflection perhaps of increased awareness and enforcement of safety practices. In contrast, the inci- dence of accidents associated with sealed sources is increasing. Several factors, including variable training practices, the increasing number and the mobility of radiographers, and the nature and location of the operations in which they are engaged, contribute to the frequency of these accidents. An important additional factor appears to be in the mechanical design of radiography cameras. However regretable and noteworthy radiation accidents may be, the incidence of significant acciden- tal radiation doses to individuals (an annual average of 3.3 for 1975-1977 in the U.S.A.) should be seen in the context of the incidence of injuries from all causes (an annual average of 70,420,OOO for 197551977 in the U.S.A.).“’

References

1. FRY S. A. The U.S. Radiation Accident and other registries of the REACTS system: their function and current status. In The Medical Basis for Radiation Accident Preparedness; Proceed- ings of an International Conference, Oak Ridge, Tenn., 1979 (Edited by HUBNER K. F. and FRY S. A.). Elsevier/North-Holland. In press.

2. Accident Facts, 1979 edn. National Center for Health Statistics, Washington, D.C.

Clinical Effects of Radiation: A Symposium Discussion

Dr H. L. Berman: I have a comment concerning the use of the term “radiation burn” and a question. The term “radiation burn” ought not to be used, chiefly because of the implication of negligence on someone’s part. It would be better to use “radiation dermatitis--first, second, third, or fourth degree (l”, 2”, 3”. 4”); or “radiation reaction” qualified by a descriptive term of moderate erythema or necrosis as may be appropriate. My question to Dr Fry concerns the incidence of hypothyroidism in the Marshallese Islanders and the estimated doses to thyroids of this group.

Dr Fry: I understand Dr Berman’s concern in that the term “burn” particularly not be used in the context of the therapeutic use of radiation where a degree of radiation reaction might be acceptable or planned for. However, I believe it may be difficult to eliminate the term from the lexicon of those involved in the treatment of accidental high dose local exposures. To answer your question: Dr Robert Conard reported recently that there is positive evidence of thyroid hypofunction in 14 of 244 inhabitants of the Marshall Islands and evidence suggestive of thyroid hypofunction in 14 other individuals in the same population. Reevaluation of the exposures to this population gave an estimated dose to the thyroid of children under the 10 years at the time of the accident of between 700 and 1400 rad and of about 325 rad to the thyroids of the more heavily exposed adults.

Dr Katz: Should the worker who has recovered from an acute high level total body exposure to radiation be allowed to continue in a job that involves radiation?

Dr Andrews: This is a problem that involves legal and management aspects as well as biological consideration. If the job is properly set up, with exposures well within the occupationally accepted limits, and if we know that there is no reasonable likelihood of a repetition of the accident, the person could reasonably return to work with very low levels of radiation. This might be particularly appro- priate if he has a high level of training invested in this field. If we assume that the risk of late effects is essentially linear with dose, a minute amount of added dose, while increasing the risk slightly, should not have any greater absolute effect than it would without the previous accidental dose. Of course, if the patient has been involved in a chronically hazardous and poorly managed job in industrial radiography, every effort should be made to prevent him from returning to a similar situation. Each case is an individual decision and psychological factors are important.

Dr H. C. Allen: It is very difficult to stop industrial radiographers from returning to work given the ‘mobility required by their occupation.

154 Around thr Nuclear World

Mr S. Harris: As a health physicist, I have been involved in radiation protection both as a regulator and as a regulatee and have observed severe radiation damage to the hands; for instance, 1 out of 3 veterinarians work in radiation fields with bare hands. Is there a registry for the effects of these chronic exposures to the hands?

Dr D. C. White: No, thereis not. I do not know why not; it would be useful to have [such a registry].

Unsigned: If an autologous or matched bone marrow transplant might be lifesaving in the event of an accidental high dose total body irradiation, would it be realistic to maintain bone marrow banks for those [persons] who are at risk?

Dr G. A. Amhews: It would be theoretically possible but not practical.

Dr V. P. CoUIns: I have a comment in reference to return to work after overexposure to radiation. Medically, one can approve; but successive employers would be reluctant to hire since they, or their insurers, might be expected to share in ultimate compensation should a condition develop which might be attributed to radiation exposure during any previous employment.

Dr R. C. Garcia: Have any of the survivors of radiation accidents since died of other causes?

Dr Fry: Yes. At REAC/IS we know of the deaths of 68 Marshall Islanders between 1955 and 1979; so far, we know the cause of only 2 of these deaths; 1 was an individual, 1 year old at the time of exposure, who died of acute myelogeneous leukemia at the age of 19. The second known cause was carcinoma of the stomach. Five of the 8 survivors of the early Los Alamos accidents are known to have died, 2 from leukemia; 1, with a history of myxedema and hypercholesterolemia, had a second and fatal myocardial infarction. One died about 30 years after the accident of bacterial endocarditis; he had an underlying erythroid dysplasia; he was 83 years old. The fifth individual was killed while on active service during the Korean War. Two of the 8 individuals involved in the accident at Oak Ridge in 1958 have since died. One, a heavy smoker and underground coal miner, died of a metastatic bronchogenic carcinoma in 1972; the other died of a cerebrovascular accident at age 76 as did one of the survivors of the 1961 Lockport accident who died at age 69.

Dr Prodmxka: Have there been any congenital malformations or birth defects among the children of persons accidentally exposed to high total body doses of radiation? And have there been.any reports of studies of the health status of children of radiologists in the United States?

Dr Fry: We are not aware of any congenital malformations or other birth defects in the children of the survivors of radiation accidents that we have studied. With regard to the children of radiologists, I know there was a paper published recently updating the study of the radiologists themselves, but I do not think that the results of the study of the children have as yet been published.

Summary-Dr Fry: Dr Allen, in his presentation opening this first session of the meeting, has deflned the multifaceted problem of radiation and public health. In doing so he has described as one of the larger facets, the problem of the public and the public’s conception, or in some cases, misconception, of radiation and its effects. The informed physician, particularly the radiologist, radiotherapist, and nuclear medicine specialist, as a trusted interpreter of the situation, real or anticipated, has an important role to play in alleviating the aspects of the problem that are rooted in lack of education or understanding about the subject and lack of communication between those in a position to know and those with a need to know. Subsequent papers have dealt with the pathological and clinical effects of acute exposures to relatively high doses of ionizing radiation and the circumstances in which such doses have been incurred accidentally. In contrast to the effects of exposure to low doses at low dose rates, the effects of these high dose exposures have been shown to be predictable in relation to dose and type of exposure; their severity and duration are related directly to dose and, given modern therapeutic methods, they are survivable, even with doses in the region of 1000 rad. However trauma- tic physically and psychologically such events and injuries mighi be, their low incidence rate should be put into perspective with the other risks that we face daily; and, at the same time, efforts to reduce their incidence even further must continue through training and technological improvements.