Cancer from radiation exposure

Health effects other than cancer from radiation exposure are not likely when the dose to the unborn baby is very low. 

After the nuclear explosion at Chernobyl in 1986, Anatoly and other professors and physicians created a foundation, For the Children of Chernobyl. Their goal was to send children abroad for the summers for a reprieve from radiation exposure which impairs their immune systems and has resulted in unprecedented levels of thyroid cancer in children and adults. The first host country to respond to their call for help was India. Before long, the foundation was sending 30,000 children every summer to host families and programs in many countries, including Germany, England, Japan, the U.S., Spain, Italy and France. 

ICRP (1991) has acknowledged that the modifications of the probability of a fatal response are necessarily judgmental and somewhat arbitrary, particularly the weight to be given to nonfatal cancers relative to fatal responses in assessing total detriment. Nonetheless, the following approach to assessing total detriment from radiation exposure for purposes of radiation protection was developed. 

Stather, J.W., Wrixon, A.D. Simmonds, J.R. (1984) The risks of leukaemia and other cancers in Seascale from radiation exposure. National Radiological Protection Board Report R-171, HMSO, London. 

No evidence linking oral exposure to uranium to human cancer has been found. Although natural, depleted, or enriched uranium and uranium compounds have not been evaluated in rodent cancer bioassays by any route by the NTP (BEIR 1980, 1988, 1990 Hahn 1989 Sanders 1986 UNSCEAR 1982,1986,1988), there is potential for the carcinogenicity of uranium, since it emits primarily alpha radiation. Nevertheless, no evidence has been found to associate human exposure to uranium compounds and carcinogenesis. The National Academy of Sciences has determined that bone sarcoma is the most likely cancer from oral exposure to uranium however, their report noted that this cancer has not been observed in exposed humans and concluded that exposure to natural uranium may have no measurable effect (BEIR IV). 

Table V. Cancer Risks from Radiation Exposures ...

The performance of a diagnostic X-ray machine should be checked at least annually with appropriate instruments by a qualified person. If the capability to do this is not available in-house, a qualified consultant should be hired to do the task. If any maintenance is done or if the machine is relocated, a survey should be undertaken for leakage radiation fromthe source. If the unit is moved to another facility, the exposure levels in the adjacent areas should be tested to ensure that the exposure levels are within the permissible limits forcontrolled and uncontrolled areas. Records of all maintenance, surveys, leakage checks, calibration, personnel monitoring, etc. should be maintained at the facility and at the radiation safety office. Because of the long latency period for cancer developing from radiation exposures, it would not be unreasonable to maintain personnel exposure records for up to 40 years. 

Brenner, David, and Eric Hall. Computed Tomography An Increasing Source of Radiation Exposure. New England Journal of Medicine S57, no. 22 (2007) 2277-2284. An analytical overview of the use of CT and the risk of cancer induction from radiation exposure. Illustrations and statistical data on various CT procedures. 

Most of the data on radiation health effects have come from medical monitoring of Japanese atomic bomb survivors. For survivors who received radiation exposures up to 0.10 Sv, the iacidence of cancer is no greater than ia the geaeral populatioa of Japanese citizens. For the approximately 1000 survivors who received the highest radiation doses, ie, >2 Sv, there have been 162 cases of cancer. About 70 cases would have been expected ia that populatioa from aatural causes. Of the approximately 76,000 survivors, as of 1995 there have beea a total of about 6,000 cases of cancer, only about 340 more cases than would be expected ia a group of 76,000 Japanese citizens who received only background radiation exposure (59). 

It should be noted that there is intense controversy as to the health effects of radiation doses below about 100 mSv per year. This estimate of 15,000 annual cancer deaths from indoor radon, as well as estimates of tens of thousands of eventual cancer deaths from Chernobyl exposures, is obtained by applying the linearity hypothesis. This hypothesis has been adopted by most regulatory agencies but is strongly contested by some scientists who believe it overestimates the effects of radiation at low dose levels. Of course, if calculations based on this hypothesis overestimate the deaths from indoor radon, they also overestimate the effects of potential radiation from a waste repository. 

The calculation of effective dose equivalent is sometimes used even when reporting values for natural radioactivity. The concept of effective dose equivalent was developed for occupational exposures so that different types of exposure to various organs could be unified in terms of cancer risk. It is highly unlikely that the general population would require summation of risks from several sources of radiation exposure. 

Archer, V.J., Oncology Overview, Selected Abstracts on Risk of Cancer from Exposure to Low Level Ionizing Radiation, PB84-922906, International Cancer Research Data Bank Program, National Cancer Institute, U.S. Department of Health and Human Services, Salt Lake City, Utah, (August 1984) ... 

Calculation of lung cancer risk for radon daughter exposure is based on factors developed by the National Council on Radiation Protection and Measurements (NCRP, 1984). The risk coefficients are expressed in terms of lifetime risk from lifetime exposure for a population of mixed ages, comparable to the standardized U.S. population, and range between one and two per 10,000 WLM of exposure. The percent increase in risk is related to a normal lifetime lung cancer risk of 0.041. 

Mancuso, T.F., Stewart, A., and Kneale, G., Radiation exposures of Hanford workers dying from cancer and other causes, Health Physics, 33, 369-385, 1977. 

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