Health hazards of radiation exposure in the context of brain imaging research: special consideration for children.
This review provides information on health and biological effects of low-dose radiation to help institutional review boards and investigators make educated assessments of the risks of low-level radiation exposure involved in research, particularly in children.


METHODS
Studies of low-level radiation exposure with large sample sizes and long follow-up were reviewed. To help interpret the studies, we clarified the measures and measurement strategies of radiation exposure and of health risks. The few large studies of risks of low-level radiation in children have failed to detect an increased incidence of cancer. Most studies of low-level radiation involve adults.


RESULTS
The risk of increased rates of cancer after low-level radiation exposure is not supported by population studies of health hazards from exposure to background radiation, radon in homes, radiation in the workplace or radiotherapy. Compared to the frequency of daily spontaneous genetic mutations, the biological effect of low-level radiation at the cellular level seems extremely low. Furthermore, the potentiation of cellular repair mechanisms by low-level radiation may result in a protective effect from subsequent high-level radiation. Studies approved by institutional review boards in the U.S. that involve the exposure of healthy normal children to ionizing radiation were reviewed.


CONCLUSIONS
Health risks from low-level radiation could not be detected above the "noise" of adverse events of everyday life. In addition, no data were found that demonstrated higher risks with younger age at low-level radiation exposure.
Ernst
M
M
Brain Imaging Center, National Institute on Drug Abuse, Baltimore, Maryland 21224, USA.
Freed
M E
ME
Zametkin
A J
AJ
D001921:Brain / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D002648:Child; D004781:Environmental Exposure; D006801:Humans; D011829:Radiation Dosage; D011877:Radionuclide Imaging; D011878:Radiotherapy; D011886:Radon / Q000009:adverse effects; D012307:Risk Factors
D011886:Radon