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 l ow-dose radiation to help institutional review boards and investigator s make educated assessments of the risks of low-level radiation exposu re 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 meas ures and measurement strategies of radiation exposure and of health ri sks, 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 radi ation, radon in homes, radiation in the workplace or radiotherapy, Com pared to the frequency of daily spontaneous genetic mutations, the bio logical effect of low-level radiation at the cellular level seems extr emely low, Furthermore, the potentiation of cellular repair mechanisms by low-level radiation may result in a protective effect from subsequ ent high-level radiation, Studies approved by institutional review boa rds in the U.S. that involve the exposure of healthy normal children t o ionizing radiation were reviewed, Conclusion: Health risks from low- level radiation could not be detected above the ''noise'' of adverse e vents of everyday life, In addition, no data were found that demonstra ted higher risks with younger age at low-level radiation exposure.