Ionizing radiation exposure dose

Hazelton, W. D., Moolgavkar, S. H., Curtis, S. B., Zielinski, J. M., Ashmore, J. P, and Krewski, D. (2006). Biologically based analysis of lung cancer incidence in a large Canadian occupational cohort with low-dose ionizing radiation exposure, and comparison with Japanese atomic bomb survivors. J Toxicol Environ Health Part A 69, 1013-1038. 

Mostly natural sources contribute to the ionizing radiation exposure that people undergo aU the time. The received dose of radiation is measured in grays. The absorbed dose of radiation that results in damage done to organisms is measured in sieverts. 

Fig. 9 CL determinations of the modification in pol)oirethane coating material induced by ionizing radiation exposure. Temperature 170 °C environment air. The data were taken from [lOPl]. (a) CL curves recorded on PUR after y-irradiation in air at different total doses. (1) unirradiated sample (2) 9.6 kGy (3) 28.8 kGy (4) 59.2 kGy.(b) Oxidation rates on propagation stage for oxidation of various sample formulations (base material/hardener).(white) 3 1, (black) 4 1, (grey) 5 1.

Radiation Dosimetry. Radioactive materials cause damage to tissue by the deposition of energy via their radioactive emissions. Thus, when they are internally deposited, all emissions are important. When external, only those emissions that are capable of penetrating the outer layer of skin pose an exposure threat. The biological effects of radiation exposure and dose are generally credited to the formation of free radicals in tissue as a result of the ionization produced (17). 

Is the employer using means other than employee rotation to eomply with permissible exposure limits (PELs) or ionizing radiation dose limits, exeept where no other feasible way exists [OSHA Referenee. 120(g)(l)(iii)]... 

Epidemiological and Human Dosimetry Studies. Epidemiological studies of radiation dose typically involve estimates of exposure that are based on whole-body measurements of internally-deposited americium. A need remains for epidemiological data that can provide quantitative human dose-response information while supplying additional information on the health effects of exposure to ionizing radiation and americium in particular, for cases of known internal exposure. 

Radiation is carcinogenic. The frequency of death from cancer of the thyroid, breast, lung, esophagus, stomach, and bladder was higher in Japanese survivors of the atomic bomb than in nonexposed individuals, and carcinogenesis seems to be the primary latent effect of ionizing radiation. The minimal latent period of most cancers was <15 years and depended on an individual s age at exposure and site of cancer. The relation of radiation-induced cancers to low doses and the shape of the dose-response curve (linear or nonlinear), the existence of a threshold, and the influence of dose rate and exposure period have to be determined (Hobbs and McClellan 1986). 

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