Low Dose Radiation Cancer Risks: Epidemiological and Toxicological Models
The basic purpose of this one year research grant was to extend the two stage clonal expansion model (TSCE) of carcinogenesis to exposures other than the usual single acute exposure. The two-stage clonal expansion model of carcinogenesis incorporates the biological process of carcinogenesis, which involves two mutations and the clonal proliferation of the intermediate cells, in a stochastic, mathematical way. The current TSCE model serves a general purpose of acute exposure models but requires numerical computation of both the survival and hazard functions. The primary objective of this research project was to develop the analytical expressions for the survival function and the hazard function of the occurrence of the first cancer cell for acute, continuous and multiple exposure cases within the framework of the piece-wise constant parameter two-stage clonal expansion model of carcinogenesis. For acute exposure and multiple exposures of acute series, it is either only allowed to have the first mutation rate vary with the dose, or to have all the parameters be dose dependent; for multiple exposures of continuous exposures, all the parameters are allowed to vary with the dose. With these analytical functions, it becomes easy to evaluate the risks of cancer and allows one to deal with the various exposure patterns in cancer risk assessment. A second objective was to apply the TSCE model with varing continuous exposures from the cancer studies of inhaled plutonium in beagle dogs. Using step functions to estimate the retention functions of the pulmonary exposure of plutonium the multiple exposure versions of the TSCE model was to be used to estimate the beagle dog lung cancer risks. The mathematical equations of the multiple exposure versions of the TSCE model were developed. A draft manuscript which is attached provides the results of this mathematical work. The application work using the beagle dog data from plutonium exposure has not been completed due to the fact that the research project did not continue beyond its first year.
- Research Organization:
- Medical Univ. of South Carolina, Charleston, SC (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-08ER64605
- OSTI ID:
- 1043283
- Report Number(s):
- Final Technical Report; TRN: US1204360
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION
ACUTE EXPOSURE
BEAGLES
CARCINOGENESIS
LUNGS
MUTATIONS
NEOPLASMS
PLUTONIUM
PROLIFERATION
RADIATIONS
RETENTION FUNCTIONS
RISK ASSESSMENT
Low-dose radiation
Cancer