Evaluation of the effect of dose rate and dose absorption on the long-term radiation consequences in rats chronically taking in 90Sr

The effects of exposure to 90Sr which was given with food with daily doses 18.5 kBq per animal for 1-12 months, 37 kBq per animal for 1-10 months, 74 kBq per animal for 1-8 months and 148 kBq per animal for 1-6 months on mortality patterns in unimbred white rats were investigated. Hazard models were used to evaluate dose rate and accumulated dose influence on radiation-related trends in mortality. The time-dependent risk of death from all causes and from osteosarcomas depended on the dose rate. The risk of death from causes other than osteosarcoma depended on the dose rate and the accumulated dose. To predict time-dependent risk of death it was better to use the least time to calculate the dose rate--1 day.