Based on a medical treatment schedule for humans, the effects of D-penicillamine and Ca-DTPA on the removal of radiocobalt were examined in rats. Rats were pre-injected with radiocobalt and then treated with D-penicillamine alone via oral route, Ca-DTPA alone via intraperitoneal injection, or both compounds at the same time at doses equivalent to the daily recommended human dose. The compounds were administered for 3 days, beginning with or 1h after radiocobalt injection at the first day. The radioactivity levels of the whole body of rat, urine and feces were measured at intervals of 24h. On day 4, the rats were sacrificed in order to obtain blood and organs. When D-penicillamine was administered with and 1h after injection of radiocobalt, the whole body activity was reduced to 9.6 and 79.0% of that of the control, respectively, in the Ca-DTPA-alone groups and to 54.8% in the group in which both compounds were administered 1h after radiocobalt. In the D-penicillamine-alone groups, the activity levels were reduced to 33.6 and 56.6% with and 1h after radiocobalt injection, respectively. In conclusion, the results of this study indicate that D-penicillamine is useful in treating a person contaminated with radiocobalt in an accident.
To estimate dose from radon progeny, the effective dose per unit exposure to radon progeny (dose conversion factor, DCF) is needed. A dominant parameter related to DCF is the activity size distribution of radon progeny. In the present study, the DCF was calculated in the wide range of particle diameters (0.5-20nm [AMTD] and 20-5, 000nm [AMAD]), using a dosimetric approach. The calculations were based on a computer program, LUDEP, which implements an ICRP66 respiratory tract model. The calculated results showed that the DCF is sensitive to particle size distribution. The DCFs calculated for reference conditions in mines and homes were 13.7mSv WLM-1 and 14.3mSv WLM-1, respectively. These values were in good agreement with those reported in a few references. The DCF calculated in the present study is useful for the dose assessment of radon progeny in places that have different aerosol characteristics.
Effective doses in radius bone mineral density measurements using dual energy X-ray absorptiometry (DEXA) were assessed with entrance beam intensity and X-ray absorption rate in organs. The X-ray entrance beam intensity was calculated from an energy fluence rate, and we demonstrated how to assess beam intensity by using thermoluminescent dosimeters (TLDs). The entrance beam energies were calculated from X-ray beam intensity in regard to beam sizes, scan areas, and scan times. The X-ray absorption rates were calculated by using X-ray absorption curves at bone mineral density measurements. The average tissue doses were determined by using reference female and men. Skin entrance intensity was 4×10-4 [J/(m2·s)]. Skin entrance energies were 1-2×10-3 [J] in proportion to wrist width. The effective dose was approximately 5nSv.
Data base with an electronic text on the safety assessment of low dose ionizing radiation have been constructed. The contents and the data base system were designed to provide useful information to Japanese citizens, radiation specialists, and decision makers for a scientific and reasonable understanding of radiation health effects, radiation risk assessment, and radiation protection. The data base consists of the following four essential parts, namely, ORIGINAL DESCRIPTION, DETAILED INFORMATION, TOPIC INFORMATION, and RELATED INFORMATION. The first two parts of the data base are further classified into following subbranches: Radiobiological effects, radiation risk assessment, and radiation exposure and protection.