Internal dose estimation for inhalation of CsMP

Manabe, Kentaro   ; Matsumoto, Masaki*

When insoluble particles containing radiocesium, CsMP, are incorporated into the body, the radioactivity contained in CsMP does not dissolve in blood or tissue fluid, but migrates through the body in particle form. Since the kinetic behavior of CsMPs in the body is stochastic, the internal dose due to CsMPs is expected to depend on the migration path and to have uncertainty. Therefore, we developed a dose estimation method that simulates the stochastic behavior of insoluble particles such as CsMPs, and evaluated the probability distribution of the effective internal dose due to inhalation of a typical CsMP with a particle size of 2 m. As a result, the ratio of the 99th percentile value to the arithmetic mean of the effective dose distribution for the inhalation of one CsMP was found to be 19, with a very large uncertainty. However, the uncertainty decreased with the increment of the number of simultaneously inhaled CsMPs, and the arithmetic mean of the effective dose was found to be 0.12 mSv and the ratio 1.6 for 10 CsMPs inhaled at the same time.