Particle diameter dependence of internal doses due to inhalation of insoluble cesium particles

Manabe, Kentaro   ; Matsumoto, Masaki*

When an insoluble cesium-bearing particle which has high specific activity is inhaled into the human body, the activity will move stochastically in the state of a sphere without dissolving in the blood or tissue fluid. We have developed a stochastic biokinetic method to evaluate the stochastic behavior of the particle in the body and estimated the probability distribution of exposure doses from a typical cesium-bearing particle whose diameter is 2 m. In this study, we analyzed particle diameter dependence of dose distribution due to inhalation of the particle with considering that the activity in a particle and the deposition probability to the regions of the respiratory tract change with the diameter. As a result, the maximal values of 99%ile values and arithmetic means were observed at 3.0 m and 3.5 m, respectively.