A System Utilizing Monte Carlo Calculation Method for Precise Assessment of Dose Distribution in Human Body in Radiation Accidents
F. Takahashi; A. Endo; and Y. Yamaguchi [The Japan Atomic Energy Research Institute (JAERI)]
A radiation accident brings about exposures to ionizing radiation with a significant dose. Dosimetry systems based upon radiation detection instruments or activated elements can give medical staff dose to whole body of a heavily exposed person for a decision of an initial appropriate treatment. On the other hand, dose distribution in body should be clarified for effective medical treatments in the following stage. Monte Carlo calculations have the advantage in analyzing dose distribution inside body, if an appropriate model is established. Then, a numerical system using the MCNP-code is constructed to simulate radiation transport for dose assessments in any accidents. At the first step of this work, a tool was developed to prepare a model of heavily exposed persons for the simulations. A mathematical human model, the MIRD-type phantom, with movable arms and legs can be defined in any body size and postures from information of height, weight and directions of limbs of victims by the tool. The tool can make the input files for sufferers in accidents in a minute based upon the defined MIRD-type phantom. The application of the given human model to a radiation accident was verified with the accident dosimetry, which had been previously performed to analyze dose distribution for heavily exposed workers in the first criticality accident in Japan.