PHITS - Applications to radiation biology and radiotherapy

Paper in proceeding, 2013

PHITS is a 3-dimensional general-purpose Monte Carlo code, which can transport of all varieties of hadrons and heavy ions with energies up to around 100 GeV/nucleon. To be able to estimate the biological damage from neutrons with PUTTS, a feature has been included to treat low energy neutron collisions as "events" which means that the energy and momentum is conserved in each event and makes it possible to extract the kinetic energy distributions of all the residual nuclei without using any local approximation. To estimate the direct biological effects of radiation, mathematical functions, for calculating the microdosmetric probability densities in macroscopic material, have been incorporated in PUTTS. This makes it possible to instantaneously calculate the probability densities of lineal and specific energies around the trajectories of high energetic charged particle tracks. A method for estimating the biological dose has also been established by using the improved PUTTS coupled to a microdosimetric kinetic model.