Monte Carlo calculated stopping power ratio water/air for clinical proton therapy
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文摘
In order to compute stopping-power ratios water/air for use in clinical proton dosimetry a Monte Carlo code has been developed. The main difference between the present code and other codes for proton transport is the inclusion of the detailed production of secondary electrons along the proton track. For this purpose the code is a Class-II type, where single proton-electron collisions yielding energy losses larger than a specific cut-off are considered individually. Proton multiple scattering is sampled from the complete Moliére distribution. To take into account in an approximate way the effect of inelastic nuclear collisions the fraction of the incident energy that is converted to kinetic energy of charged particles in the interaction is deposited on the spot. The energy that goes to neutral particles is assumed to leave the scoring geometry without any energy deposition.