Dependence of simulated positron emitter yields in ion beam cancer therapy on modeling nuclear fragmentation

In ion beam cancer therapy, range verification in patients using positron emission tomography (PET) requires the comparison of measured with simulated positron emitter yields. We found that 1) changes in modeling nuclear interactions strongly affected the positron emitter yields and that 2) Monte Carlo simulations with SHIELD-HIT10A reasonably matched the most abundant PET isotopes 11C and 15O. We observed an ion-energy (i.e., depth) dependence of the agreement between SHIELD-HIT10A and measurement. Improved modeling requires more accurate measurements of cross section values.