Recent improvements in the SHIELD-HIT code

Purpose: The SHIELD-HIT Monte Carlo particle transport code has previously been used to study a wide range of problems for heavy-ion treatment and has been benchmarked extensively against other Monte Carlo codes and experimental data. Here, an improved version of SHIELD-HIT is developed concentrating on three objectives, namely: Enhanced functionality, improved efficiency, and a modification of employed physical models. Methodological developments: SHIELD-HIT (currently at version '10A') is now equipped with an independent detector geometry, ripple filter implementations, and it is capable of using accelerator control files as a basis for the primaries. Furthermore, the code has been parallelized and efficiency is improved. The physical description of inelastic ion collisions has been modified. Results: The simulation of an experimental depth-dose distribution including a ripple filter reproduces experimental measurements with high accuracy. Conclusions: SHIELD-HIT is now faster, more user-friendly and accurate, and has an enhanced functionality with some features being currently unique to SHIELD-HIT. The possibility of data file exchange with existing treatment planning software for heavy-ion therapy allows for benchmarking under treatment conditions as well as extending the capabilities of treatment planning software.