摘要
The effectiveness of heavy ion therapy has attracted global attention. Taiwan's first heavy ion therapy center, which has started clinical treatments in May 2023, is the 14th operational heavy ion therapy center in the world. This study used a tissue-equivalent proportional counter (TEPC) to assess the microdosimetric parameters of three different energy beams at the heavy ion facility, in order to evaluate representative beam quality indicators such as the relative RBE (Radiation Biological Effectiveness) of the heavy ion radiation field. The maximum absorbed dose for the three energy beams were found to occur at the dmax (Bragg peak) position. After the dmax, secondary particles continue to deposit energy at deeper depths, but clinical treatment planning systems may overlook the dose contribution from these secondary particles. The effective RBE values of all three energy beams at their respective dmax positions were found to be not necessarily the highest. The effective RBE values for the evaluated heavy ion therapy facility ranged from approximately 3.1 to 3.4. The evaluation methods and related results of this study can serve as a reference for dose assessment in clinical heavy ion therapy centers.