We used the GEANT4 Monte Carlo MC Toolkit to simulate carbon ion beams incident on water, tissue, and bone, taking into account nuclear fragmentation reactions. Upon increasing the energy of the primary beam, the position of the Bragg-Peak transfers to a location deeper inside the phantom. For different materials, the peak is located at a shallower depth along the beam direction and becomes sharper with increasing electron density NZ. Subsequently, the generated depth dose of the Bragg curve is then benchmarked with experimental data from GSI in Germany. The results exhibit a reasonable correlation with GSI experimental data with an accuracy of between 0.02 and 0.08 cm, thus establishing the basis to adopt MC in heavy-ion treatment planning. The Kolmogorov-Smirnov K–S test further ascertained from a statistical point of view that the simulation data matched the experimentally measured data very well. The two-dimensional isodose contours at the entrance were compared to those around the peak position and in the tail region beyond the peak, showing that bone produces more dose, in comparison to both water and tissue, due to secondary doses. In the water, the results show that the maximum energy deposited per fragment is mainly attributed to secondary carbon ions, followed by secondary boron and beryllium. Furthermore, the number of protons produced is the highest, thus making the maximum contribution to the total dose deposition in the tail region. Finally, the associated spectra of neutrons and photons were analyzed. The mean neutron energy value was found to be 16.29 MeV, and 1.03 MeV for the secondary gamma. However, the neutron dose was found to be negligible as compared to the total dose due to their longer range.

我们使用 GEANT4 Monte Carlo MC Toolkit 来模拟入射到水、组织和骨骼上的碳离子束，同时考虑到核碎裂反应。在增加主光束的能量后，布拉格峰的位置转移到体模内部更深的位置。对于不同的材料，峰位于沿束流方向较浅的深度处，并且随着电子密度 NZ 的增加而变得更尖锐。随后，生成的布拉格曲线深度剂量随后与来自德国 GSI 的实验数据进行基准测试。结果显示出与 GSI 实验数据的合理相关性，精度在 0.02 至 0.08 cm 之间，从而为在重离子治疗计划中采用 MC 奠定了基础。Kolmogorov-Smirnov K-S 检验从统计的角度进一步确定，模拟数据与实验测量数据非常吻合。将入口处的二维等剂量轮廓与峰值位置周围和峰值以外的尾部区域中的轮廓进行比较，表明与水和组织相比，由于二次剂量，骨骼产生了更多的剂量。在水中，结果表明每个碎片沉积的最大能量主要归因于次级碳离子，其次是次级硼和铍。此外，产生的质子数量最多，因此对尾部区域的总剂量沉积贡献最大。最后，分析了中子和光子的相关光谱。发现平均中子能量值为 16.29 MeV 和 1。03 MeV 用于二级伽马。然而，发现中子剂量与总剂量相比可忽略不计，因为它们的射程更长。