Monte Carlo codes have been used for approximately 80 years to solve various problems in medical physics. In this paper, the importance of the MCNPX code in treatment planning is highlighted. As illustrative examples of the role of MCNPX in this field, some dosimetric parameters, isodose distribution curves, and figures of merit (FOMs) were considered for photon beams of various energies. To the best of the authors' knowledge, such a systematic study has not been done before. Tissue-air ratio values were obtained as a function of depth in tissue as well as field size. The results of the simulations were in agreement within 3.5% with experimental results reported in the literature. Backscatter factor values were calculated as a function of beam energy, and found to be in agreement with published experimental values within 5.9%. The isodose curves for different conditions and beam arrangements were also simulated. Besides, FOMs were calculated for different radiation energies. All the results were in agreement with related data in the literature. It is concluded that the MCNPX code and the models developed in the present study can be used in different conditions where these parameters are involved, improving individualized treatment planning for individual patients.

中文翻译：

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MCNP模拟在治疗计划中的应用：一项比较研究。

蒙特卡洛代码已经使用了大约80年，以解决医学物理学中的各种问题。在本文中，强调了MCNPX代码在治疗计划中的重要性。作为MCNPX在该领域中作用的说明性示例，考虑了各种能量的光子束的一些剂量学参数，等剂量线分布曲线和品质因数（FOM）。据作者所知，以前从未进行过这样的系统研究。获得的组织空气比值是组织深度和视野大小的函数。模拟结果与文献报道的实验结果相吻合在3.5％以内。计算后向散射因子值是光束能量的函数，并发现与公布的实验值相符（在5.9％以内）。还模拟了不同条件和光束布置的等剂量线。此外，还针对不同的辐射能量计算了FOM。所有结果与文献中的相关数据一致。结论是，本研究中开发的MCNPX代码和模型可以在涉及这些参数的不同条件下使用，从而改善了个别患者的个性化治疗计划。