Aminafshar Behzad, Baghani Hamid Reza, Mowlavi Ali Asghar
Physics Department, Hakim Sabzevari University, Daneshgah Blvd, P.O. 9617976487, Sabzevar, Iran.
Radiol Phys Technol. 2025 Mar;18(1):300-307. doi: 10.1007/s12194-024-00864-0. Epub 2024 Dec 5.
Determination of spread-out Bragg peak (SOBP) inside media other than water is important for research or clinical purposes. Current study aims to characterize the optimal "p" values needed for the simulation of proton SOBP inside some dosimetry media using MCNPX Monte Carlo code. Following the provided data by ICRU-49 and applying the Bortfeld and Jette recommendations, the "p" values were determined for muscle, compact bone, and PMMA. Then, "p" values were optimized to reach accurate weight fractions for the Monte Carlo simulation of SOBP curves. Obtained optimal "p" values can produce accurate proton weight fractions for flat SOBP simulation. The slope of the SOBP region was highly dependent on the "p" value, so small changes in this parameter can largely tilt up or down the SOBP. The tabulated optimal "p" values can be reliably used for proton weight fraction determination during the Monte Carlo simulation of the proton beam SOBP curve inside the investigated media.
确定除水以外的介质中的扩展布拉格峰（SOBP）对于研究或临床目的很重要。当前的研究旨在表征使用MCNPX蒙特卡罗代码模拟某些剂量学介质中质子SOBP所需的最佳“p”值。根据ICRU - 49提供的数据并应用博尔特费尔德和杰特的建议，确定了肌肉、密质骨和聚甲基丙烯酸甲酯的“p”值。然后，对“p”值进行优化，以获得用于SOBP曲线蒙特卡罗模拟的准确权重分数。获得的最佳“p”值可用于平面SOBP模拟产生准确的质子权重分数。SOBP区域的斜率高度依赖于“p”值，因此该参数的微小变化会使SOBP大幅向上或向下倾斜。列出的最佳“p”值可可靠地用于在所研究介质中质子束SOBP曲线的蒙特卡罗模拟期间确定质子权重分数。
