应用蒙特卡罗方法计算能量低于3MeV的光子剂量

USING MONTE CARLO METHOD TO SIMULATE TRANSPORT OF PHOTON WITH THE ENERGY LESS THAN 3MeV

目的：用电脑计算在每个物体中每点处点源释放出的原始光子和平均能量损失，以获得光子线在水模体中的剂量分布情况。材料：钴６０机器，长方体的水模体（ＰＨＡＮＴＯＭ），圆柱状钴６０源，直径为２．５厘米，高为２．６厘米。野的范围可从６ｃｍ２取到３０ｃｍ２。方法：蒙特卡罗方法。结果：有两种形式：①研究剂量随深度的变化；②相对剂量（Ｒｅｌａｔｉｖｅｄｏｓｅ）。与Ｐｒｏｗｅｓｓ３０００Ｖｅｒｓ３．０４治疗计划的相应结果比较，此程序所得曲线与Ｐｒｏｗｅｓｓ中曲线基本吻合。结论：本程序应用蒙特卡罗方法模拟能量低于３ＭｅＶ的光子输运具有重要的价值。

Object:Using computer to calculate average energy lost by photons at every points in each body,in order to determine the dose distribution of photon radiation in the water phantom.Material:Cobalt60 teletherapy machine,rectangular water phantom,Co60 source in cylindrical form,diameter is 2.5cm,height is 2.6cm.Radiation fields size vary from 6cm2 to 30cm2.Method:Monte Carlo Method.Results:The result is presented in two forms:①Variation of dose with depth;②Relative dose.The result is compared with Prowess 3000 Vers 3.04 result.It concludes that the curves agree to within and they are very good coordinated.Conclusion:STP program using Monte Carlo Method,has great value to simulate photon transport with the energy less than 3Mev.