点辐射场中骨微观结构对其能量沉积特性的影响

Influences of bone microstructure in point radiation field on energy deposition characteristics

目的:由于骨微观结构复杂,难以进行数字化建模,在进行模拟计算时多用简单模型代替真实模型。针对这一现状,我们运用蒙特卡罗方法通过简单模型模拟不同骨微观结构中红骨髓的能量沉积,以评估该方法的合理性。方法:运用蒙卡软件,采用单一变量原则,建立一系列单腔体到多腔体骨模型,模拟伽马射线在该结构中的输运过程,分别分析对比光子能量相同时在不同模型中红骨髓的能量沉积和光子能量不同时在相同模型中红骨髓的能量沉积。结果:光子能量相同时,在不同模型中红骨髓的能量沉积基本持平;光子能量不同时,在相同模型中红骨髓的能量沉积随着光子能量的增加成递增趋势。结论:在其他条件相同的情况下,辐射所致红骨髓剂量主要取决于辐射源的能量;在源能量相同的情况下,骨髓模型对红骨髓的影响较小,因此初步论证了在做骨髓剂量模拟时可用简单模型代替真实模型。

Objective Bone microstructure is complex and difficult to establish digital model, so the simple model is always applied in the simulation calculation, instead of real model. In order to validate its rationality, based on simple models, Monte Carlo method is used to simulate the energy deposition of red marrow in different bone microstructures. Methods Based on the principle of single variable, Monte Carlo software was applied to establish a series of bone structure models from single-cavity to multi-cavity, simulating the transport process of the gamma rays. The energy deposition of red marrow in different models with the same photon energy, and the energy deposition of red marrow in the same model with different photon energies were analyzed and compared. Results With the same photon energy, the energy deposition of red marrow in different models were basically fiat. However, the energy deposition of red marrow in the same model increased with the increased photon energy. Conclusion With the same conditions, the red marrow dose caused by radiation mainly depends on the energy of the radiation source. With the same source energy, the red marrow model has less effect on the energy deposition. It is preliminarily demonstrated that the simple model can replace the real model in marrow dose simulation.