The presence of the Bragg peak and its use in proton therapy cause less damage to healthy tissues. For optimal use of the proton beam in proton therapy, it is necessary to monitor the deviation of its range during treatment. The prompt gamma rays originated from the nuclear reactions of the proton beam with tissue elements can be applied for this purpose. The spatial distribution of prompt gamma rays can be used to estimate the range of the incident charged particles. Detecting a wide energy range of gamma rays, up to 10 MeV, is the most challenging step of the proton dose verification by using prompt gamma spectroscopy. Compton suppression is a system that is used to reduce the contribution of scattered gamma rays. This technique will cause better detection of the peaks of low-energy prompt gamma rays. In this research, the performance of a Compton suppression system has been investigated in two fields for proton therapy and for elemental analysis of materials using isotopes by a wide range of gamma energies. At first, by using the simulated Compton suppression system, the calculations of the prompt gamma ray spectra emitted from the brain phantom during the radiation of 150 MeV protons were presented. The results indicated that the low energy elements peaks such as 40Ca (1.37 MeV) with CSF equal to 1.138 appeared in the suppressed spectrum. Also, it was possible to detect 14N (2.31 MeV) and 16O (6.13 MeV) peaks equivalent to the CSF 2.449 and 2.067 respectively. In the next step, it was possible to detect the low energy peaks of 152Eu and 155Eu isotopes in the suppressed spectrum. For this purpose, the minimum relative intensity required to detect all 152Eu and 155Eu peaks was equivalent to 0.001 and 0.002 respectively. CSF for the lowest energies such as 105 keV and 344 keV was equal to 1.169 and 1.184. The simulation was done using the GEANT4 Monte-Carlo toolkit.

中文翻译：

---

康普顿抑制伽马射线能谱法用于质子治疗应用的可行性


布拉格峰的存在及其在质子治疗中的应用对健康组织造成的损害较小。为了在质子治疗中最佳使用质子束，有必要在治疗过程中监测其范围的偏差。源自质子束与组织成分的核反应产生的瞬发伽马射线可用于此目的。瞬发伽马射线的空间分布可用于估计入射带电粒子的范围。使用瞬发伽马能谱法检测高达 10 MeV 的宽能量范围伽马射线是质子剂量验证中最具挑战性的步骤。康普顿抑制是一种用于减少散射伽马射线贡献的系统。该技术将更好地检测低能瞬发伽马射线的峰值。在这项研究中，康普顿抑制系统的性能已在质子治疗和使用宽范围 γ 能量的同位素对材料进行元素分析的两个领域进行了研究。首先，通过使用模拟的康普顿抑制系统，提出了 150 MeV 质子辐射过程中脑体模发射的瞬发伽马射线谱的计算结果。结果表明，低能量元素峰，如 40Ca （1.37 MeV），CSF 等于 1.138，出现在抑制光谱中。此外，还可以检测到分别相当于 CSF 2.449 和 2.067 的 14N （2.31 MeV） 和 16O （6.13 MeV） 峰。在下一步中，可以在抑制光谱中检测到 152Eu 和 155Eu 同位素的低能峰。为此，检测所有 152Eu 和 155Eu 峰所需的最小相对强度分别相当于 0.001 和 0.002。 最低能量（如 105 keV 和 344 keV）的 CSF 等于 1.169 和 1.184。模拟是使用 GEANT4 Monte-Carlo 工具包完成的。