Chen Y, Ahmad S
Department of Radiation Oncology, The University of Oklahoma Health Sciences Center, 825 N.E. 10th Street, Oklahoma City, OK 73104, USA.
Radiat Prot Dosimetry. 2009 Aug;136(1):11-6. doi: 10.1093/rpd/ncp149.
When high-energy protons interact in beam delivery systems and are stopped in patients, a fraction of beam will undergo nuclear interactions that release secondary particles, in particular, neutrons of different energies. The GEANT4 Monte Carlo Code was used to simulate the interaction of 250 MeV proton beam in tissue and iron to calculate the energy and angular distributions of generated protons, neutrons and photons, and thus provide H* (10), the ambient dose equivalent. A modular physics list by utilising electromagnetic interactions and hadronic interactions was constructed. Three different GEANT4 models that include the low-energy parameterisation, binary cascade and pre-compound model with Bertini cascade for proton inelastic interactions were compared. The findings suggest that the models play critical roles in terms of secondary particle generation. Further benchmarks are necessary to select the best model predicting a realistic scenario.
当高能质子在束流传输系统中相互作用并在患者体内停止时，一部分束流会发生核相互作用，释放出次级粒子，特别是不同能量的中子。使用GEANT4蒙特卡罗代码模拟250 MeV质子束在组织和铁中的相互作用，以计算产生的质子、中子和光子的能量和角分布，从而提供周围剂量当量H*(10)。构建了一个利用电磁相互作用和强子相互作用的模块化物理列表。比较了三种不同的GEANT4模型，包括低能参数化模型、二元级联模型和用于质子非弹性相互作用的带有贝蒂尼级联的预复合模型。研究结果表明，这些模型在次级粒子产生方面起着关键作用。需要进一步的基准测试来选择预测实际情况的最佳模型。
