Helium ions for radiotherapy? Physical and biological verifications of a novel treatment modality
Helium ions for radiotherapy? Physical and biological verifications of a novel treatment modality
复制标题
DOI：
10.1118/1.4944593
复制
发表时间：
2016-04-01
期刊：
影响因子：
3.8
通讯作者：
Durante, Marco
中科院分区：
文献类型：
--
作者：
Kraemer, Michael;Scifoni, Emanuele;Durante, Marco
目的：主动扫描离子束放射治疗的现代设备原则上允许使用氦束，它可以显示出特定的优势，特别是对儿童肿瘤。为了评估这些光束在放射治疗中的潜在用途，即创建现实的治疗计划，作者建立了一个专用的He-4光束模型，为他们的治疗计划系统TRiP98提供基础数据，他们在这项工作中报告了其物理和生物学验证。方法：在TRiP98中建立并介绍了物理深度剂量沉积和核碎片产生的半经验光束模型。对于生物效应计算，使用了最新版本的局部效应模型。模型的预测在HIT设施得到了实验验证。利用200 MeV/u的氦-4离子束，研究了水中不同深度的一次束流衰减和二次带电粒子的特性。利用Delta E/E望远镜确定了次级碎片的核电荷。利用针点电离室测量了三维吸收剂量分布，并对排列成扩展靶的中国仓鼠卵巢细胞进行了生物剂量测定实验。结果：基本物理过程的少量实验数据可以用光束模型进行再现。对扩大靶体积中吸收剂量分布的实验验证得出了总体一致的结果，但对横向扩散的估计略有低估。细胞存活沿着一个4厘米的扩展靶是复制具有显著的准确性。结论：作者提出了一个简单的治疗性He-4光束的模拟模型，并通过物理和生物剂量学的方法进行了实验验证。因此，现在有可能用He-4光束进行详细的治疗计划研究，无论是单独的还是与其他离子模式相结合。(C) 2016。
Purpose: Modern facilities for actively scanned ion beam radiotherapy allow in principle the use of helium beams, which could present specific advantages, especially for pediatric tumors. In order to assess the potential use of these beams for radiotherapy, i.e., to create realistic treatment plans, the authors set up a dedicated He-4 beam model, providing base data for their treatment planning system TRiP98, and they have reported that in this work together with its physical and biological validations.Methods: A semiempirical beam model for the physical depth dose deposition and the production of nuclear fragments was developed and introduced in TRiP98. For the biological effect calculations the last version of the local effect model was used. The model predictions were experimentally verified at the HIT facility. The primary beam attenuation and the characteristics of secondary charged particles at various depth in water were investigated using He-4 ion beams of 200 MeV/u. The nuclear charge of secondary fragments was identified using a Delta E/E telescope. 3D absorbed dose distributions were measured with pin point ionization chambers and the biological dosimetry experiments were realized irradiating a Chinese hamster ovary cells stack arranged in an extended target.Results: The few experimental data available on basic physical processes are reproduced by their beam model. The experimental verification of absorbed dose distributions in extended target volumes yields an overall agreement, with a slight underestimation of the lateral spread. Cell survival along a 4 cm extended target is reproduced with remarkable accuracy.Conclusions: The authors presented a simple simulation model for therapeutical He-4 beams which they introduced in TRiP98, and which is validated experimentally by means of physical and biological dosimetries. Thus, it is now possible to perform detailed treatment planning studies with He-4 beams, either exclusively or in combination with other ion modalities. (C) 2016 Author(s).