Optimisation of the design of SOI microdosimeters for hadron therapy quality assurance
Optimisation of the design of SOI microdosimeters for hadron therapy quality assurance
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DOI：
10.1088/1361-6560/aae66b
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发表时间：
2018-11-01
影响因子：
3.5
通讯作者：
Rosenfeld, A. B.
中科院分区：
文献类型：
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作者：
Bolst, D.;Guatelli, S.;Rosenfeld, A. B.
绝缘体上硅(SOI)微剂量计操作简单，空间分辨率高，为强子治疗的常规质量保证(QA)提供了一种有前途的方法。然而，之前已经证明的一个复杂的问题是，由于辐射场的强方向性，对于临床碳离子领域的SOI器件，使用柯西公式计算的平均弦长<；L(柯西)>；是不合适的。在以前的研究中，我们证明了平均路径长度，即带电粒子在敏感体积(SV)中的平均路径，是通过微剂量学动力学模型获得微剂量量和生物学相关值，即相对生物效率(Rbe)的更合适的方法。以前的工作仅限于重离子治疗(HIT)中典型的单能C-12离子束，本文将扩展到研究原始质子束中的<；L(路径)和展开临床质子和碳离子的布拉格峰。此外，还研究了几种不同SV设计的SOI器件的角度相关性，以量化对准对L(路径)>；的影响。证明了利用质子和C-12离子束的能量沉积谱，可以沿着原始或SOBP的深度精确地估计L(路径)。通过这种观察，可以快速、准确地估计实验用的L(路径)。
Silicon-on-insulator (SOI) microdosimeters offer a promising method for routine quality assurance (QA) for hadron therapy due to their ease of operation and high spatial resolution. However, one complication which has been shown previously is that the traditional use of the mean chord length, < l(Cauchy)>, calculated using Cauchy's formula, for SOI devices in clinical carbon ion fields is not appropriate due to the strong directionality of the radiation field. In a previous study, we demonstrated that the mean path length, < l(Path)>, which is the mean path of charged particles in the sensitive volume (SV), is a more appropriate method to obtain microdosimetric quantities and biological relevant values, namely the relative biological effectiveness (RBE) by means of the microdosimetric kinetic model. The previous work, which was limited to mono-energetic C-12 ion beams typical of heavy ion therapy (HIT), is extended here to investigate the < l(Path)> in a pristine proton beam as well as for spread out Bragg peaks (SOBP) for both proton and carbon ion clinical beams. In addition, the angular dependence of the SOI device for a number of different SV designs is also investigated to quantify the effects which the alignment has on the < l(Path)>. It is demonstrated that the < l(Path)> can be accurately estimated along the depth of a pristine or SOBP using the energy deposition spectra for both proton and C-12 ion beams. This observation allows a quick and accurate estimation of the < l(Path)> for experimental use.