Effective particle energies for stopping power calculation in radiotherapy treatment planning with protons and helium, carbon, and oxygen ions
Effective particle energies for stopping power calculation in radiotherapy treatment planning with protons and helium, carbon, and oxygen ions
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DOI：
10.1088/0031-9155/61/20/n542
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发表时间：
2016-10-21
影响因子：
3.5
通讯作者：
Kanematsu, N.
中科院分区：
文献类型：
--
作者：
Inaniwa, T.;Kanematsu, N.
人体组织相对于水的阻止本领比（SPR）取决于粒子的能量。然而，为了简单起见，大多数分析剂量计划系统不考虑SPR随粒子能量沿着射束路径的变化，而是假设SPR估计的恒定能量。由于这种简化的范围误差可能是必不可少的，这取决于粒子种类和假设的能量。通过在SPR估计中假设被称为“有效能量”的合适能量，可以使该误差最小化。然而，迄今为止，从未研究过实际患者几何形状的有效能量。我们研究了质子，氦，碳，氧离子放射治疗的有效能量，使用体积模型的参考男性和女性phanomaly提供的国际辐射防护委员会（ICRP）。通过比较考虑和不考虑粒子能量变化时计算的粒子射程，估计了射程误差。质子、氦、碳和氧离子的有效能量分别为70 MeV、70 MeV、131 MeV和156 MeV。利用确定的有效能量，距离误差减小到。0.3 mm用于各个颗粒种类。对于多粒子种类的SPR估计，推荐100 MeV的有效能量，其距离误差为
The stopping power ratio (SPR) of body tissues relative to water depends on the particle energy. For simplicity, however, most analytical dose planning systems do not account for SPR variation with particle energy along the beam's path, but rather assume a constant energy for SPR estimation. The range error due to this simplification could be indispensable depending on the particle species and the assumed energy. This error can be minimized by assuming a suitable energy referred to as an 'effective energy' in SPR estimation. To date, however, the effective energy has never been investigated for realistic patient geometries. We investigated the effective energies for proton, helium-, carbon-, and oxygen-ion radiotherapy using volumetric models of the reference male and female phantoms provided by the International Commission on Radiological Protection (ICRP). The range errors were estimated by comparing the particle ranges calculated when particle energy variations were and were not considered. The effective energies per nucleon for protons and helium, carbon, and oxygen ions were 70 MeV, 70 MeV, 131 MeV, and 156 MeV, respectively. Using the determined effective energies, the range errors were reduced to. 0.3 mm for respective particle species. For SPR estimation of multiple particle species, an effective energy of 100 MeV is recommended, with which the range error is