PDF(Pubmed)
Abstract：
UNASSIGNED: The effort to translate clinical findings across institutions employing different relative biological effectiveness (RBE) models of ion radiotherapy has rapidly grown in recent years. Nevertheless, even for a chosen RBE model, different implementations exist. These approaches might consider or disregard the dose-dependence of the RBE and the radial variation of the radiation quality around the beam axis. This study investigated the theoretical impact of disregarding these effects during the RBE calculations.
UNASSIGNED: Microdosimetric simulations were carried out using the Monte Carlo code PHITS along the spread out Bragg peaks of 1H, 4He, 12C, 16O, and 20Ne ions in a water phantom. The RBE was computed using different implementations of the Mayo Clinic Florida microdosimetric kinetic model (MCF MKM) and the modified MKM, considering or not the radial variation of the radiation quality in the penumbra of the ion beams and the dose-dependence of the RBE.
UNASSIGNED: For an OAR located 5 mm laterally from the target volume, disregarding the radial variation of the radiation quality or the dose-dependence of the RBE could result in an overestimation of the RBE-weighted dose up to a factor of ∼ 3.5 or ∼ 1.7, respectively.
UNASSIGNED: The RBE-weighted dose to OARs close to the tumor volume was substantially impacted by the approach employed for the RBE calculations, even when using the same RBE model and cell line. Therefore, care should be taken in considering these differences while translating clinical findings between institutions with dissimilar approaches.
UNASSIGNED: Microdosimetric simulations were carried out using the Monte Carlo code PHITS along the spread out Bragg peaks of 1H, 4He, 12C, 16O, and 20Ne ions in a water phantom. The RBE was computed using different implementations of the Mayo Clinic Florida microdosimetric kinetic model (MCF MKM) and the modified MKM, considering or not the radial variation of the radiation quality in the penumbra of the ion beams and the dose-dependence of the RBE.
UNASSIGNED: For an OAR located 5 mm laterally from the target volume, disregarding the radial variation of the radiation quality or the dose-dependence of the RBE could result in an overestimation of the RBE-weighted dose up to a factor of ∼ 3.5 or ∼ 1.7, respectively.
UNASSIGNED: The RBE-weighted dose to OARs close to the tumor volume was substantially impacted by the approach employed for the RBE calculations, even when using the same RBE model and cell line. Therefore, care should be taken in considering these differences while translating clinical findings between institutions with dissimilar approaches.
摘要：
■近年来，在采用离子放射治疗的不同相对生物有效性（RBE）模型的机构中翻译临床发现的努力迅速增长。然而，即使对于选择的RBE模型，存在不同的实现。这些方法可以考虑或忽略RBE的剂量依赖性和围绕射束轴的辐射质量的径向变化。这项研究调查了在RBE计算过程中忽略这些影响的理论影响。
■使用蒙特卡洛代码PHITS沿1H的扩展布拉格峰进行微剂量模拟，4他，12C,16O,和水幻影中的20Ne离子。RBE是使用梅奥诊所佛罗里达微剂量动力学模型（MCFMKM）和修改后的MKM的不同实现方式计算的，考虑或不考虑离子束半影中辐射质量的径向变化以及RBE的剂量依赖性。
■对于距离目标体积5毫米的OAR，忽略辐射质量的径向变化或RBE的剂量依赖性可能会导致RBE加权剂量的高估，最高可达3.5或1.7。
■接近肿瘤体积的OAR的RBE加权剂量受到RBE计算方法的实质性影响，即使使用相同的RBE模型和细胞系。因此,在使用不同方法的机构之间翻译临床发现时，应注意考虑这些差异。
■使用蒙特卡洛代码PHITS沿1H的扩展布拉格峰进行微剂量模拟，4他，12C,16O,和水幻影中的20Ne离子。RBE是使用梅奥诊所佛罗里达微剂量动力学模型（MCFMKM）和修改后的MKM的不同实现方式计算的，考虑或不考虑离子束半影中辐射质量的径向变化以及RBE的剂量依赖性。
■对于距离目标体积5毫米的OAR，忽略辐射质量的径向变化或RBE的剂量依赖性可能会导致RBE加权剂量的高估，最高可达3.5或1.7。
■接近肿瘤体积的OAR的RBE加权剂量受到RBE计算方法的实质性影响，即使使用相同的RBE模型和细胞系。因此,在使用不同方法的机构之间翻译临床发现时，应注意考虑这些差异。
