The specific advantages of ion beams for application in tumor therapy are attributed to their different macroscopic and microscopic energy deposition pattern as compared to conventional photon radiation. On the macroscopic scale, the dose profile with a Bragg peak at the highest depths and small lateral scattering allow a better conformation of the dose to the tumor. On the microscopic scale, the localized energy deposition around the trajectory of the particles leads to an enhanced biological effectiveness, typically expressed in terms of clinically significant relative biological effectiveness (RBE). Experimental investigations reveal complex dependencies of RBE on many physical and biological parameters, as e.g. ion species, dose, position in the field, and cell or tissue type. In order to complement the experimental work, different approaches are used for the characterization of the specific physical and biological properties of ion beams. In a set of two papers, which are linked by activities within a European HORIZON 2020 project about nuclear science and application (ENSAR2), we describe recent developments in two fields playing a key role in characterizing the increased biological effectiveness. These comprise the biophysical modeling of RBE and the microdosimetric measurements in complex radiation fields. This second paper focuses on microdosimeters and on the importance of providing the instrumental measurement of the spectra of the imparted energy. The relevance of microdosimetric quantities, complementary to the absorbed dose is emphasized. This parts provides an overview of the microdosimetric concepts and the recent experimental developments in the field of microdosimetry applied to ion beam therapy. Finally, a non-exhaustive, dedicated section in included to emphasize the relevance of Monte Carlo simulations as tool for the design of the microdosimetric detectors and for the interpretation of the experimental results. For the two distinctive clinical beams of protons and carbon ions, the lineal-energy parameters are correlated to the clinical concept of Linear Energy Transfer (LET) and RBE. The possibilities of applying experimental microdosimetry in ion-beam therapy are discussed considering the consolidated irradiation characteristics as well as the most recent developments.

与传统的光子辐射相比，离子束在肿瘤治疗中的特殊优势归因于其不同的宏观和微观能量沉积模式。在宏观尺度上，在最高深度处具有布拉格峰的剂量分布和较小的横向散射允许剂量更好地符合肿瘤。在微观尺度上，围绕颗粒轨迹的局部能量沉积导致增强的生物学有效性，通常以临床上显着的相对生物学有效性（RBE）表示。实验研究揭示了RBE对许多物理和生物学参数的复杂依赖性，例如离子种类，剂量，在野外的位置以及细胞或组织的类型。为了补充实验工作，使用不同的方法来表征离子束的特定物理和生物学特性。在一套由欧洲HORIZON 2020项目有关核科学和应用（ENSAR2）的活动所链接的两篇论文中，我们描述了两个领域的最新进展，这些进展在表征提高的生物有效性方面起着关键作用。这些包括RBE的生物物理建模和复杂辐射场中的微剂量测量。第二篇论文重点介绍了微量剂量计，以及提供对所传递能量的光谱进行仪器测量的重要性。强调了与吸收剂量互补的微量剂量的相关性。本部分概述了微剂量学的概念以及应用于离子束治疗的微剂量学领域的最新实验进展。最后，其中包括一个非详尽的专用部分，以强调蒙特卡洛模拟作为微剂量检测器设计和实验结果解释工具的相关性。对于质子和碳离子这两种独特的临床束，线能量参数与线性能量转移（LET）和RBE的临床概念相关。考虑到合并的辐射特性以及最新发展，讨论了在离子束治疗中应用实验微剂量法的可能性。其中的专用部分强调了蒙特卡洛模拟作为微剂量检测器设计和实验结果解释工具的相关性。对于质子和碳离子这两种独特的临床束，线能量参数与线性能量转移（LET）和RBE的临床概念相关。考虑到合并的辐射特性以及最新发展，讨论了在离子束治疗中应用实验微剂量法的可能性。其中的专用部分强调了蒙特卡洛模拟作为微剂量检测器设计和实验结果解释工具的相关性。对于质子和碳离子这两种独特的临床束，线能量参数与线性能量转移（LET）和RBE的临床概念相关。考虑到合并的辐射特性以及最新发展，讨论了在离子束治疗中应用实验微剂量法的可能性。线性能量参数与线性能量转移（LET）和RBE的临床概念相关。考虑到合并的辐射特性以及最新发展，讨论了在离子束治疗中应用实验微剂量法的可能性。线性能量参数与线性能量转移（LET）和RBE的临床概念相关。考虑到合并的辐射特性以及最新发展，讨论了在离子束治疗中应用实验微剂量法的可能性。