Kempe Johanna, Brahme Anders
Division of Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University, Box 260, SE-171 76 Stockholm, Sweden.
Med Phys. 2008 Jan;35(1):159-70. doi: 10.1118/1.2815935.
Analytical expressions for the mean energy and range of therapeutic light ion beams and low- and high-energy electrons have been derived, based on the energy dependence of their respective stopping powers. The new mean energy and range relations are power-law expressions relevant for light ion radiation therapy, and are based on measured practical ranges or known tabulated stopping powers and ranges for the relevant incident particle energies. A practical extrapolated range, Rp, for light ions was defined, similar to that of electrons, which is very closely related to the extrapolated range of the primary ions. A universal energy-range relation for light ions and electrons that is valid for all material mixtures and compounds has been developed. The new relation can be expressed in terms of the range for protons and alpha particles, and is found to agree closely with experimental data in low atomic number media and when the difference in the mean ionization energy is low. The variation of the mean energy with depth and the new energy-range relation are useful for accurate stopping power and mass scattering power calculations, as well as for general particle transport and dosimetry applications.
基于治疗用轻离子束以及低能和高能电子各自的阻止本领对能量的依赖性，已经推导出了它们的平均能量和射程的解析表达式。新的平均能量和射程关系是与轻离子放射治疗相关的幂律表达式，并且是基于对相关入射粒子能量的实测实际射程或已知的表格化阻止本领和射程得出的。定义了轻离子的实际外推射程(Rp)，类似于电子的外推射程，它与初级离子的外推射程密切相关。已经开发出一种对所有材料混合物和化合物都有效的轻离子和电子的通用能量 - 射程关系。新关系可以用质子和α粒子的射程来表示，并且发现在低原子序数介质中以及平均电离能差异较小时与实验数据非常吻合。平均能量随深度的变化以及新的能量 - 射程关系对于精确的阻止本领和质量散射本领计算以及一般的粒子输运和剂量学应用都很有用。
