一引言在当今的放射医疗中,通常使用~(60)Co源放出的γ射线(目前在国外,使用电子、质子或快中子进行放射治疗的临床与实验研究也已迅速开展)。由于γ射线不仅能够破坏病变区细胞的生理机能,同时也可能破坏正常组织的生理机能,因此应当尽量提高γ射线在病变区的吸收率,同时很自然地要尽量避免在健康区吸收,即努力提高放射治疗效率将是一个不容忽视的问题。 I. INTRODUCTION In today’s radiation medicine, gamma rays emitted from ~(60)Co sources are usually used (currently abroad, clinical and experimental studies using electrons, protons, or fast neutrons for radiation therapy have also been rapidly carried out). Since γ-rays not only damage the physiological function of cells in the affected area, but also may destroy the physiological function of normal tissues, they should try to increase the absorption rate of γ-rays in the lesion area. Naturally, it is necessary to avoid absorption in healthy areas as much as possible. Raising the efficiency of radiation therapy will be a problem that cannot be ignored.