Relationship between RBE values of Carbon Ion and Tumor Growth Rate

抄録

Clinical trials indicate that the RBE of high LET radiation is large for slow-growing tumors. We here used 9 transplantable tumors with different growth time for each, and compared RBE values of 290 MeV/u carbon ions (74 keV/micrometer). NFSa fibrosarcoma spontaneously arisen in C3H mice and other 8 radiation-induced tumors were transplanted in hind legs, and irradiated with either Cs-137 gamma rays or 290 MeV/u carbon ions. Tumor growth delay time and specific growth delay were calculated from tumor growth time and used to obtain isoeffect doses. TG time for un-irradiated control ranged from 3 days to 9.6 days. RBE of carbon ions ranged from 2.1 to 3.4. It is concluded that tumor growth rate is less important than anticipated for a RBE determinant of carbon-ion radiation. [J Radiat Res 44:452 (2003)]