Characterization and Evaluation of the Response of Rat 9L Subcutaneous Tumors to Heat or X Rays

摘要

The response of a tumor to heat and x irradiation was studied using the rat 9L subcutaneous (sc) tumor model. The relationship of cell survival to tumor cure after hyperthermic treatment is described. Cell survival followed a simple exponential function with a decreasing slope as temperature increased. Except for a small highly sensitive subpopulation, cells from large tumors had the same sensitivity at 44 exp 0 C as those from small tumors. The radiosensitivity of 9L tumor cells, measured with the colony-forming assay, did not vary with changes in tumor weight, appearance of necrosis, or the use of anesthesia. However, the composite survival curve showed a sensitivity intermediate between and statistically different from that observed either for exponential cells from monolayer cultures, single cells from dissociated tumors, or tumor cells from N sub 2 -asphyxiated rats. Although cellular recovery and perfusion-limited hypoxia are major contributors to the observed radiosensitivity, neither of these factors is probably the sole cause. (ERA citation 05:027852)