Kinetics of post irradiated transplantable tumor

The effect of ionizing radiation in three tumor systems was studied. Experimental animal tumors were third generation isoplants of a mammary carcinoma which arose spontaneously in a C3H/He mouse and a fibrosarcoma which was induced by Methylcolantrane. Other system was a human epidermoid carcinoma which arose in a oral cavity. Single cell suspension was prepared and transplanted into mouse thigh intraculaneously. Single dose and two fractionated dose irradiation was carried out with 180 kVp x-ray when tumors reached approximately 1 cm in average diameter. The reoxygenation kinetics of the third generation C3H/He mouse mammary carcinoma and the third generation Methyl-colantrane induced fibrosarcoma have been studied. And related to the time for 50% of irradiated tumors to regrow to the initial volume at irradiation (TRT 50) and to changes in tumor cell numbers. 1) Fluctuation in TRT 50 values following two dose irradiation under aerobic conditions are due to reoxygenation. 2) In C3H/He mouse mammary carcinoma, the TRT 50 value was minimal for a 48 hours fractionation interval. 3) In fibrosarcoma TRT 50 value was not so changeable, so the relationship of reoxygenation was a little. 4) In nude mouse which transplanted human epidermoid carcinoma was studied with tumor volume and cell number. (author)