Radiosensitization of the rats' rhabdomyosarcoma R 1 by chloronitroimidazole compound--P40 dependent on radiation dose in fractionated radiotherapy.

The radiosensitizing effectiveness of 1-(2-hydroxy-3-methoxy-propyl)-2-chloro-4-nitroimidazole (P40) dependent on various fractionated schedules was tested in the rat solid tumor, rhabdomyosarcoma R 1. P40 combined conventional fractionation of gamma rays exerted no radiosensitizing effect measured as local control and growth delay as well. In contrary, the significant sensitization has been noticed when nontoxic doses of the nitroimidazole were combined with higher (3.7 Gy) doses of radiation. Low toxicity of P40 is encouraging for further experimental studies.