title: Misonidazole enhancement of radiation-induced growth delay in rat rhabdomyosarcoma tumours exposed to accelerated carbon and neon ions.
abstract: The response of a rat rhabdomyosarcoma tumour was assessed by measurements of radiation-induced growth delay resulting from administration of the hypoxic cell sensitizer misonidazole in combination with single and fractionated doses of X-rays and charged-particle radiation. Enhancement ratios of 1.8--2.1 were obtained following single doses of misonidazole (500 mg/kg i.p.) and 225 kV X-rays. Single doses of misonidazole with either carbon-ion or neon-ion radiation in the 4 cm extended-peak ionization region led to enhancement ratios of 1.2--1.3. When combined misonidazole (300 mg/kg i.p.) and X-ray treatments were given in four daily fractions, the enhancement ratios decreased to 1.2--1.5. However, a four-fraction schedule using either carbon-ion or neon-ion radiation in combination with misonidazole gave enhancement ratios of 1.1--1.3, which are similar to the values obtained for single-dose schedules with the sensitizer and charged-particle radiation.
mesh_terms: D000818:Animals; D002244:Carbon; D002470:Cell Survival; D004307:Dose-Response Relationship, Radiation; D004735:Energy Transfer; D008920:Misonidazole / Q000494:pharmacology*; D009356:Neon; D009593:Nitroimidazoles / Q000494:pharmacology*; D010315:Particle Accelerators; D011838:Radiation-Sensitizing Agents; D051381:Rats; D012208:Rhabdomyosarcoma / Q000532:radiotherapy*; D012513:Sarcoma, Experimental / Q000532:radiotherapy
chemical_list: D009593:Nitroimidazoles; D011838:Radiation-Sensitizing Agents; D009356:Neon; D002244:Carbon; D008920:Misonidazole