[Radiosensitization of Lewis lung tumor by perfluorochemical emulsion comparison between single and fractionated irradiation].

Previously perfluorochemical emulsion (FDAS) was shown to enhance tumor growth delay, when applied together with breathing carbogen (95% O2+5% CO2) before and during irradiation. In the present paper, radiosensitizing effects of FDAS in tumor bearing mice were examined on a single (10 Gy) and fractionated irradiation (4 Gy, 4 times) and on the dose of administration. The results were as follows; 1) All groups of single irradiation with injection of FDAS 10-40 ml/kg could enhance the radiosensitivity of LLC bearing mice. 2) Tumor growth of even fractionated irradiation groups was significantly delayed by administration of FDAS more than 5 ml/kg. 3) In case of fractionated irradiation, the minimum effective dose of FDAS was estimated to be 5 ml/kg per irradiation, which coincided with that of single irradiation. It was concluded that FDAS in fractionated irradiation could increase the radiosensitivity in tumor bearing mice with more than 5 ml/kg injection. Therefore, FDAS may be useful as a radiosensitizer for clinical application in fractionated radiation therapy. Furthermore, since irradiation doses of single (10 Gy) and even fractionated irradiation (4 Gy X 4 times) were approximately iso effective dose, it may be considered that administration of more than 5 ml/kg (minimum effective dose) FDAS at each irradiation gave similar radiosensitizing effects to both single and fractionated irradiation.