Use of a perfluorochemical emulsion to improve the radiation response of BA1112 rat sarcomas

The perfluorochemical emulsion, Fluosol-DA, is being tested in this laboratory as an adjunct to radiation therapy. The authors postulated that the exceptional O/sub 2/-carrying capacity of the perfluorochemicals and the small size of the micelles might permit oxygenation of the normally hypoxic areas of solid tumors. The authors tested the ability of this agent to improve the oxygenation and thus the radiation response of BA1112 rat sarcomas. Tumor-bearing rats were injected with Fluosol and gassed with carbogen (95% O/sub 2//5% CO/sub 2/) for 15 min prior to and during irradiation. Following treatment, the tumors were excised and the cells were suspended and assayed for survival by colony formation in vitro. Fluosol + carbogen significantly increased the radiation cytotoxicity. Although carbogen alone also increased the radiation response, this effect was significantly less than that with Fluosol + carbogen in combination. Unoxygenated Fluosol had no effect on tumor radiosensitivity. Complete radiation dose-response curves indicated that treatment with Fluosol + carbogen reduced the number of hypoxic tumor cells but did not alter the D/sub 0/ of the survival curve. Preliminary results of tumor control experiments suggest that pretreatment with Fluosol + carbogen also lowers the TCD/sub 50/