Oxygen-carrying Perfluorochemical Emulsion As an Adjuvant to Radiation Therapy in Mice

The potential of an oxygen-carrying perfluorochemical emulsion (PFCE) to enhance radiation damage in Lewis lung tumor growing in C57BL/6J X DBA/2J F1 mice was examined. PFCE and 95% O2:5% CO2 (carbogen) breathing caused a significant enhancement of single-fraction radiation damage measured by the growth delay assay. The dose-response effect of PFCE was very broad; doses as small as 0.5 ml/mouse were effective, and doses of 0.3 to 0.4 ml/mouse gave maximal enhancement. The peak dose-modifying factor was 2.8 +/- 0.6 (S.E.). The addition of 0.3 ml of perfluorochemical-free annex solution with carbogen breathing produced a smaller enhancement in tumor growth delay; the dose-modifying factor was 1.5 +/- 0.2. When the perfluorochemical treatment was added to a fractionated course of radiation therapy, a dose-modifying effect of 1.8 +/- 0.3 was obtained. Oxygen-carrying PFCE may provide a nontoxic, clinically useful method of increasing the effectiveness of radiation therapy and of certain chemotherapeutic agents.