Effect of tumor blood flow manipulations on radiation response

The effect of anesthestics and several vasoactive agents on the blood flow, temperature, and radiation response of the solid murine KHT sarcoma was evaluated to better understand the relationship of tumor blood flow and the proportion of hypoxic cells. Tumor blood flow, assessed by 133-Xenon clearance, decreased by 59 and 24% following treatment with pentobarbital and urethane, respectively. In addition, both drugs reduced body and tumor temperature. Metaraminol, a sympathomimetic agent, and nitroglycerin also reduced tumor blood flow by 40 and 12%, respectively. Tumor irradiation response following drug treatment was quantitated by an in vitro agar assay. Results indicate that drug-induced reductions in tumor blood flow generally result in an increase in the apparent tumor cell hypoxic fraction.