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Abstract #4202

Single-Dose X-Ray Irradiation Changes Significantly Tumor Perfusion, as Measured by In Vivo DCE 1H MRI

HyungJoon Cho1, Ellen Ackerstaff1, Matthew Kaag2, Mihai Coman1, Jason A. Koutcher1

1Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 2Dept. of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA

Applying a priming dose of radiation to radioresistant, hypoxic tumors may be associated with reoxygenation of previously hypoxic areas and increased tumor radiosensitivity. Here, we assess in the radioresistant MCa tumor the effects of single high-dose irradiation on tumor perfusion as a function of time after irradiation. Single high-dose X-ray irradiation reduced tumor perfusion in the short term whereas 24h postirradiation tumor perfusion increased which may be indicative of reoxygenation. DCE MRI may be a valuable tool to evaluate the window of increased radiation sensitivity after priming radioresistant tumors with a single high dose of radiation.