In vitro investigation of the dose-rate effect on the biological effectiveness of megavoltage X-ray radiation doses

Radiation therapy is rapidly evolving toward the delivery of higher dose rates to improve cancer treatment. In vitro experiments were performed to investigate the response of 9L and MCF-7 cancer cell lines, exposed to 10 MV X-ray radiations. Up to 8 Gy was delivered at a dose-rate of 50 cGy/min compared to 5 Gy/min. The data obtained emphasizes the importance of taking into account not only the physical, but also the radiobiological parameters, when planning a particular cancer treatment.