Monte Carlo dosimetry of a cell culture irradiation model using a 6 MV X-ray beam

We describe a cell culture irradiation model based on the use of a 6 MV linear accelerator. The determination of dose delivered to the cell culture relied upon a carefully validated Monte Carlo simulation of the linear accelerator head, followed by radiation transport calculations of relative dose on a model of the clonogenic assay, which included the cell culture flask and supporting media. Absolute dose was determined by cross calibration of the Monte Carlo model with ionization chamber measurements along the central axis of a water phantom. An experimental setup based on the irradiation model was used to obtain survival curves of a human cell line of glioblastoma multiforme (U-373 MG). Our measurements show excellent agreement with data previously reported in the literature.