ANTHROPOMORPHIC FILM PHANTOM FOR THREE-DIMENSIONAL STEREOTACTIC RADIOSURGICAL DOSIMETRY

摘要

A method and system for recording and verifying three-dimensional dose distributions administered during stereotactic radiosurgery using an anthropomorphic film phantom are provided. The method provides a phantom (11) including a head-shaped hollow shell (12), which mounts a cassettebox therein (14), which in turn may contain a simulated lesion (16) similar to the lesion to be treated. An image is taken of the head-shaped shell including the cassettebox and the simulated lesion using, for example, a CT or MRI scanner. The image is used to develop a stereotactic radiosurgery plan, which includes creating an intended three-dimensional dose distribution map to 'treat' the simulated lesion. Thereafter, the simulated lesion is removed from the cassettebox and the cassettebox is loaded with multiple layers of film (42) separated by spacers (44) having tissue-equivalent characteristics. Then, the three-dimensional radiation dose described by the stereotactic radiosurgery plan is delivered to the head-shaped shell including the cassettebox loaded with the film. Next, the multiple layers of film are removed from the cassettebox, and multiple dose images are obtained based on the film. Thereafter, based on the multiple dose images, a measured three-dimensional dose distribution map is obtained. The measured three-dimensional dose distribution map is coregistered in software with the intended three-dimensional dose distribution map that was previously developed, to ascertain any discrepancies therebetween to determine inaccuracies included in the original stereotactic radiosurgery plan.