A prototype fan-beam optical CT scanner for polymer gel dosimetry

A prototype optical CT scanner has been developed for scanning polymer gel dosimeters used in 3D radiation therapy dose verification. The scanner is based on a 3rd generation, fan-beam CT design and employs a 543 nm laser fanned through a 60 deg. line-generating lens. A series of 5 detector arrays or 64 elements each collects light on the distal side of the water tank. Pre-detector collimators are employed to reject light scattered away from incident ray trajectory. Results of scanner characterisation studies, as well as preliminary data acquired on irradiated polymer gels, are discussed.