Computed tomography with a linear accelerator with radiotherapy applications

An earlier paper [Simpson et al., Med. Phys. 9, 574 (1982)] described a computed tomography (CT) scanner that was constructed by adding a detector array to a 4-MV isocentric linear accelerator. Since the previous article, the detector array has been improved and we now demonstrate better than 3-mm spatial resolution and better than 1% relative electron density discrimination. A series of pictures from volunteer patients is included. Normal anatomy is visualized with bone, muscle, fat, and air being clearly delineated.