The specific aims of the proposed research are: (1) To optimize the detectors with respect to their active volume to achieve the highest possible sensitivity with good spatial resolution. (2) To improve and expand the electronic detection circuit to accommodate signals from over 200 solid-state detectors. (3) To develop data acquisition and image processing software that allows the formation of a high quality image over the entire portal field. (4) To develop a method of comparing portal images to the simulation radiographs taken prior to accelerator treatment and to detect patient motion during treatment. (5) To build a fully functional, field prototype and test it with phantoms at the Radiation Oncology Department at the Massachusetts General Hospital.
