Double-Photon Emission Imaging with High-Resolution Si/CdTe Compton Cameras

Application of Compton cameras to nuclear medicine or small animal imaging is a challenging subject. A major issue is insufficient spatial resolutions of the existing Compton camera systems. We developed an imaging system consisting of two Si/CdTe Compton cameras, which allows us to investigate γ- γ coincidence imaging for a variety of radioisotopes, including 111 In, which emits double photons of 171 and 245 keV per decay and has been used for a long time in nuclear medicine and many commercialized radiotracers. We demonstrated with it a drastic reduction of a tail of the point spread function, compared with that of the traditional method, and obtained a spatial resolution of 4.5 mm full-width at half-maximum (FWHM) at 41.35 mm.