High-speed tripe-energy x-ray photon counter using a room-temperature cadmium-telluride detector and its application to high-spatial-resolution low-dose computed tomography

We have constructed a triple-energy (TE) X-ray photon counter with a room-temperature cadmium telluride (CdTe) detector and three sets of comparators and microcomputers to obtain three kinds of tomograms at three different X-ray energy ranges simultaneously. X-ray photons are detected using the CdTe detector, and the event pulses produced using amplifier module are sent to three comparators simultaneously to regulate three threshold energies of 15, 33 and 50 keV. Using this counter, the energy ranges are 15-33, 33-50 and 50-100 keV; the maximum energy corresponds to the tube voltage. The photon-energy resolution was 3.5% at 59.5 keV. We performed TE computed tomography (TE-CT) at a tube voltage of 100 kV. Using four lead pinholes, three tomograms were obtained simultaneously. Gadolinium-K-edge CT was carried out utilizing an energy range of 50-100 keV. At a tube voltage of 100 kV and a current of 1.60 mA, the count rate was 59 kilocounts per second (kcps).