Triple-energy high-count-rate x-ray computed tomography scanner using a cooled cadmium-telluride detector

Abstract

To obtain three kinds of tomograms at three different X-ray energy ranges simultaneously, we have constructed a triple-energy (TE) X-ray photon counter with a cooled cadmium telluride (CdTe) detector and three sets of comparators and microcomputers. X-ray photons are detected using the CdTe detector, and the event pulses produced using amplifiers 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. We performed TE computed tomography (TE-CT) at a tube voltage of 100 kV. Using four lead pinholes, three tomograms were obtained simultaneously. Iodine-K-edge CT was carried out utilizing an energy range of 33-50 keV. At a tube voltage of 100 kV and a current of 0.11 mA, the count rate was 21 kilocounts per second (kcps).