X-ray energy separation method using a CdTe semiconductor X-ray imaging sensor and photon counting method

A multichannel X-ray imaging sensor using a CdTe compound semiconductor radiation detector in photon counting mode was developed and tested for digital X-ray imaging and an X-ray energy separation capability. The X-ray imaging sensor was constructed of CdTe detector elements at a pitch of 0.25 mm. High band amplifiers, discriminators, and counters attached to each element formed the pulse counting circuit. Charge pulses generated by absorbed X-ray photons were directly counted and separated into two energy regions. Digitized X-ray images containing energy information were thus obtained. Using this sensor two separate X-ray images of different energy can be obtained simultaneously. A 256-channel X-ray imaging sensor was prepared and used to provide spatial resolution measurement for an X-ray charge. Low and high energy images of a hand phantom were thus obtained and both a soft tissue image and a bone image were produced using an energy subtraction method