X-ray imaging sensor using CdTe crystals for dual energy X-rayabsorptiometry

The authors have designed and built a multi-channel cadmium telluride detector array to test its suitability as an X-ray imaging sensor for dual energy X-ray absorptiometry. The X-ray imaging sensor was constructed of 64 CdTe detector elements with high frequency current amplifiers, discriminators, and counters. The detector elements were operated in the photon counting mode and output pulses induced by the X-ray photons were separated into two energy levels according to their height. The energy resolution of the detector elements was 18.7% to 59.54 keV gamma-rays. In combination with a K-edge filter to produce dual energy X-rays, the X-ray imaging sensor was able to generate two energy X-ray images simultaneously over a short time. By applying a simple energy subtraction method to these images, bone phantoms were distinguished from the overlying tissue phantoms and their densities could be successfully measured. It was clearly demonstrated that this X-ray imaging sensor using CdTe crystals has good potential for high speed bone densitometry