The use of CdTe or CdZnTe for pulse-counting and current-mode medical imaging applications

Recent progress in CdTe and CdZnTe detector research has made these detectors appear attractive for medical imaging. As part of a feasibility study, Monte Carlo simulations have been developed to investigate the detection efficiency and scatter rejection capabilities of these materials at diagnostic energies. We have also analyzed the count rate limitations and current mode capabilities of Cd(Zn)Te. This preliminary work indicates that the 3–4 keV FWHM energy resolution and the 105 cps/channel of which these detectors are capable should be adequate for most applications. In addition, although further experimental measurements are needed, we expect that the current mode operation of these detectors is acceptable for many systems. The major drawback of Cd(Zn)Te detectors is the low photopeak efficiency at 140 keV. In order to improve this efficiency, we have examined both a novel singular-value-decomposition (SVD) algorithm and a hardware-based technique to correct for spectral distortion arising from charge trapping.