A comparison between the performance of a pixellated CdZnTe based gamma camera and Anger NaI(TI) scintillator gamma camera

The commonly use Anger camera provides a relatively simple, large-scale solution to nuclear medicine imaging. However it has some disadvantages: count-rate limitation, nonlinear spatial resolution and relatively poor energy contrast. Many efforts have been invested over the past few years aiming at replacing the current Anger technology with various new technologies. One of the most promising technology currently under investigation is based on room temperature solid-state CdZnTe (CZT). The pixellated structure of a CZT camera naturally provides an improved count rate capability and intrinsic spatial resolution. The direct conversion of gamma photon to charge-carriers, provides an improved energy resolution thus may lead to better scattering events rejection and a better image contrast. A major limitation of the CZT technology is the lower sensitivity due to limitation in fabrication of thick crystals and incomplete charge collection. An additional reduction in sensitivity is due to charge carrier share between neighboring pixels. Several small area planar CZT camera were built and tested over the years, but the expected advantages of the CZT technology over the current NaI technology has not been realized yet. The present work compares between the performances of the NaI(Tl) Anger camera and a CZT camera