Planar image quality comparison between a CdZnTe prototype and a standard NaI(Tl) gamma camera

A CdZnTe prototype was evaluated along with a standard NaI(Tl) gamma camera for planar imaging performance. A 12×20 cm2 CdZnTe gamma camera comprised of 15 Imarad modules and a 3/8-in. thick NaI(Tl) gamma camera were used. A 2D brain slice phantom filled with 110 MBq of 99mTc pertechnetate was imaged at varying count densities (1 kCt–1 MCt) and distances (0–20 cm) on both camera systems. An ultra-high resolution, low-energy collimator was used for both cameras. A 15% energy window was centered on 140 keV. CdZnTe count sensitivity was 71% of NaI(Tl) in the 15% energy window. Qualitatively, the CdZnTe images have superior spatial resolution and contrast. The advantage in intrinsic resolution of CdZnTe, combined with the ultra-high resolution collimator, gives the new detector a superior line spread function which accounts for the observed image quality improvement over NaI(Tl) for this planar imaging application.