Differences in the performance of cadmium-zinc-telluride (CZT) cameras or collimation systems that have recently been commercialized for myocardial SPECT remain unclear. In the present study, the performance of 3 of these systems was compared by a comprehensive analysis of phantom and human SPECT images. Methods: We evaluated the Discovery NM 530c and DSPECT CZT cameras, as well as the Symbia Anger camera equipped with an astigmatic (IQÁSPECT) or parallel-hole (conventional SPECT) collimator. Physical performance was compared on reconstructed SPECT images from a phantom and from comparable groups of healthy subjects. Results: Classifications were as follows, in order of performance. For count sensitivity on cardiac phantom images (countsÁs 21 ÁMBq 21 ), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQÁSPECT, 390; and conventional SPECT, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in countsÁs 21 ÁMBq 21 : 11.4 6 2.6, 5.6 6 1.4, 2.7 6 0.7, and 0.6 6 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQÁSPECT, 15.0 mm; and conventional SPECT, 15.3 mm, also in accordance with the analysis of the sharpness of myocardial contours on human images (in cm 21 : 1.02 6 0.17, 0.92 6 0.11, 0.64 6 0.12, and 0.65 6 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQÁSPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 6 1.0, 4.5 6 0.5, 3.9 6 0.6, and 3.4 6 0.3, respectively). Conclusion: The performance of CZT cameras is dramatically higher than that of Anger cameras, even for human SPECT images. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c, whereas count sensitivity is markedly higher with the DSPECT.Key Words: CZT-cameras; high-speed SPECT; myocardial perfusion imaging; count sensitivity St ress myocardial SPECT has been markedly enhanced by the recent commercialization of cameras with semiconductor (cadmium-zinc-telluride [CZT]) detectors or new collimation systems. These improved systems enhance the sensitivity of count detection and thereby enable recording times or tracer doses to be reduced, a property that has highly favorable consequences on patient comfort and radiation exposure (1-4). This enhancement is based mainly on acquisitions that are heart-centric but obtained with very different technologies: first, for the IQÁSPECT system (Siemens Medical Solutions (5-8)), an Anger camera equipped with collimators convergent on the image center (astigmatic collimators); second, for the DSPECT system (Spectrum Dynamics (9-13)), mobile columns of CZT detectors with wide parallel-hole collimators; and third, for the Discovery NM 530c system (GE Healthcare (14-21)), fixed CZT detectors with multipinhole collimators.The respective performance of these new cameras and collimation systems has been analyzed, but ...