Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp camera has cadmium-zinc-telluride (CZT) detectors and direct conversion of scintillation without NaI crystal. The CZT gamma camera is also expected to improve image contrast, provide multi-isotope imaging, faster scan and short acquisition time. 9 A novel dedicated cardiac scanner, the D-SPECT (Spectrum Dynamics, Caesarea, Israel), has 9 CZT detectors (40×160 mm) with square-hole tungsten collimators. In our previous experiment, D-SPECT had 1.6-and 1.4-fold better full width at half maximum (FWHM) in both 99 m Tc and 201 Tl line-sources than the conventional anger gamma camera, respectively. Regarding photon count sensitivity, D-SPECT also had 5.03-and 6.31-fold higher photon count · s -1 · MBq -1 tress myocardial perfusion single-photon emission computed tomography (MPS) is the standard diagnostic modality in patients with known or suspected coronary artery disease (CAD). 1-4 Stress-induced myocardial ischemia and left ventricular (LV) functional parameters are markers of future cardiac events. 5-7 Moreover, recent clinical guidelines recommend ≥10% myocardial ischemia in the LV as an indication for coronary revascularization. 8 Precise diagnosis and quantification using MPS would facilitate this.Technical features of the recently developed semiconductor gamma camera include high spatial resolution, high sensitivity and high energy-spectrum resolution. This type of gamma