Compared Performance of High-Sensitivity Cameras Dedicated to Myocardial Perfusion SPECT: A Comprehensive Analysis of Phantom and Human Images

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 (IQ-SPECT) 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 (counts-s(-1)-MBq(-1)), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQ.SPECT, 390; and conventional SPEC, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in counts.s(-1).MBq(-1): 11.4 +/- 2.6, 5.6 +/- 1.4, 2.7 +/- 0.7, and 0.6 +/- 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQ.SPECT, 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(-1): 1.02 +/- 0.17, 0.92 +/- 0.11, 0.64 +/- 0.12, and 0.65 +/- 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQ.SPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 +/- 1.0, 4.5 +/- 0.5, 3.9 +/- 0.6, and 3.4 +/- 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.