Detectability in SPECT Myocardial Perfusion Imaging: Comparison between a Conventional and a Semiconductor Detector System

摘要

The aim of this study is to compare cold lesions detectability in myocardial perfusion SPECT images acquired by two cameras: a conventional SPECT with scintillation detector (Philips Cardio MD) and a cadmium-zinc-telluride (CZT) semiconductor detector system(GE Discovery NM 530C). The test object was an anthropomorphic torso phantom with cardiac insert, filled with ~(99m)Tc, simulating a SPECT myocardial perfusion acquisition. Images were reconstructed using the standard clinical department protocol, and analyzed by axial and lateral count profiles, and polar distributions. The lateral profile showed that the contrast between the lesion region and background in the Cardio MD camera is higher (62.2%) than in the CZT camera (42.5%). The axial profile showed a higher contrast (37.0%) in the CZT camera compared to the Cardio MD (31.9%). CZT showed a higher contrast between background and the maximum activity point along the line (68.2%) than in the Cardio MD (57.5%). Performing the maximum relative count region and the lesion area analysis, it was verified that the contrast between these regions are 31.2% and 25.5% to CZT and Cardio MD, respectively. The polar map in the CZT camera displays a better uniformity between the segments' counting, which means the lesion identification is clearer than in the Cardio MD camera, where the distribution is diffuse and the lesion is unclear. The results showed that the cold myocardium lesion detectability is enhanced in the CZT camera. In conclusion, the physical performance of CZT camera is higher than conventional camera, but further studies are required to evaluate other parameters such as the influence of positioning and attenuation.