Impact of a novel respiratory motion reduction block for myocardial perfusion SPECT image quality: a phantom study

Patient motion, particularly due to respiration, often introduces image distortions that compromise diagnostic accuracy in myocardial perfusion single-photon emission computed tomography (SPECT). To address this issue, we developed a novel respiratory motion reduction block (RRB) designed to minimize the respiratory motion of the heart. This study aims to evaluate the impact of the cardiac-centered with RRB (CC_RRB) orbit, achieved using the RRB, on myocardial perfusion SPECT image quality. SPECT acquisition of a cardiac phantom was performed at the circular, neighboring elliptical (NE), and CC_RRB orbits. The CC_RRB orbit was achieved with RRB placed in front of the phantom based on the NE orbit. Count profile curves of the lesion and uniform slice images were obtained from the circumferential profile. Lesion contrast, normal accumulation uniformity, and count distortion were calculated from the circumferential profiles. Full width at half maximum (FWHM) was measured in the lateral, anterior, septal, and inferior walls of the myocardium, and both the mean and standard deviation (SD) were calculated. The lesion contrast was the highest in the NE orbit, slightly lower in the CC_RRB orbit, and remarkably lower in the circular orbit than in the NE orbit. The uniformity and count distortion were superior for the CC_RRB orbits. The SD of FWHM was greater in the circular and NE orbits. The CC_RRB orbit effectively improves uniformity in SPECT imaging, preserving lesion contrast and spatial resolution. The CC_RRB orbit provides a practical, accessible approach for enhancing image quality in clinical settings.