Performance evaluation of a clinical SPECT system with multifocal collimator for brain studies

BACKGROUND: Single-photon emission computed tomography (SPECT) is an indispensable examination for evaluating brain function to diagnose dementia. During head examination, the collimator makes contact with the shoulders, which often causes the patient discomfort. A new multifocal high-resolution collimator (SMARTZOOM high resolution and extended [SZHRX]) can maintain image quality, even when there is distance between the patient and the collimator. Therefore, it may be a useful tool to prevent patient discomfort during head imaging. PURPOSE: In this study, we evaluated spatial resolution, sensitivity, uniformity, and %contrast in several basic experiments using different phantoms to clarify the image quality of the multifocal collimator. METHODS: I nuclides, which were sealed in several phantoms and imaged using SZHRX. The rotation radius for SZHRX was varied from 24-34.5 cm. For comparison, low-energy high-resolution (LEHR) and low-medium energy general purpose (LMEGP) images were acquired with a rotation radius of 14 cm. Spatial resolution, sensitivity, uniformity, and %contrast were calculated from the images obtained using each phantom and collimator. RESULTS: I, the %contrast of SZHRX and LMEGP were comparable. CONCLUSIONS: It is possible to acquire images with high spatial resolution and uniformity, even if the rotation radius is widened by the use of SZHRX. The image quality of SZHRX obtained in this study will be helpful for future clinical applications.