Collimator Selection for SPECT Brain Imaging: The Advantage of High Resolution

摘要: We compared a prototype long-bore (LB) high-resolution collimator with low-energy, general-purpose (LEGP) using 99mTc and 123I. The LB provided 56% improvement in tomographic resolution (autocorrelation width) over the LEGP for 99mTc; 123I, gain was 79%, providing substantially improved contrast small structures. sensitivity of collimator, however, is only 32% that LEGP. imaging tasks to be performed on [123I]IMP brain scans involve localization discrimination small, high-contrast structures detection abnormalities shape, size, or uptake, rather than simple lesions. Observer performance such higher-order known depend high spatial resolution, even at cost sensitivity. Patient studies confirmed that, resolution-limited tasks, increase outweighs increased noise due loss When degraded by smoothing LEGP, images lower factor 2.9 same time, demonstrating advantage detectors smooth reconstruction filter low-resolution without smoothing. Therefore, collimators designed substantial sensitivity, are expected yield significant improvements SPECT. Geometric calculations show commercially available cast promise meet these requirements.