Direct comparison of brain [18F]FDG images acquired by SiPM-based and PMT-based PET/CT: phantom and clinical studies

Abstract

Background: Silicon photomultiplier-positron emission tomography (SiPM-PET) has better sensitivity, spatial resolution, and timing resolution than photomultiplier tube (PMT)-PET. The present study aimed to clarify the advantages of SiPM-PET in 18F-fluoro-2-deoxy-D-glucose ([18F]FDG) brain imaging in a head-to-head comparison with PMT-PET in phantom and clinical studies.Methods: Contrast was calculated from images acquired from a Hoffman 3D brain phantom and image noise and uniformity were calculated from images acquired from a pool phantom using SiPM- and PMT-PET. Sequential PMT-PET and SiPM-PET [18F]FDG images were acquired over a period of 10 min from 22 controls and 10 patients. All images were separately normalized to a standard [18F]FDG PET template, then mean standardized uptake values (SUVmean) and Z-score were calculated using MIMneuro and CortexID Suite, respectively.Results: Image contrast, image noise, and uniformity in SiPM-PET changed 19.2%, 3.5%, and -40.0% from PMT-PET, respectively. These physical indices of both PET scanners satisfied the criteria for acceptable image quality published by the Japanese Society of Nuclear Medicine of contrast > 55%, CV ≤ 15% and SD ≤ 0.0249, respectively. Contrast was 70.0% for SiPM-PET without TOF and 59.5% for PMT-PET without TOF. The TOF improved contrast by 3.5% in SiPM-PET. The SUVmean using SiPM-PET was significantly higher than PMT-PET and did not correlate with a time delay. Z-scores were also significantly higher in images acquired from SiPM-PET (except for the bilateral posterior cingulate) than PMT-PET because the peak signal that was extracted by the calculation of Z-score in CortexID Suite was increased. The hypometabolic area in statistical maps was reduced and localized using SiPM-PET. The trend was independent of whether the images were derived from controls or patients.Conclusions: The improved spatial resolution and sensitivity of SiPM-PET contributed to better image contrast and uniformity in brain [18F]FDG images. The SiPM-PET offers better quality and more accurate quantitation of brain PET images. The SUVmean and Z-scores were higher in SiPM-PET than PMT-PET due to improved PVE. [18F]FDG images acquired using SiPM-PET will help to improve diagnostic outcomes based on statistical image analysis because SiPM-PET would localize the distribution of glucose metabolism on Z-score maps.

High-Resolution Silicon Photomultiplier Time-of-Flight Dedicated Head PET System for Clinical Brain Studies

“…Because the wbPET scanner used in this study was not a silicon photomultiplier PET system, it may be argued that it would have high spatial resolution. However, the resolutions of the silicon photomultiplier PET/CT Discovery MI, Digital Biograph Vision PET/CT System, and the Philips Vereos PET/CT System are also approximately 4 mm FWHM (18)(19)(20)(21). Moreover, even if the resolution of the silicon photomultiplier PET scanner is compared with that of the wbPET scanner, there will not be a significant impact on the results of this study because the resolution of the dhPET system is less than 3 mm FWHM (10).…”

Diagnostic performance of a novel high-resolution dedicated axillary PET system in the assessment of regional nodal spread of disease in early breast cancer

“…Each square-shaped detector plane is designed 20 cm × 20 cm in size and composed of 16 units of "double-sided front-end readout modules (DRM)" that integrate the LYSO crystal arrays and 2 SiPM arrays frontend electronics in a compact detector module. In order to deliver better sensitivity, spatial resolution, and timing resolution, a SiPM is used instead of a traditional photomultiplier tube (PMT) (9). By measuring light signals to compare the ratio between light outputs detected at one side and both sides, the double-sided module design has an advantage in providing continuous DOI information with better DOI resolution.…”

“Occipital Pole” Sign on 18F-FDG PET for Dementia With Lewy Bodies and Posterior Cortical Atrophy

“…C , Image shows a 3-dimensional reconstruction of the posterior areas of the brain, obtained by the Cortex ID Suite (GE Healthcare), a fully automated tool for analysis and quantification of 18 F-FDG brain PET examinations, 1,2 and includes SUV ratio reference databases generated from healthy volunteer data. This software application provides 3D stereotactic surface projection maps, which improve the accuracy and sensitivity of decision-making 3–6 . PET coregistration and fusion display capabilities with CT and MR allow PET findings to be related to brain anatomy.…”

“…This software application provides 3D stereotactic surface projection maps, which improve the accuracy and sensitivity of decision-making. [3][4][5][6] PET coregistration and fusion display capabilities with CT and MR allow PET findings to be related to brain anatomy. The FDG reference regions include the pons and the pan cerebellar region.…”

“…This could involve the risk of not capturing the metabolic sparing of PVC with respect to the lateral occipital (visual association) cortex. The saving of PVC compared with the lateral occipital cortex can be better appreciated by capturing the posterior projection of the PVC in a 3D stereotactic surface projection map, [1][2][3][4][5][6] and we propose the name of "occipital pole" sign for this evidence.…”