“…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).…”
Section: Discussionmentioning
confidence: 87%
“…Detailed basic specifications of the dhPET system are described elsewhere (10). This TOF-PET system for the head and breast is designed to be less expensive than the conventional wbPET system but with higher sensitivity and spatial resolution.…”
We acquired brain positron emission tomography (PET) images of fluorodeoxyglucose (FDG) and flutemetamol PET using a time-of-flight-PET system dedicated for the head (dhPET) and a conventional whole-body PET/computed tomography (wbPET) system and evaluated the clinical superiority of dhPET over wbPET. Methods: There were 18 subjects for the FDG-PET study and 17 subjects for the flutemetamol PET study. FDG-PET images were first obtained using wbPET, followed by dhPET. Flutemetamol PET images were first obtained using wbPET, followed by dhPET. Images acquired using dhPET and wbPET were compared by visual inspection, voxelwise analysis, and standard uptake value ratio (SUVR). Results: All FDG and flutemetamol images acquired using dhPET were judged as better by visual inspection than those acquired using wbPET. The voxel-wise analysis demonstrated that accumulations in the cerebellum, lateral occipital cortices, and around the central sulcus area in dhPET FDG images were lower than those in wbPET FDG images, whereas accumulations around the ventricle systems were higher in dhPET FDG images than those in wbPET FDG images. Accumulations in the cerebellar dentate nucleus, midbrain, lateral occipital cortices, and around the central sulcus area in dhPET images were lower than those in wbPET images, whereas accumulations around the ventricle systems were higher in dhPET flutemetamol images than those in wbPET flutemetamol images. Mean cortical SUVRs of FDG and flutemetamol dhPET images were significantly higher than those of FDG and flutemetamol wbPET images, respectively. Conclusion: The dhPET images had better image quality by visual inspection and higher SUVRs than wbPET images. Although there were several regional accumulation differences between dhPET and wbPET images, understanding this phenomenon will enable full use of the features of this dhPET system in clinical practice.
“…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).…”
Section: Discussionmentioning
confidence: 87%
“…Detailed basic specifications of the dhPET system are described elsewhere (10). This TOF-PET system for the head and breast is designed to be less expensive than the conventional wbPET system but with higher sensitivity and spatial resolution.…”
We acquired brain positron emission tomography (PET) images of fluorodeoxyglucose (FDG) and flutemetamol PET using a time-of-flight-PET system dedicated for the head (dhPET) and a conventional whole-body PET/computed tomography (wbPET) system and evaluated the clinical superiority of dhPET over wbPET. Methods: There were 18 subjects for the FDG-PET study and 17 subjects for the flutemetamol PET study. FDG-PET images were first obtained using wbPET, followed by dhPET. Flutemetamol PET images were first obtained using wbPET, followed by dhPET. Images acquired using dhPET and wbPET were compared by visual inspection, voxelwise analysis, and standard uptake value ratio (SUVR). Results: All FDG and flutemetamol images acquired using dhPET were judged as better by visual inspection than those acquired using wbPET. The voxel-wise analysis demonstrated that accumulations in the cerebellum, lateral occipital cortices, and around the central sulcus area in dhPET FDG images were lower than those in wbPET FDG images, whereas accumulations around the ventricle systems were higher in dhPET FDG images than those in wbPET FDG images. Accumulations in the cerebellar dentate nucleus, midbrain, lateral occipital cortices, and around the central sulcus area in dhPET images were lower than those in wbPET images, whereas accumulations around the ventricle systems were higher in dhPET flutemetamol images than those in wbPET flutemetamol images. Mean cortical SUVRs of FDG and flutemetamol dhPET images were significantly higher than those of FDG and flutemetamol wbPET images, respectively. Conclusion: The dhPET images had better image quality by visual inspection and higher SUVRs than wbPET images. Although there were several regional accumulation differences between dhPET and wbPET images, understanding this phenomenon will enable full use of the features of this dhPET system in clinical practice.
“…Another disadvantage of dbPET is that the mammary gland near the chest wall may sometimes be outside the FOV of dbPET compared to MRI. A new ring-shaped PET scanner with a larger detector diameter than ours has been developed [ 24 ]; it may solve this issue, i.e., reduce blind areas.…”
Purpose
To evaluate the clinical feasibility of high-resolution dedicated breast positron emission tomography (dbPET) with real low-dose 18F-2-fluorodeoxy-d-glucose (18F-FDG) by comparing images acquired with full-dose FDG.
Materials and methods
Nine women with no history of breast cancer and previously scanned by dbPET injected with a clinical 18F-FDG dose (3 MBq/kg) were enrolled. They were injected with 50% of the clinical 18F-FDG dose and scanned with dbPET for 10 min for each breast 60 and 90 min after injection. To investigate the effect of the scan start time and acquisition time on image quality, list-mode data were divided into 1, 3, 5, and 7 min (and 10 min with 50% FDG injected) from the start of acquisition and reconstructed. The reconstructed images were visually and quantitatively compared for contrast between mammary gland and fat (contrast) and for coefficient of variation (CV) in the mammary gland.
Results
In visual evaluation, the contrast between the mammary gland and fat acquired at a 50% dose for 7 min was comparable and even better in smoothness than that in the images acquired at a 100% dose. No visual difference between the images with a 50% dose was found with scan start times 60 and 90 min after injection. Quantitative evaluation showed a slightly lower contrast in the image at 60 min after 50% dosing, with no difference between acquisition times. There was no difference in CV between conditions; however, smoothness decreased with shorter acquisition time in all conditions.
Conclusions
The quality of dbPET images with a 50% FDG dose was high enough for clinical application. Although the optimal scan start time for improved lesion-to-background mammary gland contrast remained unknown in this study, it will be clarified in future studies of breast cancer patients.
“…During data acquisition, both prompt and delayed events are saved in list-mode format, and a 3D image is reconstructed at an isotropic voxel size of 1.1 mm with a matrix size of 240 (X) × 240 (Y) × 148 (Z). Attenuation and scatter correction are performed with a modified maximum-likelihood attenuation correction factor and single scatter simulation without external radiation exposure [ 13 ]. Fig.…”
Background
This study evaluated the physical performance of a positron emission tomography (PET) system dedicated to the head and breast according to the National Electrical Manufacturers Association (NEMA) NU2-2012 standard.
Methods
The spatial resolution, sensitivity, scatter fraction, count rate characteristics, corrections for count losses and randoms, and image quality of the system were determined. All measurements were performed according to the NEMA NU2-2012 acquisition protocols, but image quality was assessed using a brain-sized phantom. Furthermore, scans of the three-dimensional (3D) Hoffmann brain phantom and mini-Derenzo phantom were acquired to allow visual evaluation of the imaging performance for small structures.
Results
The tangential, radial, and axial full width at half maximum (FWHM) at a 10-mm offset in half the axial field of view were measured as 2.3, 2.5, and 2.9 mm, respectively. The average system sensitivity at the center of the field of view and at a 10-cm radial offset was 7.18 and 8.65 cps/kBq, respectively. The peak noise-equivalent counting rate was 35.2 kcps at 4.8 kBq/ml. The corresponding scatter fraction at the peak noise-equivalent counting rate was 46.8%. The peak true rate and scatter fraction at 8.6 kBq/ml were 127.8 kcps and 54.3%, respectively. The percent contrast value for a 10-mm sphere was approximately 50%. On the 3D Hoffman brain phantom image, the structures of the thin layers composing the phantom were visualized on the sagittal and coronal images. On the mini-Derenzo phantom, each of the 1.6-mm rods was clearly visualized.
Conclusion
Taken together, these results indicate that the head- and breast-dedicated PET system has high resolution and is well suited for clinical PET imaging.
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