Vereos digital pet ct

All of the patients fasted for at least 6 h before the MET-PET examination. The patients were intravenously injected with [¹¹C]methionine at a dose of 370 MBq/kg body weight and hydrated with 0.9% sodium chloride. Physical activity was kept to a minimum, with a rest period of 10 min post-injection. At 10 min after injection, PET was performed using a PET/computed tomography system (Vereos Digital PET/CT; Philips, Amsterdam, The Netherlands) CT unit and a PET scanner with 23,040 lutetium-yttrium oxyorthosilicate (LYSO) crystals in 64 rings. After that, the patients were intravenously injected with [¹⁸F]deoxyglucose at a dose of 4.4 MBq/kg body weight, and PET was performed the same as above.
A low-amperage CT scan was acquired for the attenuation correction of the PET images (213 mA, 120 kV, and CT slice thickness of 5 mm). The CT dose index for low-dose CT was 10.7 mGy. After non-enhanced CT, a total-body PET examination in the caudocranial direction from the upper thighs to the vertex was performed (2 min per bed). Reconstruction was performed using the 3D reconstruction method of ordered subset expectation maximization with 30 subsets and two iterations.
The images were reviewed by a nuclear physician. The standard uptake values (SUV) of the target lesions were measured.

The software was validated using the commercially available NEMA-2012 PET phantom (NEMA-2012). The NEMA-2012 phantom contains six spheres with a known diameter, making it suitable for validation of segmentations in the 3DeliverS software. CT scans of the phantom were already available and were acquired with the Philips Vereos Digital PET/CT, Philips Eindhoven, the Netherlands. The in-plane resolution of the scan was 1.17 mm × 1.17 mm with a slice thickness of 0.67 mm. All spheres were segmented by two independent observers (AB and TO). Segmentation was performed by manually delineating at least the smallest and largest axial contours, using a B-spline contour algorithm. Interpolation was used to calculate all in-between contours. Subsequently, the interpolated contours were manually checked to be located on the inside edges of the spheres. Contours which were not located on the inside edges were manually corrected by the observer, followed by recalculation of the interpolation. This process was repeated until the observer was satisfied with the segmentation result. After segmentation, the contours were converted into a 3D model. The largest axial diameter and 3D volume were then extracted from 3DeliverS, and compared with the specifications according to the manufacturer.

[¹⁸F]MK-6240 (Cerveau Technologies, Knoxville TN) is an investigational drug studied as a second-generation cerebral tau tangles imaging agent.
Ninety minutes after intravenous administration of [¹⁸F]MK-6240 (target activity 185 ± 5 MBq) a 30-min dynamic list-mode acquisition was performed on a Philips Vereos digital PET-CT (Philips Healthcare, Amsterdam Netherlands). Images were reconstructed using manufacturer’s reconstruction algorithm which includes attenuation, scatter, and decay corrections, and time-of-flight information. Point spread function (PSF) and 1 mm re-slicing was also computed using the manufacturer’s algorithm to obtain a better resolution recovery [16 ].