Gemini tf 64 pet ct scanner

We acquired [¹⁸F]FDG PET/CT images under the following conditions. Before PET/CT, the patient fasted for >6 h and was injected with 5.18 MBq/kg (0.14 mCi/kg) of [¹⁸F]FDG. The blood glucose level was controlled to be <8.33 mmol/L (150 mg/dL). PET/CT images were acquired approximately 60 min after [¹⁸F]FDG injection using a Gemini TF 16 PET/CT scanner (Philips Healthcare, Cambridge, MA, USA) and Gemini TF 64 PET/CT scanner (Philips Healthcare, Cambridge, MA, USA). After the initial low-dose CT (120 kVp, 50 mAs, 4 mm slice thickness) scan, PET images were acquired in 3D mode from the skull base to mid-thigh at 7–10 beds, 2 min each. The PET images were reconstructed using the 3D row-action maximum likelihood algorithm and the iterative ordered subsets expectation maximization algorithm (three iterations, 33 subsets, and no filtering), and CT-based attenuation correction was performed. Kangnam Sacred Heart Hospital and Hallym University Sacred Heart Hospital used PET/CT scanners with the same PET resolution and followed the same PET/CT imaging protocol.

The EARL-compliant imaging protocol was described previously [5 (link)]. All scans were acquired on a Philips Gemini TF-64 PET-CT scanner (Philips Healthcare). Patients were instructed not to eat 4 h prior to each scan. A thoracic field of view was placed such that it contained the primary tumor, using a transmission scan for positioning. A 60-min dynamic PET acquisition started directly after injection of 370 MBq ¹⁸F-FLT in 5 mL saline (flushed with 20 mL saline). Afterwards, a low-dose CT was acquired for attenuation correction (120 kV, 50 mAs). The PET emission scan was binned into 36 frames with varying durations (1 × 10, 8 × 5, 4 × 10, 3 × 20, 5 × 30, 5 × 60, 4 × 150, 4 × 300, and 2 × 600 s). Images were reconstructed with a time-of-flight 3D row action maximum likelihood algorithm (3 iterations, 33 subsets), as provided by the vendor, with corrections for Compton scatter, random coincidences, attenuation, and decay. PET image dimensions were 144 × 144 × 45 voxels with voxel dimensions of 4 × 4 × 4 mm. Venous blood samples were drawn at 5, 10, 20, 30, 40, and 60 min post-injection of ¹⁸F-FLT. From each sample, the whole blood and plasma activity concentrations and parent fractions were measured.

This retrospective study included 6,462 consecutive patients (3,623 men and 2,839 women; mean age ± SD, 61.6 ± 16.2 years; range 2–92 years) who underwent whole-body FDG PET-CT with either Scanner 1 (n = 5,641) (Biograph 64 PET-CT scanner; Asahi-Siemens Medical Technologies, Tokyo) or Scanner 2 (n = 821) (GEMINI TF64 PET-CT scanner; Philips Japan, Tokyo) at our institute between January 2015 and August 2017. When the same patient was scanned more than once, only the first scan was included. The Institutional Review Board approved the study (#017-0365), waiving the requirement for written informed consent from each patient because of the study’s retrospective nature. We confirmed that all methods were carried out in line with the relevant guidelines and regulations.

Studies were performed on a GEMINI TF-64 PET/CT scanner (Philips Healthcare, Best, the Netherlands) [29 (link)]. A 60-min emission scan was started simultaneously with the injection of 370 MBq [¹¹C]HED, administered as a 5-mL bolus (0.8 mL · s⁻¹) followed by a 35-mL saline flush (2 mL · s⁻¹). This emission scan was followed immediately by a respiration-averaged low-dose CT (LD-CT) scan (55 mAs, rotation time 1.5 s, pitch 0.825, collimation 16 × 0.625, acquiring 20 cm in 37 s compared to 5 s for a regular LD-CT) during normal breathing.
Images were reconstructed into 36 frames (1 × 10, 8 × 5, 4 × 10, 3 × 20, 5 × 30, 5 × 60, 4 × 150, 4 × 300, 2 × 600 s) using the 3D row action maximum likelihood algorithm and applying all appropriate corrections for scanner normalization, dead time, decay, scatter, randoms and attenuation based on the corresponding LD-CT scan.

All patients underwent ¹⁸F-FDG PET/CT on a Gemini TF 64 PET/CT scanner (Philips, The Netherlands) [22 (link)]. PET images were iteratively reconstructed using CT-based attenuation correction.
The ¹⁸F-FDG SUV was calculated as [(decay-corrected activity/tissue volume)/(injected dose/body weight)][22 (link)]. SUVmax-T and SUVmax-N were defined as the value of the most intense voxel within the region of interest by visually placing the volume of interest.

All patients underwent ¹⁸F-FDG-PET/CT on a Gemini TF 64 PET/CT scanner (Philips, The Netherlands) according to a previously published protocol [12 (link)]. Radiochemical purity of ¹⁸F-FDG exceeded 95% when manufactured by HM-10 cyclotrons. All patients fasted ≥ 6 h before undergoing ¹⁸F-FDG-PET/CT scanning. Serum blood glucose level was 3.9 to 6.5 mmol/L before ¹⁸F-FDG was intravenously administered at a dose of 148 to 296 MBq. Patients rested for 40 to 60 min in a dimly lit room before PET/CT scan. CT scanning was performed from the head to the proximal thigh and the scan slice thickness was 4 mm. An iterative reconstruction algorithm based on ordered-subset expectation maximization was used to reconstruct the PET images following the CT-based attenuation correction.
The FDG standardized uptake value (SUV) was measured based on the region of interest (ROI) of tumor, which was calculated as [(decay-corrected activity/tissue volume)/(injected dose/body weight)]. Primary tumors and recurrent lesion were delineated using the SUV thresholds of 2.5 according to previous studies [15 (link), 16 (link)]. Maximum SUV (SUVmax) was defined as the value of the most intense voxel within the region of interest. The volume of high FDG uptake was defined within the primary lesion as the 50% isocontour of the SUVmax (SUV50%max).