Biograph 16 scanner

PET/CT examinations were performed on a Biograph 16 scanner (Siemens AG, Germany). Ga-68 DOTATOC was prepared as described by Zhernesekov et al.28 (link) The mean Ga-68 DOTATOC activity administered per patient was 112.5 MBq (median, 106 MBq; range, 66–200 MBq). The PET scan was acquired at approx. 1 hour after administration in 5 – 6 bed positions using a 168 × 168 acquisition matrix. Iterative reconstruction was performed with a scatter correction using the ordered subset expectation maximization technique (OSEM) with 5 iterations and 8 subsets. The transaxial field of view (FOV) was 585 mm and the axial FOV 162 mm. Non-contrast CT or venous phase CT was used for attenuation correction. For the triphasic CT protocol, 80–100 ml Ultravist 370 (Bayer Schering, Germany) was administered, using bolus tracking for acquisition of an arterial phase (approx. 24s delay), a portal venous phase (approx. 45s delay) for an upper abdominal scan with 16 × 0.75 mm slice thickness, and a venous phase (approx. 70s delay) for an upper abdominal scan with 16 × 1.5 mm slice thickness. PET/CT was performed with a triphasic CT protocol in 40 patients, a venous phase alone in 4 patients, and unenhanced CT in 8 patients. The CT dose parameters were: 230 effective mAs and 120 kV.

All patients underwent preoperative [¹⁸F]FDG-PET/CT scanning using a Biograph 16 scanner (Siemens Medical Solutions, Erlangen, Germany). The Biograph 16 consists of a 16-slice CT detector and a Lu2SiO5[Ce] crystal block, which were periodically inspected four times a year. The PET scanner field of view had an 830-mm ring diameter and a 162-mm axial length. The patient was fasting for 6 h prior to the examination^{34 (link)}. The injected activity was 3 MBq/kg of [¹⁸F]FDG, and PET scans were acquired from the parietal to the proximal thigh at 2 min on bed position, 60 min after injection. PET images were reconstructed using iterative reconstruction (iterations: 2, subsets: 8). Noise reduction was performed by smoothing the images with a Gaussian filter (full width at half maximum, 5 mm). Whole-body CT scans were acquired with patients in the supine position, from the parietal to the proximal thigh (120 kVp; 100 mA in auto mA mode). All data were subjected to attenuation correction based on CT data. The scatter correction followed a single-scatter simulation method.