Biograph mct system

Before the ¹⁸F-FDG PET/CT imaging, all the study participants had to fast for at least 6 h. The scans were performed using a Biograph mCT system (Siemens Medical Solutions, Malvern, PA, USA). The system consisted of a four-ring PET scanner with a transaxial field of view of 70 cm, an axial field of view of 22.1 cm, and a 40-section CT scanner. Subsequently, 50–70 min following the injection of ¹⁸F-FDG (370 MBq), PET scans were performed from the vertex to the mid-thigh. The scanning time per table position was 1.5 min and the imaging matrix size was 200 × 200. All the patients had a plasma glucose level of <150 mg/dL before the ¹⁸F-FDG injection. Before the PET scan, a standard helical CT scan was performed from the head to the proximal thighs using the manufacturer’s dose reduction software. The preset was 120 kV with 40 × 0.6 mm collimation, a pitch of 1.5, and a 2 mm slice thickness. No intravenous iodinated contrast agent was administered. We reconstructed the PET images using an ordered subsets expectation maximization iterative reconstruction algorithm (two iterations, 21 subsets) and the CT data for attenuation correction.

For FDG in BC patients, a whole body PET-CT scan was performed one hour after injection (3–4 MBq/kg IV). For ¹⁸F-dihydroxy-phenylalanine (F-DOPA) in MTC patients, the acquisition started five minutes after injection of tracer (3–4 MBq/kg IV) centering on the metastatic area for ten minutes and one hour after injection, a whole body PET-CT was performed.
PET/CT was performed using a four-ring Siemens Biograph mCT system with time-of-flight capability 60 and 120 min after ⁶⁸Ga-IMP288 injection and reconstructed using a three-dimensional ordinary Poisson ordered-subset expectation maximization with point-spread function correction and time-of-flight mode (three iterations, 21 subsets, 2 mm in full width at half maximum Gaussian post-filtering, and voxel size of 4 × 4 × 2 mm). Whole-body images were acquired under normal tidal respiration for 2.5 min per bed position. CT was performed using variable mAs, 120 kVp, and a pitch of 1 without contrast enhancement. Images were acquired from the top of the head to mid-thigh (six–eight steps per patient). Tumor SUVmax (T-SUVmax) was determined on the most intense focus in the whole-body scan. Tumor burden was analyzed using total tumor volume (TTV).

Patients received [⁶⁸Ga]Ga-PSMA-11-PET/CT imaging approximately one week prior to radioligand therapy. Imaging was performed 60 ± 10 min post-injection (p.i.) on a Biograph mCT system (Siemens Healthineers, Erlangen, Germany) scanning cranium to trochanter major. In this study, these scans were solely used to determine lesion volumes.
After therapy, SPECT/CT and planar imaging was performed at 1, 24, 48, 72 and 168 h on either a Symbia T16 or Symbia Intevo Bold system (Siemens Healthineers, Erlangen, Germany). SPECT/CT scans were acquired at three body regions to include lesions and organs at risk: the pelvis, abdomen, and head-neck region. Acquisition and reconstruction parameters of PET/CT, SPECT/CT and planar imaging can be found in Additional file 1.