Explora fdg4 module

¹⁸F-FDG was produced automatically by cyclotron (Siemens CTI RDS Eclipse ST, Knoxville, Tennessee, USA) using the Explora FDG4 module in our center, and the radiochemical purity was over 95%. All patients fasted at least 6 h and the venous blood glucose levels were maintained under 10 mmol/L before ¹⁸F-FDG injection (7.4 MBq/kg). Patients were required to be quiet after injection for approximately 1 h. Siemens biograph 16HR PET/CT scanner (Knoxville, Tennessee, USA) was performed for scanning. The transaxial intrinsic spatial resolution was 4.1 mm (full-width at half-maximum) in the center of the view. CT scanning (120 kV, 80–250 mA, pitch 3.6, rotation time 0.5) from the proximal thighs to the head was first performed for data acquisition, following by a PET emission scan. The acquisition time was 2–3 min/bed. PET image data sets were iteratively reconstructed using the attenuation correction of CT data, and the infused images were displayed on a workstation. The reconstructed images were then converted to a semiquantitative image corrected by the injection dose and the subject’s body weight (SUV).

¹⁸F-FDG was produced automatically by a cyclotron (RDS Eclips ST; Siemens) and an Explora FDG4 module (Siemens) in our center. All patients were required to fast for at least 6 h to ensure glucose blood levels below 10 mmol/L. Scanning was initiated 1 h after administration of the tracer (7.4 MBq/kg). The data acquisition procedure was as follows: CT was first performed, from the proximal thighs to head, with 120 kV, CARE Dose 4-dimensional mode, 80-250 mA, and a pitch of 3.6. Immediately after CT, a PET emission scan that covered the identical transverse field of view was obtained. The acquisition time was 2-3 min per table position. PET image datasets were reconstructed iteratively by application of the CT data for attenuation correction, and coregistered images were displayed on a workstation.

¹⁸F-FMISO was produced using a modified Explora FDG4 module (Siemens) at SPHIC. For evaluation of the hypoxia status of tumors, micro-PET/CT (Inveon Siemens) scanning was performed on the day before irradiation treatment with an injection of 5.55 MBq (150 μCi) of ¹⁸F-FMISO through the tail vein (Figure 1). ¹⁸F-FMISO was injected 4 h before the scan (36 (link)). Isoflurane was utilized 10 minutes before the scan, and mice were kept under anesthesia during the period of scan. The images were reconstructed with a three dimensional ordered-subset expectation maximization (OSEM3D)/maximum algorithm. The region of interest (ROI) was manually delineated to cover the entire tumor on fused images for data analysis. A similar circular ROI was drawn on the muscle of the opposite hind leg of the mouse on fused images. In order to evaluate the uptake of ¹⁸F-FMISO in tumors, the maximum standardized uptake value (SUVmax) was calculated by measuring the maximal concentration of radioactivity in ROI. The tumor tissue SUVmax (T), the contralateral normal muscle SUVmax (N), and the ratio of the two values (T/N) were calculated.