Tf big bore

Patients were imaged with a PET/CT scanner (TF Big Bore, Philips, Holland). 18F-FDG with a pH value of 5–7 and a radiochemical purity of more than 95% was produced using a cyclotron (MINItrace, GE Healthcare, Milwaukee WI, USA). The patients fasted for at least 6 h and had blood glucose levels below 200 mg/dL prior to the injection of the 18F-FDG. Patients reclined in a quiet room for 60 min after the intravenous injection of 4.4–5.5 MBq/kg of 18F-FDG.
Spiral CT scanning was performed at 120 kVp and 300 mAs, and images were reconstructed as contiguous 5 mm slices. Additional lung reformats were generated with contiguous 1 mm slices. PET was performed after spiral CT, without patient repositioning. PET images were obtained at seven to eight couch positions per patient, with an acquisition time of 1 minute in each position. We used CT scan data for attenuation correction of the PET images and fused the attenuation-corrected PET and CT images.

Imaging of patients was conducted on a PET/CT scanner (TF Big Bore, Philips; and Ingenuity TF, Philips). 18F-FDG with a pH of 5–7 and a radiochemical purity exceeding 95% was produced using a cyclotron (MINItrace, GE Healthcare). The patients underwent fasting for at least 6 h and had blood glucose levels below 200 mg/dL prior to injection with 18F-FDG. Patients were required to lay in a quiet room for 60 min after intravenous injection with 4.4–5.5 MBq/kg 18F-FDG.
Spiral CT scanning was performed at 120 kVp and 300 mA·s. PET was performed after spiral CT without patient repositioning. PET images were obtained at 7 to 8 couch positions per patient, with an acquisition time of 1.5 min per position. We used CT scan data for attenuation correction of PET images and then fused the attenuation-corrected PET and CT images.

Seven adult patients with stage III‐IV nasopharyngeal carcinoma treated with concurrent chemotherapy and IMRT were identified for this study. MRI images extended inferiorly only to the C4 vertebral body to minimize image acquisition time and to assist solely with target delineation of gross disease in the nasopharynx/base of skull. Patients were first simulated on either a PET/CT (TF Big Bore; Philips Healthcare, Andover, MA) or CT scanner (Sensation Open; Siemens Medical Solutions, Malvern, PA) with a voxel size of 1 × 1 × 2 mm3. The same immobilization devices were used to scan the patients on the MRI (Siemens Magnetom Espree 1.5T; Siemens Medical Solutions). A six‐channel body coil was placed over the patient mask and shoulder region in place of the dedicated head coil in order to accommodate the head support and face mask. For purposes of dose calculation, we utilized a 2D axial T1 weighted spin echo sequence with a TR = 755 ms and TE = 12 ms. Vendor software 2D distortion correction option was turned on for all scans. The field of view was 26 cm with a voxel size of 0.51 × 0.51 × 4 mm3.