PET sessions were performed with an ECAT 951/31 camera (Siemens/CTI, Knoxville, USA). A transmission scan of 20 minutes to correct for attenuation was obtained immediately before the emission scan. The spatial resolution of the camera was 5 mm. in the center of the field of view. TYR was administered as a one minute bolus via a MEDRAD MCT Plus infusion pump. Axial images with a slice thickness of 3mm. were made of the head and neck area. A region of interest (ROI) was drawn around the hot spot in the sella turcica by hand on the relevant planes and the volume of the ROI and the PSR in the ROI were calculated.
All PET-measurements were determined twice, immediate after imaging and at the time of completion of this study, with no discrepancies in measured volumes and PSR between the first and second measurements.