Exact hr pet scanner

The details of FDG-PET acquisition and data analysis have been described previously (Alkonyi et al., 2011 (link)). In brief, all PET scans were acquired using an EXACT/HR PET scanner (CTI/Siemens, Hoffman Estates, IL, U.S.A.), which provides simultaneous acquisition of 47 contiguous transaxial images with a slice thickness of 3.125 mm. The reconstructed image resolution was 5.5 ± 0.35 mm at full width at half-maximum (FWHM) in-plane and 6.0 ± 0.49 mm at FWHM in the axial direction. Scalp EEG was monitored in all children during the tracer uptake period. 0.143 mCi/kg of FDG was injected intravenously as a slow bolus followed by a 30-min uptake period. Forty minutes after injection, a static 20-min emission scan was acquired. Calculated attenuation correction was applied to the images using automated threshold fits to the sinogram data. Based on the EEG data and clinical observation, all PET scans were acquired in the interictal state.

All FDG-PET scans were obtained in the interictal state, using either the EXACT/HR PET scanner (CTI/Siemens, Hoffman Estates, IL, USA), or the GE Discovery STE PET/CT scanner (GE Medical Systems, Milwaukee, WI), both located at the PET Center, Children’s Hospital of Michigan. The difference between the two scanners was an isotropic image resolution of 5.5 ± 0.35mm at full-width at half-maximum (FWHM) on the Siemens scanner and 6.0 ± 0.5mm at FWHM on the GE Discovery scanner. For both scanners, 47 axial image planes were obtained, with a slice thickness of 3.125mm. Four hours of fasting was required prior to the procedure. Intravenous slow bolus of 0.143mCi/kg of FDG was injected, followed by a 30-minute uptake period. Continuous scalp EEG monitoring was performed during tracer uptake. External stimuli were minimized during this time by asking the patients to lie quietly in a semi-dark room with their eyes closed. The children were positioned in the scanner 40 minutes after FDG injection, and a static 20-minute emission scan of the brain was acquired. Automated threshold fits to sinogram data were used to calculate the attenuation correction which was then applied to the brain images. After the tracer uptake period (but not during the uptake period), sedation was used when necessary.