Ge discovery ste pet ct scanner

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.

Ground truth was defined using patient datasets consisting of 60 min fluorodeoxyglucose (¹⁸F-FDG) dynamic acquisitions of 22 patients with non-high-grade (grades 1 and 2), estrogen receptor positive (ER+) primary breast cancer pre- and post-therapy, as previously described (Wangerin et al 2015 (link)). Patient characteristics are summarized in table 3. The patient scans were performed on a GE Discovery STE PET/CT Scanner (GE Healthcare, Waukesha, WI). The dynamic data were acquired with frames of 16 × 5 s, 7 × 10 s, 5 × 30 s, 5 × 60 s, 5 × 180 s, 7 × 300 s. The data were reconstructed using 3D OSEM with 28 subsets, six iterations, and a 7 mm transaxial Gaussian post-filter. The image voxel size was 4.3 × 4.3 mm transaxially and 3.3 mm axially. The tumor and normal breast tissue regions-of-interest (ROIs) were 3 × 3 × 3 voxels (1.6 cc). The normal breast tissue ROI was placed in the most homogeneous portion in successive tissue in the contralateral breast. We note here that while partial volume effects, as described in Soret et al (2007) (link), were present in the estimate of SUV, the tumors were not expected to significantly change in size between the pre- and post-therapy scans (average time = 20 d) when treated with hormonal therapy. Thus, partial volume correction methods were not evaluated.

All participants underwent interictal FDG-PET scanning using a GE Discovery STE PET/CT scanner (GE Medical Systems, Milwaukee, WI). The scanner has a 15 cm field-of-view and generates 47 image planes with a slice thickness of 3.1 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. Intravenous injection of 5.29 MBq/kg of FDG was followed by a 30-minute uptake period. EEG was monitored throughout the tracer uptake period to ensure interictal images. Forty minutes post injection, a static 20-minute emission scan was acquired parallel to the canthomeatal plane.