Ge discovery mi pet ct

Prior to the imaging, subjects were required to fast for 6 h and have a blood glucose level ≤ 200 mg/dL to ensure proper uptake of the glucose tracer. Before imaging, 5 mCi ± 10% FDG was injected intravenously, and tracer uptake was completed while the subject lay supine in a dark room with their eyes open and their ears unplugged with no external stimuli. Imaging paralleled that employed in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) protocols (i.e., 30 min of imaging commencing at 30 min post-injection in 5 min frames) [25 (link)]. Attenuation correction computed tomography (CT) and PET emission imaging were performed on a GE Discovery MI PET/CT (GE Healthcare, Chicago, IL, USA). The PET images were reconstructed using six iterations and 16 subsets (VUE Point HD method) with a 25.6 cm field of view and 192 × 192 matrix size, corrected for motion across acquisition frames, and then averaged across the 30 min. The MRI was captured on a GE SIGNA Premier 3T scanner (GE Healthcare, Waukesha, WI, USA) with a 48-channel head coil. A volumetric coronal T1 MP-RAGE (TI = 900 ms, TE = 2.952 ms, TR = 7.24 s, flip angle = 8°, FOV = 256 × 256 mm, matrix = 256 × 256, bandwidth = 244 Hz/pixel) scan was acquired with a 1.0 mm isotropic spatial resolution.

All data were acquired on a digital GE Discovery MI PET/CT (DMI) system, installed in Ghent University Hospital, Belgium. The investigated system consists of three detector rings; each PET ring uses 136 detector blocks containing a 4 × 9 array of lutetium-based scintillator (LBS) crystals coupled to a 3 × 6 array of silicon photomultipliers (SiPMs) with Anger multiplexing for crystal identification [18 (link)]. Table 1 contains a summary of important design and performance parameters [19 (link)].
Table 1

Design and performance specifications of the GE Discovery MI commercial system

GE Discovery MI	Three detector rings
Axial FOV	15 cm
Patient bore size	70 cm
Photodetector	SiPM
Scintillator	LBSa (LYSO)
Crystal element size	3.95 × 5.3 × 25 mm3
Coincidence timing window	4.9 ns
Sensitivity	7.5 cps/kBq
Spatial resolution (FWHM mm)	Radial/tangential/axial
@1 cm	4.69/4.08/4.68
@10 cm	5.58/4.64/5.83
@20 cm	7.53/5.08/5.47
Scatter fraction	41.7%
Peak NECR	102.3 kcps @ 24.7 kBq/ml
Clinical NECR	29.6 kcps @ 2.4 kBq/ml

^aLutetium-based scintillator

A well-countered cross-calibration scan was performed with ¹⁸F in a uniform cylindrical phantom before starting the tests as a common quality control and assurance procedure.