Biograph 40 truev hd

A gross activity of 206.7 ± 12.7 MBq of FMM (Vizamyl; GE Healthcare) was measured 3.9 ± 3.0 min before dose administration. A noncontrast low-dose CT scan was performed for attenuation correction in the PET/CT scanner (Biograph 40 TrueV HD; Siemens). A PET list-mode acquisition was performed starting at the time of FMM administration. Data were acquired for 8 min and rebinned to dynamic datasets of 4 × 2 min without attenuation correction for motion checking only. The early-phase images were initially iteratively reconstructed to a 168 × 168 matrix, with three iterations, 21 subsets, zoom 2 and Gaussian filter 2 mm using attenuation, scatter and point spread function correction. After an uptake time of 90.6 ± 5.1 min, late-phase data were acquired for 20 min and reconstructed to a 168 × 168 matrix, with the other parameters as given above including rebinning into dynamic sequences for motion checking. After initial experience with the first 25 investigations, we shortened the late-phase acquisition time from 20 min to 10 min due to frequent patient motion in the late phase of the acquisition. We also changed the reconstruction matrix from 168 × 168 to 128 × 128 (with the other parameters as given above) to achieve a low level of noise without apparent loss of diagnostic image quality.

The PET images were acquired using a Biograph 40 TrueV HD PET/CT scanner (Siemens Healthineers AG, Erlangen, Germany) in the Department of Nuclear Medicine and PET Centre, Na Homolce Hospital. The participants received a single intravenous dose of flutemetamol (18F; Vizamyl, GE Healthcare, Chicago, IL). Non-contrast low-dose CT brain images were acquired for attenuation correction prior to the PET scans. A PET list-mode acquisition was performed in two phases: early (perfusion) and late (β-amyloid). The early-phase images were acquired at the time of flutemetamol (18F) administration for 8 min and rebinned into dynamic datasets of 2 × 4 min for motion checking. The late-phase images were acquired 90 min after flutemetamol (18F) administration for a total of 10 min (2 × 5 min). Flutemetamol (18F) PET images were visually read (as positive or negative) by a certified nuclear medicine specialist using the GM-EDGE method [60 (link)].