Dynamic PET imaging acquisition

Patients were instructed to fast, except for clear fluids, 12 h prior to the PET scan and to drink 500 mL of water 30 min prior to scan. No diuretics were used. Dynamic [¹⁸F]FCH and [¹⁸F]DCFPyL PET imaging was performed on a Discovery VCT (GE Healthcare, Waukesha, WI, USA) PET/CT scanner. A low-dose CT scan for attenuation correction and anatomical correlation was taken first with patients lying supine on the patient couch using the following technique: 50 mAs, 120kVp, without intravenous contrast, 47 slides with 3.27-mm spatial interval. The dynamic PET scan was set to cover the whole prostate and common iliac arteries. It was started simultaneously as the intravenous injection of 4 MBq/kg (median 381 MBq; range 280–538 MBq) [¹⁸F]FCH or 325 MBq (median 335 MBq; 280–348 MBq) [¹⁸F]DCFPyL without the patient moving from the CT scan position. The dynamic PET scan was acquired for 22 min under quiet breathing with variable frame lengths of 10 s (10 frames), 20 s (5), 40 s (4), 60 s (4) and 180 s (4). SUV of [¹⁸F]FCH or [¹⁸F]DCFPyL was measured by averaging the last four dynamic PET images, which was equivalent to 12 min of acquisition starting at 10 min post-injection. Both [¹⁸F]FCH and [¹⁸F]DCFPyL were obtained from the Centre for Probe Development and Commercialization (Hamilton, ON, Canada) at arm’s length.