Small animal pet scanner

The PET scanning was carried out using a small-animal PET scanner (Siemens Medical Solutions USA, Knoxville, TN, USA). Mice (7–8 weeks old, 30.1 ± 1.4 g, n = 3) were anesthetized using 1.5% (v/v) isoflurane and treated according to the protocol reported previously [28 (link),29 (link)]. Mice were intravenously injected via the tail vein with [¹¹C]BPTES (14–16 MBq, 0.3 mL) and a 90 min scan was conducted immediately. The time frame reconstruction was as follows: 1 min × 4 frames, 2 min × 8 frames, and 5 min × 12 frames. The obtained dynamic PET images were reconstructed by filtered-back projection using a Hanning filter, with a Nyquist cutoff of 0.5 cycles per pixel. The time–activity curves (TACs) of [¹¹C]BPTES were acquired using PMOD software (version 3.4, PMOD Technology, Zurich, Switzerland) from the volumes of interest, which were manually mapped onto the liver, kidney, lung, brain and heart. The radioactivity was decay-corrected to the injection time and presented as a standardized uptake value (SUV), which was normalized for injected radioactivity and body weight. The SUV was calculated as follows: SUV = (radioactivity per milliliter tissue/injected radioactivity) × body weight (g). All PET quantitative data are expressed as the mean ± standard deviation (SD).

A PET/CT measurement was performed on each mouse model 8 weeks after GC cells injection. All scans were performed using a small-animal PET scanner (Siemens Healthcare, USA). In all, 10 MBq/0.1–0.2 mL ¹⁸F-FDG was injected via a tail-vein catheter after anesthetization. PET data were obtained 20 min followed by a delay of 40 min for FDG uptake. In fused PET images, the maximum standardized uptake value (SUV_max) was calculated from the maximum voxel value (Bq/mL) in the volume of interest.