Minitrace

All reagents and solvents were purchased from Sigma-Aldrich Corporation. No-carrier-added ¹⁸F (half-life 109.8 min) was produced via the [¹⁸O(p,n)¹⁸F] nuclear reaction by a General Electric MINItrace cyclotron (10 MeV proton beam). ¹⁸F-fluorine at the end of a 25-μAh, 60-min (12.5 μAh) irradiation was 16–17 GBq (732–769 mCi). [¹⁸F]DPA-714 was labelled with ¹⁸F-fluoride starting from the corresponding precursor using a tosyloxy-for-fluorine nucleophilic aliphatic substitution as previously described with slight modification [16 (link)]. The specific activity at the end of synthesis and the radiochemical purity of [¹⁸F]DPA-714 obtained within 90 min of radiosynthesis were 300 GBq/μmol and N > 99%, respectively.

All ¹⁸F-PSMA-1007 PET/CT data were acquired on a PET/CT scanner (Gemini 64TF, Philips, Netherlands) at a single location. Radiolabeling was performed using a fully automated radiopharmaceutical synthesis device based on a modular concept (MINItrace, GE Healthcare, USA). Over 99% radiochemical purification yield ¹⁸F-PSMA-1007 was obtained and examined by both radiothin layer chromatography and high-performance liquid chromatography analysis. Patients received intravenous injection of ¹⁸F-PSMA-1007 PET/CT (3.7 MBq/kg body weight), and completed PET and CT scan 90 minutes after the injection. Low-dose CT scans from the head to the proximal thighs (pitch 0.8 mm, 60 mA, 140 kV [peak], tube single turn rotation time 1.0 s and 5-mm slice thickness) for PET attenuation were acquired (pitch 0.8 mm, automatic mA, 140 kV [peak] and 512 × 512 matrix). Whole-body PET scans were performed in three-dimensional mode (emission time: 90 s per bed position, scanned at a total of 7-10 beds) as in our previous study (17 (link)).

¹¹C-CO₂ was produced with a MINItrace cyclotron (GE Healthcare, Piscataway, NJ, USA). ¹¹C-Choline was synthesized using the solid-phase method as described by Pascali et al (14 (link)) in a modified commercial synthesis module (TRACERlab FXc; GE Healthcare). The radiochemical purity of the ¹¹C-Choline was evaluated to be >95% with a high-performance liquid chromatography radiodetector (TRACERlab FXc; GE Healthcare).
All PET scans were obtained using a PET/CT scanner (Discovery LS; GE Healthcare). Each patient was injected with 7.4 MBq/kg of ¹¹C-Choline intravenously 5 min prior to imaging. PET images were captured in the supine position over two bed positions (3 min per position) from the upper neck to the lower edge of the liver, or six bed positions (whole body) when additional imaging revealed distant metastasis. The parameters of the multidetector helical CT scan were 140 kV, 80 mA, 0.8 sec per tube rotation, 5 mm slice thickness, 6:1 pitch and 11.25 mm/sec table speed. PET images were reconstructed with the iterative reconstruction ordered-subset expectation maximization likelihood algorithm of the manufacturer following attenuation correction based on the CT dataset. Consecutive transverse PET/CT slices at 4.25 mm thickness were generated.

¹⁸F-deoxyglucose (¹⁸F-FDG) Positron radioactive tracer was synthesized by medical cyclotron (MINITrace, General Electric Co., Milwaukee, USA) and FX-FN chemosynthesis system (TraceLab, General Electric Co.). Mice were anesthetized by Ether 60 min after tail intravenous injection of 0.2 millicurie (mci) ¹⁸F-FDG and scanned systemically by 2D positron-emission tomography-computed tomography (PET-CT). Figures from PET-CT were analyzed in Xeleris by two experienced radiologists. The abnormal thick, thin, or defect of radioactivity uptake in inoculation site was excluded. Radioactivity uptake from tumor (Target) was divided by uptake from spine (Non-Target) and presented as Target/Non-Target ratio (T/NT).

PET/CT images were obtained on a PET/CT scanner (Gemini 64TF, Philips, Netherlands). A completely automated radiopharmaceutical synthesis equipment based on a modular architecture was used for radiolabeling (MINItrace, GE Healthcare, USA). The radiochemical purification yield of ¹⁸F-PSMA-1007 was over 99% and was tested using both radiothin layer chromatography and high-performance liquid chromatography. Patients underwent a 90-min PET/CT scan after receiving an intravenous injection of ¹⁸F-PSMA-1007 PET/CT (3.7 MBq/kg body weight). Low-dose CT scans were acquired from the head to the proximal thighs for PET attenuation (pitch, 0.8 mm; automatic mA, 140 kV [peak]; tube single turn rotation time, 1.0 s; and 5-mm slice thickness). As in our prior work (13 (link)), whole-body PET scans were conducted in three dimensions (emission time of 90 s per bed position, scanned at a total of 7–10 beds).

All patients underwent ¹⁸F-FDG PET/CT imaging after more than 6 hours of fasting. Before ¹⁸F-FDG injection, the patients’ blood sugar levels were less than 8.3 mmol/L. After intravenous administration of ¹⁸F-FDG 3.7 MBq/kg, the patients rested in a quiet room for 45 to 60 minutes before imaging.
The imaging instrument model was a GE Discovery STE16 (GE Healthcare) and ¹⁸F- FDG was produced by a PET/CT center. The cyclotron's model was a GE Minitrace. The image acquisition ranged from parietal to femoral and when necessary, imaging of lower limbs was also performed. We used 16 row helical CTs through scanning with the following conditions: tube voltage (body 120 kv, craniocerebral 160 kv), tube current (body 110 mA and craniocerebral 260 mA), 3.75 mm thick; PET collection every bed time was 3 minutes, the whole body scanning needed 6 to 7 beds. Using the viewpoint method, the scan data were rebuilt into an image fusion, resulting in transaxial, coronal, and sagittal CT, PET, and PET/CT image fusion.