Fastlab synthesis module

[¹⁷⁷Lu]Lu-DOTAGA-OncoFAP was synthesized in an FASTlab synthesis module (GE Healthcare), at different molar activities ranging from 44 to 105 GBq/µmol. The configuration of the cassette is presented in Figure S7 of the Supplementary Material. Carrier-free Lutetium-177 (EndolucinBeta^® 40 GBq/mL—pharmaceutical precursor, solution) with a concentration activity of 37 MBq/µL in a volume of 0.5 mL acetate buffer at pH 4.5 is transferred to the reactor vial. The reaction was scaled down to an amount of DOTAGA-OncoFAP ranging from 5.1 to 13.3 µg, which was dissolved in acetate buffer (1 mL, 0.1 M pH 4.5 TRASIS ALLinONE reagent kit) and aspirated into the reactor vessel. The solution was stirred for 30 min at 90 °C under gentle nitrogen flow, then loaded for purification onto the preactivated C18 cartridge, washed with 5 mL of 0.9% NaCl solution and eluted with eluent solution made of 700 µL of absolute ethanol (TRASIS ALLinONE reagent kit) and 800 µL of water for injection (WFI, Fresenius kabi). The product was diluted with 0.9% NaCl solution to obtain the final formulation. Further, the radiolabeling was also performed by adding 20 mg of gentisic acid [16 (link)] to assess its effects on the radiolytic stability as radical scavenger.

Single bed position image acquisition centred on the tumour was performed with GE Discovery 690 or 710 PET-CT Scanners (GE Healthcare) for 10 min at 2 and 4 h following the administration of 18F-Fluoromisonidazole (FMISO) (manufactured by University of Cambridge) with an activity of 370 MBq. Precursor (1-(2′-Nitro-1′-imidazolyl)-2-O-tetrahydropyranyl-3-O-toluenesulfonyl-propanediol, NITTP) was used from Advanced Biochemical Compounds (ABX) and the synthesis of FMISO was performed on a FASTlab synthesis module (GE Healthcare) according to the manufacturer’s instructions. The product was then sterilized by filtration through a Millex-GV 0.22 µm sterile filter (Merck Millipore)^{35 (link)}.
The same scanner was used for the two visits of each patient with baseline scans and pre-surgery scans for atovaquone-treated and untreated patients. CT images provided attenuation correction and localization. All PET images were reconstructed with a Bayesian penalised-likelihood algorithm, Q.Clear (GE Healthcare) using a beta value of 400^{36 (link)}. As with previous work, respiratory motion correction was not performed for the presented analysis^{38 (link)}. Patients in cohort 1 had a median length of 13.5 (IQR 10.75–14) days between imaging timepoints, depending on their planned date for surgery. Patients in cohort 2 had a median length of 14 (IQR 7–14) days between imaging timepoints.