Cassette-Based Automated Production of 2-Deoxy-2-[18f]fluorocellobiose on the Trasis AllInOne with Undetectable [18F]FDG Contamination

The global rise in the incidence and severity of invasive fungal infections, particularly among immunocompromised and immunodeficient patients, has created an urgent need for rapid and accurate diagnostic techniques. Therefore, fungal-specific positron emission tomography imaging agents are increasingly in demand, as they offer the potential for early-stage detection of fungal infections. Recently, 2-deoxy-2-[18F]fluorocellobiose ([18F]FCB), a fluorine-18-labeled analog of cellobiose that is selectively metabolized by fungal pathogens possessing cellulose-degrading mechanisms (cellulolytic), was developed for the targeted imaging of Aspergillus infections. However, the final [18F]FCB contained less than 2% unreacted 2-deoxy-2-[18F]fluoroglucose ([18F]FDG), which can potentially interfere with image interpretation. Accordingly, this study aims to eliminate residual [18F]FDG from the final product by enzymatically converting it to [18F]FDG-6-phosphate through hexokinase-mediated phosphorylation. A Trasis AllInOne (Trasis AIO) module was used to automate the radiolabeling procedure. The reagent vials contain [18F]FDG, glucose-1-phosphate, cellobiose phosphorylase, adenosine triphosphate (ATP), and hexokinase. A Sep-Pak cartridge was used to purify the tracer. The overall radiochemical yield was 45–50% (n = 3, decay-corrected) in a 40 min synthesis time, with a radiochemical purity of >99% (no detectable [18F]FDG). This is a highly reliable protocol to produce current good manufacturing practice (cGMP)-compliant [18F]FCB for clinical PET imaging.