Patients were injected with 100 MBq of 18F-fluorocholine

The incorporation of [18F]FDG and [18F]FCH (Fluorocholine) was determined through the uptake of the radiotracer into the trichloroacetic acid-insoluble cellular fraction of tumor cell lines. Briefly, cells were seeded in 96-well plates at 10,000 cells per well. After 30 min of incubation with 500 μCi/ml of [18F]FDG or [18F]FCH, cells were washed twice in icecold PBS and precipitated with ice-cold 5% trichloroacetic acid. Then, cells were washed once with ice-cold 95% ethanol and solubilized with 1N NaOH. An aliquot was neutralized, and the radioactivity was determined in a liquid scintillation counter. All experiments were performed in triplicate. A measurable uptake of [18F]FCH and [18F]FDG was observed in the five tumor cell lines. The incorporation of both tracers increased from 10 to 60 min.