A study on the synthesis and its biodistribution of C-11 and F-18 labelled choline

Recently, (methyl-11C)-(β-Hydroxyethyl)trimethylammonium ([11C]choline) has been discovered to be a very effective tracer in imaging various human tumors using positron emission tomography. Because of the short half-life of C-11, it is very difficult to use in a routine imaging procedure and needs a frequent synthesis of (11C) choline. This can be supplemented by the substitution of (11C)choline with (methyl-18F) fluorocholine. Here, we would like to report cell uptake and biodistribution of (11C)choline and (18F) fluorocholine as a basic study. (11C)Choline was prepared by the treatment of (11C)CH3l with N,N-dimethylaminoethanol and (18F)fluorocholine was synthesized from reaction of CH2Br(18F) with N,N-dimethylaminoethanol. The radiochemical purity was checked by high performance liquid chromatography (HPLC). The biodistribution of (11C)choline and (18F)fluorocholine was determined in balb/c mouse at 5 min, 20 min, 40 min and 80 min. the cell uptake was measured using glioma (9L) and colon adenocarcinoma (SW620). The radiochemical purity was more than 98% after purification. In the liver, uptake did not change over time; the uptake was 20%ID/g for (11C)choline and 13%ID/g for (18F)fluorocholine. In the kidney, radioactivity decreased over time; the uptake was 15%ID/g for (11C)choline and 20%ID/g for (18F)fluorocholine, 80 min post-injection. The cell uptake of (11C)choline was 4.93% for glioma (9L) and 18.69% for colon adenocarcinoma (SW620). For (18F)fluorocholine, 1.77% for glioma (9L) and 2.77% for colon adenocarcinoma (SW620). (11C)Choline and (18F)fluorocholine showed a different cell uptake tendency, depending on cancer cell line