Highly efficient automated synthesis of [11C]choline for multi dose utilization

[C-11]Choline has been under investigation as a PET ligand for imaging tumor tissue, especially prostate cancer. An improved, automated synthesis of the tracer now was established. [C-11] Choline was produced by labeling 2(dimethylamino)-ethanol (DMAE) with [C-11]CH,I in a Tefzel(R) tube at room temperature without solvent. The product was purified using a cation exchange cartridge. Reaction conditions were optimized with respect to synthesis time and amount of DMAE, resulting in radiochemical yields higher than 80% using 60 mul of DMAE in 20 min, radiochemical purity was > 99% and residual DMAE was below 10ppm. After C-11-productioD of 1 h at 50 pA [C-11]choline activities of 30.0 +/- 5.6 GBq (n = 29) were obtained in sterile solution ready for intravenous administration. (C) 2004 Elsevier Ltd. All rights reserved.