• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.261-268
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• 2023

[¹⁸F]Fluorocholine is a radiopharmaceutical used non-invasively in positron emission tomography to diagnose parathyroid adenoma, prostate cancer, and hepatocellular carcinoma by evaluating the choline metabolism. In this study, a radiolabeling method for [¹⁸F]fluorocholine was optimized using a solid phase extraction (SPE) cartridge. [¹⁸F]Fluorocholine was labeled in two steps using an automated synthesizer. In the first step, dibromomethane was reacted with [¹⁸F]KF/K2.2.2/K₂CO₃ to obtain the intermediate [¹⁸F]fluorobromomethane. In the second step, [¹⁸F]fluorobromomethane was passed through a Sep-Pak^Ⓡ Silica SPE cartridge to remove the impurities and then reacted with N,N-dimethylaminoethanol (DMAE) in a Sep-Pak^Ⓡ C18 SPE cartridge to label [¹⁸F]fluorocholine. The reaction conditions of [¹⁸F]fluorocholine were optimized. The synthesis yield was confirmed according to the number of silica cartridges and DMAE concentration. No statistically significant difference in the synthesis yield of [¹⁸F]fluorocholine was observed when using four or three silica cartridges (P>0.05). The labeling yield was 11.5±0.5% (N=4) when DMAE was used as its original solution. On the other hand, when diluted to 10% with dimethyl sulfoxide, the radiochemical yield increased significantly to 30.1±5.2% (N=20). In conclusion, [¹⁸F]Fluorocholine for clinical use can be synthesized stably in high yield by applying an optimized synthesis method.

• The Korean Journal of Nuclear Medicine
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• v.35 no.3
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• pp.185-191
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• 2001

Objectives: Recently, $[methyl-^{11}C]-({\beta}$-Hydroxyethyl)trimethylammonium ($[^{11}C]$choline) Has been discovered to be a very effective tracer in imaging various human tumors using positron omission 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 $[^{11}C]$choline. This can be supplemented by the substitution of $[^{11}C]$choline with $[methyl-^{18}F]$fluorocholine. Here, we would like to report ceil uptake and biodistribution of $[^{11}C]$choline and $[^{18}F]$fluorocholine as a basic study. Methods: $[^{11}C]$Choline was prepared by the treatment of $[^{11}C]CH_3I$ with N,N-dimethylaminoethanol and $[^{18}F]$fluorocholine was synthesized from reaction of $CH_2Br[^{18}F]F$ with N,N-dimethylaminoethanol. The radiochemical purity was checked by high performance liquid chromatography (HPLC). The blodistribution of $[^{11}C]$choline and $[^{18}F]$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). Results: 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 $[^{11}C]$choline and 13%ID/g for $[^{18}F]$fluorocholine. In the kidney, radioactivity decreased over time; the uptake was 15%ID/g for $[^{11}C]$choline and 20%ID/g for $[^{18}F]$fluorocholine, 80 min post-injection. The cell uptake of $[^{11}C]$choline was 4.93% for glioma (9L) and 18.69% for colon adenocarcinoma (SW620). For $[^{18}F]$fluorocholine, 1.77% for glioma (9L) and 2.77% for colon adenocarcinoma (SW620). Conclusion: $[^{11}C]$Choline and $[^{18}F]$fluorocholine showed a different cell uptake tendency, depending on cancer cell line.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.506-510
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• 2004

There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.