RPRD | Simultaneous Synthesis of Two Different 11C-Labeled Compounds Using O…

Jae Hyung Lee, Yong-Hyun Cho, Yong-Seok Lee, Yun-Sang Lee, Young Chul Lee¹, Hong-Jae Lee, Hyun-Ju Kim, Dong Soo Lee, and Jae Min Jeong *

Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea

¹Department of Biomedical Engineering, Seoul National University Hospital, Seoul, Korea

Purpose

As needs for positron emission tomography (PET) scan using 11C labeled compounds increased, multiple production of the 11C labeled compounds in a day is common in a cyclotron lab.  After one production  of  the  11C labeled  compound,  next  production should be delayed at least for 3 or 4 hr because of radiation safety. Here, we developed a method for simultaneous synthesis of two different 11C labeled compounds using one synthesis module and high performance liquid chromatography (HPLC) injection loops, and evaluated the feasibility of this method.

Materials and Methods

[11C]CO2 was produced by a PETtrace cyclotron and converted to [11C]CH4 and then to [11C]CH3I in a 11C module, TRACERlab FX C Pro. The [11C]CH3I gas was delivered continuously to serially connected HPLC injection loops. Each HPLC loop contained 1 mg of N-Methyl-2-(2-amino-4-cyanophenylthio)benzylamine in DMSO for [11C]DASB or 0.5 mg of L-homocysteine thiolactone hydrochloride in DMF for [11C]MET. After 5 min, the reaction mixture was purified with each HPLC system.

Results

[11C]DASB and [11C]MET were simultaneously synthesized 7 times by one 11C module with two HPLC loops, and the obtained product activity of [11C]DASB was 3.60 ± 0.88 GBq(1st loop) and that of [11C]MET was 4.60 ± 1.80 GBq(2nd loop) without decay correction. The specific activity of [11C]DASB was 19.9 ± 7.20 GBq/mole (n=7).

Conclusion

We developed simultaneous synthesis method of two different 11C labeled compounds using one synthesis module and one irradiation of a cyclotron. This method would be helpful for efficient use of cyclotron and 11C synthesis module.