In-target produced [11C]methane: Increased specific radioactivity

Specific Activity of 11C-Labelled Radiotracers: A Big Challenge for PET Chemists

“…Although different sources have been encountered and their individual contribution somehow quantified, it seems clear that the final specific activity of 11 C-labelled radiotracers is extremely dependent of site-specific configuration and minimal alteration of experimental conditions can lead to considerable effects on specific activity values, especially when such specific activities are high. Tables 5 and 6 show specific activity values reported in the literature for syntheses of 11 Clabelled radiotracers synthesized either from cyclotron generated (Andersson et al, 2009)). In this case, the authors attributed this finding to [ 11 C]CO 2 being more sensitive to isotopic dilution from CO 2 in the air, than what the influence of environmental contamination of CH 4 is likely to have on the specific activity.…”

Development of additive [ 11 C]CO 2 target system in the KOTRON-13 cyclotron and its application for [ 11 C]radiopharmaceutical production

“…Finally, the [ 11 C]CO 2 obtained from the tailor-made C-11 target system was applied for the production of various carbon-11 labeled radiopharmaceuticals, such as [ 11 carbon, as previously reported [12,13]. After the labeling was performed under the desired reaction conditions, the mixture was purified by solid-phase extraction or High Performance Liquid Chromatography (HPLC) system.…”

Synthesis of ([11C]carbonyl)raclopride and a comparison with ([11C]methyl)raclopride in a monkey PET study

“…([ 11 C]Methyl)raclopride was prepared by O-methylation of des-methyl raclopride precursor using [ 11 C]methyl triflate obtained from the in-target produced [ 11 C ]methane [22]. More details of the procedure for the synthesis of ([ 11 C]methyl)raclopride can be found elsewhere [14].…”

“…the synthesis of ([ 11 C]methyl)raclopride was produced by gas phase iodination [21] of intarget produced [ 11 C]methane followed by reacting with silver triflate using a methyl iodide system supplied by Scansys Laboratorieteknik APS (Copenhagen, Denmark). The procedure for in-target production of [ 11 C]methane was published previously [22]. High performance liquid chromatography (HPLC) was performed using a Hitachi L-6200 gradient pump and a (1 mL) into a sterile vial containing 10 mL of sterile PBS (pH 7.5).…”