A quartz-lined carbon-11 target: striving for increased yield and specific activity.
BACKGROUND
The increased demand for high specific radioactivity neuroreceptor ligands for positron emission tomography (PET) requires the production of high specific radioactivity carbon-11 in high yields. We have attempted to address this issue with the development of a new quartz-lined aluminium target for the production of [(11)C]methane or [(11)C]carbon dioxide.


METHODS
The new target has been tested with respect to yields of [(11)C]methane and [(11)C]carbon dioxide, and the effect of the quartz liner has been evaluated. The specific radioactivities of a large number of radiopharmaceuticals produced using this target have also been measured.


RESULTS
The described target produces [(11)C]-labelled gases in excellent yields, and losses of radioactivity in the target on production of [(11)C]methane have been reduced significantly by the use of a quartz liner. Radiopharmaceuticals with specific radioactivities up to 9000 GBq/μmol at end of bombardment (EOB) (243 Ci/μmol) have been produced using this target.


CONCLUSIONS
We have developed a reliable, high-yielding carbon-11 gas target which is now routinely used in our department for the production of high specific activity radiopharmaceuticals.
Cyclotron and Radiochemistry Unit, Herlev University Hospital, Copenhagen, Denmark.
Jacek
J
Koziorowski
Peter
P
Larsen
Nic
N
Gillings
D000535:Aluminum / Q000737:chemistry; D002245:Carbon Dioxide / Q000138:chemical synthesis / Q000737:chemistry; D002250:Carbon Radioisotopes; D008697:Methane / Q000138:chemical synthesis / Q000737:chemistry; D049268:Positron-Emission Tomography; D011791:Quartz; D011854:Radiochemistry / Q000295:instrumentation*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000737:chemistry*
D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D002245:Carbon Dioxide; D011791:Quartz; D000535:Aluminum; D008697:Methane