18F is the most commonly used radionuclide for PET imaging. Its half-life of approximately 2 h is suited for sameday imaging of many compounds that clear quickly from the body to allow visualization of uptake in the intended target. Traditionally, 18F has been attached to a carbon atom on a targeting molecule, but this has been a significant challenge, requiring complex and time-consuming chemistry.   There has been some progress in speeding up and simplifying radiofluorination on carbon through the use of automation.  Alternative labeling methods using silicon- or boron-based compounds are more efficiently labeled, but these agents typically tend to be hydrophobic, which could impact the biodistribution of many hydrophilic compounds of interest. Because fluorine binds to aluminum, we developed a procedure where the Al18F complex could be captured by a chelate, thereby greatly simplifying how imaging agents can be fluorinated for PET imaging. 18F- is mixed with Al3+ and the targeting agent bearing a ligand. The mixture is heated for 15 min and then filtered through an alumina cartridge to remove unreacted 18F-. If the targeting molecule is heat-sensitive, the ligand can be labeled with Al18F first and then attached to the targeting molecule at a lower temperature. The hydrophilic ligands can be attached to a wide variety of targeting agents without loss of affinity for the target. This presentation reviews our experience with this technology. The topics will include: the types of targeting molecules labeled to-date, factors that affect the labeling yields, the ligands used to bind Al18F, and in vivo residualization of Al18F complexes. This simple, efficient labeling procedure is highly adaptable and useful for 18F-tagging of a variety of compounds for molecular imaging.

Radiofluorination using aluminum-fluoride (Al<sup>18</sup>F)

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Radiofluorination using aluminum-fluoride (Al18F)

Radiofluorination using aluminum-fluoride (Al¹⁸F)