The radiolabeling of proteins by the [18F]AlF method

A new ([(18)F]AlF)(2+)-binding ligand that contains 1,4,7-triazacyclononane-1,4-diacetate (NODA) attached to a methyl phenylacetic acid group (MPA) was conjugated to N-(2-aminoethyl)maleimide (EM) to form NODA-MPAEM. The NODA-MPAEM was labeled with ([(18)F]AlF)(2+) at 105°C in 49-82% yield and conjugated at room temperature to an antibody Fab' fragment in 69-80% yield (total time ∼50min) and with retention of immunoreactivity. These data indicate that the rapid and simple [(18)F]AlF-labeling method can be easily adapted for preparing heat-sensitive compounds with (18)F quickly and in high yields.