The present invention is a compound represented by the following formula (1) or a salt thereof. Furthermore, the present invention is an imaging agent used for imaging a tau protein, the imaging agent containing a compound represented by the formula (1) below or a salt thereof. In the formula (1), R
3
is a radioactive iodine.
本发明是由以下式(1)表示的化合物或其盐。此外,本发明是用于成像tau蛋白的成像剂,该成像剂含有以下式(1)表示的化合物或其盐。在式(1)中,R3是放射性
碘。