Unlike FTP, 18F-MK-6240 rarely exhibits off-target binding in the basal ganglia and choroid plexus, but it does exhibit tracer retention in neuromelanin- and melanin-containing cells and meninges [22, 23]. 3H-MK-6240 demonstrated negligible binding to tau aggregates in CTE cases at stages II/III to IV in an autoradiography study across multiple tauopathies [24, 29]. This evidence concerns the gene MAPT and tauopathy.