MAPT and supranuclear palsy, progressive, 1: While first-generation tau tracers suffered from substantial off-target binding, the next generation tau tracer [18F]PI-2620 proved absent off-target binding to monoamine oxidases, high affinity to 3R/4R tau in AD and also revealed binding in the 4R tauopathies PSP (Brendel et al., 2020, Franzmeier et al., 2022) and CBS (Franzmeier et al., 2022, Palleis et al., 2021).