FAP and cancer: Small-scale phase 1 studies with [177Lu]Lu-FAPI-04, [177Lu]Lu-FAPI-46, [177Lu]Lu-FAP-2286 and [90Y]Y-FAPI-46 demonstrated reasonably low absorbed doses to healthy organs at risk with relatively high uptake in cancer tissue for a wide range of administered activities per cycle: 1.85 - 4.44 GBq [177Lu]Lu-FAPI-46 vs. 6 GBq [90Y]Y-FAPI-46 vs. 5.8 ± 2.0 GBq [177Lu]Lu-FAP-2286 94-96.