To evaluate in vivo kinetics of DUNP19 in healthy organs and LRRC15-expressing tumors, sequential PET images were acquired of subcutaneous (s.c.)osteosarcoma (SAOS2) bearing mice after intravenous (i.v.)administration of a 64Cu-labeled version of the mAb ([64Cu]Cu-DUNP19). Here, LRRC15 is linked to osteosarcoma.