Intratumoral Distribution of [177Lu]Lu-PSMA-617 Over Time and in Relation to Diagnostic Tracers in Animal Models of Prostate Cancer

Introduction: Prostate-specific membrane antigen (PSMA) is a target for diagnostic positron emission tomography (PET)-tracers and radiopharmaceutical therapy (RPT), for example, [177Lu]Lu-PSMA-617, in prostate cancer. This autoradiography study investigates [177Lu]Lu-PSMA-617 intratumoral distribution over time, compared with PSMA expression, proliferation (Ki67), and [68Ga]Ga-PSMA-11, [18F]F-PSMA-1007, [18F]-fluorodeoxyglucose, and [18F]-fluorocholine distribution. Mice with LNCaP, 22Rv1, or PC-3 PIP xenografts got [177Lu]Lu-PSMA-617 i.v. Sacrificed 1 h p.i. if coinjected with diagnostic tracers, otherwise at 20 min, 1–2, 12, 24, 48, 72 h, or 2–3 weeks p.i. Cryosectioned tumors imaged by autoradiography, adjacent sections Ki67 or PSMA stained.