FAP and neoplasm: Therefore, we aimed to image tumour heterogeneity in a limited cohort of mCRPC patients as part of the eligibility assessment for [177Lu]Lu-PSMA-617 RLT using [68Ga]Ga-/[18F]F-PSMA-11/1007 to assess PSMA expression, 2-[18F]FDG for glucose uptake and [68Ga]Ga-FAPI-46 for FAP expression, and to identify potential descriptive imaging phenotypes to support therapeutic decision making.