A compound comprising a
prostate specific
membrane antigen (PSMA)-targeting
moiety of the following formula (I) or of a salt or a solvate thereof. R1 is —R1aR1b— wherein R1a is absent, —CH2—, —O—, or —S—, and R1b is —CH2— or —CHF—. R2 is —(CH2)3—O—, —(CH2)3—, —(CH2)4—, —CH2—O—(CH2)2—, or —CH2—S—(CH2)2. R3 is
ethylene fused to a
tricyclic fused ring. L1, L2, L3, L4, L5b L5c, L6 and L7 are linkages (e.g.
peptide bonds). Xbr is a branching atom. Rrad is a radiometal chelator. Ralb is an
albumin binder. n1, n2, n3, n4, and n5 are integers. When the PSMA-targeting
moiety is linked to a radiolabeling group, the compound may be used as an
imaging agent or therapeutic agent for PSMA-expressing diseases / conditions.