Ex vivo biodistribution of 99mTc-J591Cdia in mice with subcutaneous DU145 or DU145-PSMA tumours p.i. (a) DU145-PSMA tumour. (b) DU145 tumour. As for the imaging studies, mice (n = 4) with established tumours received 10 to 13 μg (between 25 and 35 MBq/injection) of 99mTc-J591Cdia by tail vein injection. Tracer uptake in selected organs at 8 h p.i., as measured by gamma counting, is expressed as mean percent injected dose/gram.