FOLH1 and neoplasm: For all animals, significant concentrations of 99mTc radioactivity (2–5 %ID g−1) were measured in PSMA-expressing tumours 2 h post-injection, and although 99mTc tumour concentrations were consistently higher for animals administered [99mTcO2(DPAn-PSMAt)2]+, there were no statistically significant differences between [99mTcO2(DPAn-PSMAt)2]+ and [99mTcO2(DPMEP-PSMAt)2]+ in either mouse model.