PSMA-targeted radiotherapy of prostate cancer (PCa) has emerged recently as a promising approach to the treatment of disseminated disease. A small number of ligands have been evaluated in patients, and while early tumor response is encouraging, relapse rate is high, and these compounds localize to the parotid, salivary and lacrimal glands as well as the kidney, leading to dose-limiting toxicities and adverse events affecting quality of life.