Imaging and Therapy Against Hypoxic Tumors with 64Cu-ATSM

Hypoxia in tumors is known to contribute to the malignant characteristics such as therapy resistance and metastatic potential. Cu-diacetyl-bis (N4-methylthiosemicarbazone) (Cu-ATSM), labeled with several Cu radioisotopes (60Cu, 62Cu and 64Cu) is a potential PET imaging agent that targets tumor hypoxia with over-reduced conditions. Clinical studies of Cu-ATSM PET has been conducted worldwide in recent years and the usefulness of this agent is being recognized. Multicenter clinical study of 62Cu-ATSM PET has been conducted in Japan. Among Cu-ATSM tracers, 64Cu-ATSM can be used not only as a PET imaging agent but also as a therapeutic agent, because 64Cu emits β− particle and Auger electron, which can damage the cells. Here, we will discuss the present status and future prospects of Cu-ATSM.