Recent Advances in Preclinical Studies of the Theranostic Agent [⁶⁴Cu]CuCl₂

⁶⁴Cu is gaining recognition not only for its diagnostic capabilities in nuclear medical imaging but also for its therapeutic and theranostic potential. The simultaneous β- and Auger emissions of ⁶⁴Cu can be utilized to induce a therapeutic effect on cancerous lesions. The finding of the exceptional biodistribution characteristics of the radionuclide ⁶⁴Cu, when administered as basic copper ions, has highlighted its potential therapeutic application in cancer treatment. Preclinical and clinical research on the effectiveness of [⁶⁴Cu]CuCl₂ as a theranostic radiopharmaceutical has commenced only in the past decade. Current clinical studies are increasingly demonstrating the high specificity and uptake of [⁶⁴Cu]Cu²⁺ by malignant tissues during early cancer progression, indicating its potential for early cancer diagnosis across various organs. This short review aims to present the latest preclinical studies involving [⁶⁴Cu]CuCl₂, offering valuable insights for researchers planning new in vitro and in vivo studies to explore the theranostic potential of [⁶⁴Cu]Cu²⁺.