Expanding the Theranostic Toolbox: Emerging Therapeutic Isotopes.

Radiopharmaceutical therapy and theranostics have rapidly evolved as transformative strategies in nuclear medicine, enabling targeted delivery of therapeutic radiation to malignant tissues while sparing normal organs. In parallel, recent advances in radionuclide production-including accelerator-based methods, photonuclear techniques, and generator systems-have improved the clinical availability of isotopes for established and emerging radiopharmaceuticals. This review provides an overview of emerging therapeutic isotopes in radiopharmaceutical therapy, highlighting their physical properties, mechanisms of action, and clinical potential. Although emphasizing α-emitters, β-emitters, and Auger emitters, this review also explores routes of production, supply chain challenges, and the influence of decay radiation characteristics on therapeutic suitability for different tumor types.