María Jimena Salgueiro, Marcela Zubillaga
The convergence of nanotechnology with nuclear medicine has led to the development of theranostic nanoplatforms that combine targeted imaging and therapy within a single system. This review provides a critical and updated synthesis of the current state of nanoplatform-based theranostics, with a particular focus on their application in oncology. We explore multifunctional nanocarriers that integrate diagnostic radionuclides for SPECT/PET imaging with therapeutic radioisotopes (α-, β-, or Auger emitters), chemotherapeutics, and biological targeting ligands. We highlight advances in nanomaterial engineering—such as hybrid architectures, surface functionalization, and stimuli-responsive designs—that improve tumor targeting, biodistribution, and therapeutic outcomes. Emphasis is placed on translational challenges including pharmacokinetics, toxicity, regulatory pathways, and GMP-compliant manufacturing. The article closes with a forward-looking perspective on how theranostic nanoplatforms could reshape the future of personalized oncology through precision-targeted diagnostics and radiotherapy.