Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 0 0 2026 02 16 1589 1589 Hossein Arabi Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211, Geneva 4, Switzerland Swagat Dash Department of Nuclear Medicine & Molecular Theranostics, Sarvodaya Hospital, Faridabad, India Habibollah Dadgar Department of Nuclear Medicine and Molecular imaging, Cancer Research Center, RAZAVI Hospital, Mashhad University of Medical Science, Mashhad, Iran Majid Assadi The Persian Gulf Nuclear Medicine Research Center, The Persian Gulf Biomedical Research Institute, Department of Nuclear Medicine, Molecular Imaging, and Theranostics, Bushehr Medical University Hospital, School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran 2026 02 14 Theranostics has revolutionized nuclear medicine by integrating diagnostic imaging and targeted radionuclide therapy, delivering precision oncology with proven survival benefits in cancers such as prostate cancer and neuroendocrine tumors. However, inter-patient variability in biodistribution, response, and toxicity remains a major challenge. This editorial explores the transformative potential of digital twins, dynamic virtual replicas of patients continuously updated with real-world data, as a natural synergy for theranostics. Theranostic digital twins enable predictive dosimetry, personalized treatment optimization, responder identification, and toxicity forecasting through hybrid AI-mechanistic models grounded in radiopharmacokinetics and radiobiology. Early development should prioritize clinically meaningful applications supported by comprehensive, harmonized multimodal datasets, robust hybrid modeling, and effective synchronization mechanisms. Large-scale collaboration and systematic evidence synthesis are essential to accelerate clinical translation. By bridging in-silico simulation with real-world theranostics, digital twins promise to evolve nuclear medicine toward truly proactive, equitable, and predictive personalized care. https://fbt.tums.ac.ir/index.php/fbt/article/view/1589 https://fbt.tums.ac.ir/index.php/fbt/article/download/1589/554