In the clinical management of Alzheimer’s disease (AD), amyloid PET and tau PET have become increasingly important as non-invasive imaging biomarkers capable of visualizing core AD pathological features in vivo. With the advent of anti-amyloid 𝛽 monoclonal antibodies such as lecanemab and donanemab, amyloid PET now plays a pivotal role in determining treatment eligibility and monitoring therapeutic response. Tau PET, which reflects the extent and progression of neurofibrillary tangle pathology, provides complementary information regarding disease staging and prognosis. These imaging modalities, aligned with the ATN classification framework, support more accurate diagnosis and individualized treatment planning. Furthermore, recent technological advances―including high-resolution, dedicated brain PET scanners and artificial intelligence (AI)-based image analysis―have significantly improved diagnostic precision and clinical applicability. These developments not only facilitate the detection of early pathological changes but also enhance reproducibility and scalability in both research and routine practice. As disease-modifying therapies continue to emerge, the integration of amyloid and tau PET imaging is expected to be central to the early diagnosis, patient stratification, and personalized therapeutic interventions for AD. This review highlights the evolving clinical roles of amyloid and tau PET in the new era of targeted AD treatment.

Theranostics is an emerging concept that integrates therapeutics and diagnostics. It can be implemented by switching the radionuclide of the same compound from one used for diagnostic imaging to one used for radioligand therapy. In diagnostic imaging, for example, not only can the expression levels of target molecules in metastatic lesions throughout the body be quantitatively assessed, but the effectiveness of treatment can also be predicted. In particular, in drug development, it is possible to optimize therapeutic agents based on the biodistribution of diagnostic compounds, thereby reducing physiological accumulation in normal organs and minimizing side effects. For treatment, RI-labeled ligands are delivered to target sites in the same way as diagnostic agents and can treat cancer from within the body using short-range radiation such as alpha or beta particles. In Japan, we are at the forefront of drug development and clinical applications using astatine-211 (¹¹At), which can be produced by cyclotrons, and further advances are anticipated.

Transplantation of stem cells has been developed as a promising strategy for the treatment of ischemic heart disease. In parallel, several strategies for the noninvasive visualization of transplanted stem cells have been developed, as understanding the cell dynamics after transplantation is important for stem cell therapy. In this paper, I would like to introduce the recent publication relating to the cell sheet tracking technique using SPECT with human sodium/iodide symporter as a reporter gene.

Recent advancements in artificial intelligence (AI), particularly deep learning, have led to significant progress in both diagnostic and therapeutic applications in nuclear medicine, including image quality enhancement, diagnostic support, dose calculation, and treatment response prediction. Image processing techniques using convolutional neural networks and generative adversarial networks have contributed to reduced radiation exposure and shortened acquisition times, while tumor segmentation-based approaches are expected to improve the efficiency of personalized medicine. However, challenges remain, such as the scarcity of annotated nuclear medicine image datasets, variations in imaging protocols across institutions, and the necessity of incorporating explainable AI to ensure transparency and interpretability. This article outlines recent advances in AI technologies in the field of nuclear medicine, discusses their clinical applicability, and addresses current challenges and future perspectives.

This article provides an overview of the current state of nuclear medicine in Germany, one of the leading countries in this field in Europe, with a particular focus on the clinical framework of the Department of Nuclear Medicine at the University of Wuerzburg. In the diagnostic domain, the clinical application of molecular imaging, especially positron emission tomography (PET), is introduced, while in the therapeutic domain, the current status and future perspectives of targeted radionuclide therapy (TRT) directed at prostate-specific membrane antigen (PSMA) are discussed. Furthermore, recent years have seen growing interest from pharmaceutical and biotech companies in the nuclear medicine field, leading to accelerated mergers, acquisitions, and collaborations involving radiopharmaceutical companies. Additionally, Germany’s 2024 amendment to its Medical Research Act has improved the environment for conducting clinical research, establishing a regulatory framework that facilitates the clinical application of new radiopharmaceuticals. This article discusses these industrial trends and regulatory changes, along with the current status and future challenges of nuclear medicine as a fusion of diagnostics and therapy.