Positron emission tomography (PET)–based multimodal imaging, including PET/computed tomography (PET/CT) and PET/magnetic resonance (PET/MR), plays an increasingly important role in precision radiotherapy by integrating metabolic and anatomical information. This review summarizes the clinical applications of PET‐guided imaging in tumor staging, target volume delineation, and radiotherapy planning. PET/CT remains the primary modality in most oncological settings owing to its geometric accuracy, rapid acquisition, and broad clinical availability, whereas PET/MR provides superior soft‐tissue contrast and is particularly valuable in neuro‐oncological and pelvic tumors. Recent advances in tumor‐specific radiotracers, image reconstruction, and artificial intelligence–assisted analysis have further improved the accuracy and efficiency of PET‐guided radiotherapy. Despite these advantages, challenges such as limited spatial resolution, variability in quantitative parameters, and high implementation costs persist. Emerging technologies, including total‐body PET, advanced detector systems, and AI‐driven adaptive radiotherapy, are expected to address these limitations and facilitate clinical translation. Overall, PET‐based multimodal imaging represents a critical component of biologically guided and personalized radiotherapy, with substantial potential to improve treatment precision and patient outcomes.

A growing number of studies have demonstrated that the skeleton is an endocrine organ that is involved in glucose metabolism and plays a significant role in human glucose homeostasis. However, there is still a limited understanding of the in vivo glucose uptake and distribution across the human skeleton. To address this issue, we aimed to elucidate the detailed profile of glucose uptake across the skeleton using a total-body positron emission tomography (PET) scanner. A total of 41 healthy participants were recruited. Two of them received a 1-hour dynamic total-body ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET scan, and all of them received a 10-minute static total-body ¹⁸F-FDG PET scan. The net influx rate (K_i) and standardized uptake value normalized by lean body mass (SUL) were calculated as indicators of glucose uptake from the dynamic and static PET data, respectively. The results showed that the vertebrae, hip bone and skull had relatively high K_i and SUL values compared with metabolic organs such as the liver. Both the K_i and SUL were higher in the epiphyseal, metaphyseal and cortical regions of long bones. Moreover, trends associated with age and overweight with glucose uptake (SUL_max and SUL_mean) in bones were uncovered. Overall, these results indicate that the skeleton is a site with significant glucose uptake, and skeletal glucose uptake can be affected by age and dysregulated metabolism.