Positron Emission Tomography/Computed Tomography (PET/CT)-guided radiation therapy simulation has transformed cancer treatment, ushering in enhanced precision and individualization. This discussion delves into clinical indications, applications, procedures, and limitations, providing a comprehensive overview across cancer types. 
 Clinical indications underscore PET/CT's role in accurate staging, target volume delineation, treatment response assessment, and post-treatment recurrence detection. Accurate staging is crucial for tailored treatment plans, while target volume delineation benefits from PET's identification of metabolic patterns. Ongoing treatment response assessment enables dynamic adjustments, and post-treatment, PET/CT aids in detecting recurrent disease. 
 Applications highlight PET/CT's treatment planning optimization by combining anatomical and functional information. Fusion of PET
 and CT images customizes radiation plans, identifying active regions for targeted delivery while sparing healthy tissues. This fusion facilitates tailored strategies, minimizing radiation exposure and enabling dynamic adaptations. 
 Procedural aspects detail imaging acquisition, image fusion, target delineation, treatment planning, and ongoing monitoring. Starting with radiotracer administration, typically fluorodeoxyglucose (FDG), PET/CT captures functional and anatomical data. Image fusion aids in target delineation and optimizing plans. Ongoing monitoring allows real-time adjustments. 
 Specific clinical applications across cancers demonstrate PET/CT's versatility. In head and neck cancers, it ensures precise delineation while avoiding critical structures. In lung cancer, it improves tumor extent identification. Similar advantages apply to lymphomas, sarcomas, brain tumors, metastatic disease, and esophageal, gastrointestinal, breast, prostate, gynecological, and pediatric cancers. 
 Limitations include spatial resolution challenges, false positives, cumulative radiation exposure, lesion size, histology, and standardization issues. Ongoing research targets spatial resolution enhancement, radiomics and AI integration, novel tracers, hybrid imaging, patient-specific dosimetry, clinical trials, multimodal workflows, cost-effectiveness, accessibility, and education. 
 PET/CT-guided radiation therapy simulation is transformative. Ongoing advancements promise a more precise and individualized approach, enhancing patient outcomes in cancer management.
Read full abstract