Computed Tomography in Comprehensive Oncologic Evaluation: Integration with Molecular PET Imaging

Computed tomography (CT) and positron emission tomography (PET) are pivotal imaging modalities in oncology, each offering unique advantages. CT provides high-resolution anatomical details, enabling precise tumor localization, characterization, and TNM staging. However, its reliance on structural data limits its ability to assess metabolic activity. Conversely, PET, particularly with [F]-FDG, captures functional and molecular processes, revealing tumor viability and heterogeneity. The integration of these modalities in hybrid PET/CT systems has revolutionized oncologic care by combining anatomic precision with metabolic sensitivity, improving diagnostic accuracy, staging, and therapeutic planning. This chapter explores the technical principles of CT and PET, highlighting advancements such as multidetector CT, dual-energy CT, and photon-counting CT, alongside emerging PET radiopharmaceuticals. It underscores the clinical impact of PET/CT in detecting occult metastases, assessing early treatment response, and differentiating recurrence from post-therapeutic changes. Key applications include guiding radiotherapy planning, where metabolic tumor volume (MTV) delineation enhances precision and reduces toxicity. Limitations, such as false positives from inflammatory FDG uptake or CT’s inability to discriminate viable tissue, are also discussed. Ultimately, PET/CT exemplifies precision medicine, enabling tailored oncologic management. Its role in optimizing staging, prognostication, and therapy monitoring underscores its indispensability in modern oncology. Future directions, including novel tracers and AI-driven analysis, promise further advancements in cancer imaging and patient outcomes.