Role of PET-CT in cancers around the esophagus and the bronchus

Fluorodeoxyglucose-positron emission tomography (FDG-PET) is a useful modality for cancer diagnosis. It, however, often needs assistance from morphological imaging modalities such as CT or MRI for accurate diagnosis. PET-CT is a combination of a functional imaging tool. PET, and a morphological imaging tool, CT. The areas around the esophagus and bronchi contain complicated anatomical structures and display many variations of physiological uptake of FDG, which makes PET interpretation difficult. PET-CT solves this problem and allows easier and more confident interpretations. Though MRI may be superior to FDG-PET in diagnosis of primary cancer, FDG-PET is very useful in detecting unknown primary cancers which are negative on CT or MRI. In staging, it is possible to accurately localize nodal or other metastases, which has a bearing on surgical or radiation treatment planning. There are some issues in determining therapeutic efficacy, such as optimal timing of evaluation and avoiding false positive findings due to postradiation inflammation. Nonetheless, there is a report recommending evaluation using the change of standardized uptake value (SUV) of FDG uptake in the tumor. Radiation therapy planning using PET-CT has been tried in several institutes and new challenges using PET-CT are to be expected. (author)