Recent studies with a combined PET/CT scanner

Background. Coregistration of anatomical (CT) and functional (PET) images for whole-body oncology is complicated by differences in patient positioning, displacement of abdominal organs, and respiration. Methods. A combined PET/CT tomograph with the unique capability to acquire coregistered functional and anatomical images has been designed and built. The PET/CT scanner comprises a Siemens Somatom AR.SP spiral CT and a partial ring, rotating ECAT ART PET scanner. The CT images are used to correct the PET data for scatter and attenuation. Fully quantitative whole-body images are, therefore, obtained for an axial extent of 100 cm in an imaging time of less than 1 h. Results. Over 70 patients have been imaged on the combined scanner. A range of different cancers have been studied, including lung, esophageal, head and neck, melanoma, lymphoma, pancreas and renal cell. The aligned PET and CT images an used both for diagnosis and staging of disease and for evaluating response to therapy. Conclusion. A combined PET and CT scanner is a practical and effective approach to acquiring coregistered anatomical and functional images in a single scanning session. This approach potentially offers improvements in diagnosis and staging of disease, monitoring of therapy, biopsy sampling procedures, and radiation therapy treatment planning.