Influence of FDG/PET CT image registration and fusion on the anal canal carcinoma target volume delineation

The best option for treatment of anal cancer is chemoirradiation. FDG-PET detects the primary tumor and metastatic involved lymph nodes better and more frequently than CT only. During last decade, fusion of different imaging modalities became important factor in radiotherapy treatment planning. Patient was diagnosed for squamous cell carcinoma by colonoscopy and FDG/PET followed by histopathological confirmation. A precise determination of target volume is very important in radiotherapy. In recent years higher utilization of FDG-PET CT fusion in radiotherapy treatment planning of anal cancer is recorded. Image registration and fusion between CT for radiotherapy treatment planning and FDG PET can help better visualization and especially in the determination of boost target volume. We observed much better detection of affected lymphatics by the data obtained by image co-registration of PET and CT data. This fact allowed us to increase dose prescribed to tumor and affected lymph nodes. PET is very important imaging modality for patients with anal canal cancer. FDG-PET has proved to be important tool for the radiotherapy treatment planning of anal canal carcinoma