PET/CT and Hypo-Fractionated Radiotherapy of Patients with Head and Neck Cancer

Positron emission tomography/Computer tomography (PET/CT) is a multimodality imaging diagnostic technique that analyzes the uptake and retention of different radiopharmaceuticals by cells providing metabolic information on biochemical processes. PET/CT has been used for radiotherapy planning, providing useful information to the Radio-oncologist about the localization, size and metabolic activity of tumor lesions. In this paper, we show advantages of the 18F-FDG PET/CT respect to simple CT imaging for target volume delineation in patients with diagnosis of Squamous Head and Neck Carcinoma that has been scheduled to undergo a hypofractionated radiotherapy treatment. On ten studied patients, the target volume defined from PET/CT images was less extensive than those defined from simple CT images. In six patients the target volume was significantly less extensive and in two of them a new lymph node disease was reported, re-staging and corresponding target volume was also delineated with less extensive margins from PET/CT images. A greater accuracy in delineating the volumes and improving the distribution of doses in the planning of the radiant treatment in these patients was possible, allowing a high precision in the delivery of the prescribed dose to the target volume diminishing the maximum dose to the adjacent healthy tissues. In conclusion we show that the use of 18F-FDG PET/CT was superior than the simple CT as the primary modality of imaging for hypofractioned radiotherapy treatment planning in patients with Squamous Head and Neck Carcinoma.