PET/CT fusion in radiotherapy treatment planning for head and neck cancer

e17046 Background: Positron emission tomography/computerized emission tomography (PET/CT) creates fusion images which are a combination of tissue function (PET) and anatomy (CT). It is playing an increasingly important role in radiotherapy of cancer. Aim of this report is to investigate the value of PET/CT fusion in radiotherapy treatment planning for head and neck cancer. Methods: 17 patients with head and neck cancer underwent 18 F-FDG PET/CT imaging. The primary lesions were all proved by pathology. PET/CT fusion images, PET images and CT images of the same patient were analyzed frame by frame. TNM stage was analyzed based on PET/CT and CT. PET/CT-GTV and CT-GTV volume were analyzed. Results: 59 malignant lesions were detected by PET/CT in the 17 patients. Among 59 lesions, 31 lesions were detected and displayed definitely by both PET and the plain scan of CT; 23 lesions were detected definitely by PET but not by the plain scan of CT; while 5 lesions were negative by PET but definitely by the plain scan of CT. The sensitivity of PET/CT was higher than PET and the plain scan of CT alone. Changes in TNM stage occurred in 7 patients (41%), based on PET/CT. The median PET/CT-GTV and CT-GTV volume was 84.3 cm 3 (range, 46∼364 cm 3 ) and 116.2 cm 3 (range, 58∼472 cm 3 ), respectively, showed significant differences (p = 0.0005). Conclusions: PET/CT can increase the accuracy of the staging and defining target volumes for radiation therapy fields for head and neck cancer. No significant financial relationships to disclose.