Fig. 1From: Early post-treatment 18F-FDG PET/CT for predicting radiation-induced hypothyroidism in head and neck cancerExamples of thyroid visual grade in our cohort (Upper: maximum intensity projection, lower: transaxial view). A Grade 1, thyroid uptake less than blood pool uptake; B grade 2, thyroid uptake equal to or higher than blood pool uptake but less than liver uptake; C grade 3, thyroid uptake equal to or higher than liver uptakeBack to article page