Role of 18F-FDG PET/CT in pre and post treatment evaluation in head and neck carcinoma

Figure 17 False positive positron emission tomography/computed tomography result due to post treatment infection. A T3N0M0 left supraglottic squamous cell carcinoma showed edema and necrosis at the tumor site (red arrows) on contrast-enhanced computed tomography (CT) (A and B) at 5 wk after chemoradiation and increased uptake on positron emission tomography/CT (PET/CT) (C and D) at 10 wk. The patient had severe throat pain and fever. A residual tumor can not be excluded, therefore endoscopy with biopsy was performed showing radiation-induced inflammation, tumor necrosis and superimposed actinomycosis causing a false positive result on PET/CT. Due to lack of viable tumor, no salvage surgery was performed. The patient was disease free at two-year follow up.