Physiologic [18F]fluorodeoxyglucose uptake of floor of mouth muscles in PET/CT imaging: a problem of body position during FDG uptake?

OBJECTIVE Assess the influence of 2 different patient positions during [18F]fluorodeoxyglucose (FDG) uptake phase on physiologic FDG accumulation of the floor of mouth (FOM) muscles. STUDY DESIGN A prospective study design was used. METHODS Two hundred prospectively enrolled patients were included in the study: (a) head and neck cancer (HNC) patients in supine or (b) sitting position, (c) patients with other malignant tumours in supine or (d) sitting position. An intra-individual analysis was done on patients (b) and (d) when such scans were available. Maximum standardized uptake values without correction and corrected for blood pool activity were assessed. RESULTS The inter-individual analysis (sitting vs supine) revealed no significant differences (P = 0.17 and P = 0.56). The subgroup analysis on the patients with HNC (P = 0.56 and P = 0.15) and in patients with other malignancies (P = 0.14 and P = 0.08) revealed no significant difference; neither did the intra-individual analysis. CONCLUSIONS The supine or sitting position during the uptake phase for FDG-positron emission tomography/computed tomography has no effect on the amount and distribution of physiologic FDG activity in the muscles of the FOM.