sentence: In patients suffering from squamous cell carcinoma of the head and neck , studies have looked at the relationship between hypoxia and FDG uptake in both lymph nodes ( one cumulative series of 36 patients by Gagel et al. ) and primary tumours ( two series of patients suffering from SCCHN , respectively , one on 12 patients by Thorwarth et al. and one reporting on 38 patients by Rajendran et al. ) with seemingly conflicting results [ 19 – 22 ] .