Adaptive 18Fluoro-2-deoxyglucose Positron Emission Tomography/Computed Tomography-based Target Volume Delineation in Radiotherapy Planning of Head and Neck Cancer

The adaptive threshold method may be of benefit when used to define the target volume before the start of radiotherapy. This method was not beneficial during radiotherapy because the software is not sensitive enough to distinguish tumour from background and define a volume. 18FDG PET/CT-guided volumes delineated by automatic adaptive thresholding methods should only be used for dose escalation with the pretreatment imaging.