Tumour Shrinkage and Contour Change during Radiotherapy Increase the Dose to Organs at Risk but not the Target Volumes for Head and Neck Cancer Patients Treated on the TomoTherapy HiArt™ System

We have shown that there were considerable changes in the volume and dose to the parotids during treatment. The changes in volume and dose to the clinical target volume were more modest in comparison. Adaptive radiotherapy planning can be helpful in improving the dose to the parotid glands. However, its role in the optimisation of the dosage to the clinical target volume is less likely to result in a significant clinical benefit.