Local Anatomic Changes in Parotid and Submandibular Glands During Radiotherapy for Oropharynx Cancer and Correlation With Dose, Studied in Detail With Nonrigid Registration

General shrinkage and deformation of irradiated glands was seen. The spared glands showed few changes. These changes were assessed by a nonrigid registration method, which effectively described the local changes occurring in the head-and-neck region after external beam radiotherapy.