ESTRO 2025 - Abstract Book

S1035

Clinical – Head & neck

ESTRO 2025

Results:

A total of 23 patients were included and 681 sets of FBCT were obtained in this study. Bilateral parotid glands, submandibular glands, thyroid, spinal cord and all target volumes showed an absolute percentage volume and/or DSC difference exceeding 2.5%, with a linear decrease (R 2 > 0.7). The change of DSC was shown in Figure 1. The V 100% of PTV2 gradually descended from over 95% in weeks 1-5 to below 95% in weeks 6-7. The D mean of bilateral parotid glands and thyroid, D 1% of the brainstem, and D max of the spinal cord increased as the radiotherapy course progressed, which were shown in Figure 2.