Thyroid dose-volume thresholds for the risk of radiation-related hypothyroidism in nasopharyngeal carcinoma treated with intensity-modulated radiotherapy-A single-institution study.

We recommend V25Gy  ≤ 60%, V35Gy  ≤ 55%, and V45Gy  ≤ 45% as the "stringent" DVH line, and V25Gy  > 95%, V35Gy  > 90%, and V45Gy  > 75% as the "inhibition" DVH line, under the precondition of not compromising the target coverage. These findings could help in the design of individual treatment plans and, eventually, to lowering of HT prevalence.