2016_Head & Neck COURSE BOOK

Normal tissue tolerance

• Serial tissue: Dose constraints – Tolerance is not related to the irradiated volume  – Max dose – E.g. ’max 50 Gy to spinal cord’ ’max 54 Gy to optic chiasm’ • Parallel tissue: Dose volume constraints  – Tolerance is dependent on the irradiated volume – DVH constraints – E.g. ’mean dose below 30 Gy to oral cavity’, ’mean dose  below 26 Gy to parotids’, ’2/3 of larynx below 50 Gy’