PurposeWe investigated radiation-induced changes in the salivary glands, 6weeks after RT, using MRI. Materials and methodsEighteen oropharyngeal cancer patients were treated with salivary gland sparing IMRT. All patients received a 3T MRI exam before and 6weeks after the end of RT, including a T1-weighted (T1w), a T2-weighted (T2w), and a dynamic contrast-enhanced (DCE) MRI.For both time points separately, the parotid and submandibular glands were delineated on the MR images. Differences in median signal intensity and signal variation within the glands were tested for significance. Correlations were studied between the MR changes and the planned RT dose. ResultsThe volume of the glands reduced significantly by 25%. The T1w signal decreased by 10% and the T2w signal increased by 23%. The kep value decreased, while the ve increased. A correlation of the changes in T2w signal with the mean dose was found in both glands. ConclusionsOverall radiation-induced changes and volume loss were observed in the parotid and submandibular gland using MR. The observed differences indicated an increased water content such as found in oedema. The overall changes could be related to the mean dose, with a slightly greater impact in the high dose area.