Oxygen-sensitive MRI could help personalize cancer radiation therapy

A type of magnetic resonance imaging (MRI) that shows the level of oxygen in tumors may predict which ones will respond well to radiation therapy, research led by UT Southwestern scientists suggests.

The findings, published online by the International Journal of Radiation Oncology, Biology and Physics, could offer a way to personalize therapy for the many patients worldwide who receive radiation to treat cancers. 

The results indicate that a subtle difference in the tissue oxygen level-dependent (TOLD) MRI reading – less than 1 percent – could predict which tumors would respond well to radiation therapy and which would resist it. Giving a small radiation boost to those tumors with more hypoxic signals overcame this resistance, allowing therapy to work just as well as it did in more oxygen-rich tumors. On the other hand, a higher radiation dose had no added benefit when treating the oxygen-rich tumors, meaning that healthy surrounding tissue could be spared unnecessary radiation damage in these cases.