Imaging for assessment of radiation-induced normal tissue effects.

Imaging can provide quantitative assessment of radiation-induced normal tissue effects. Identifying an early sign of normal tissue damage with imaging would have the potential to predict organ dysfunction, thereby allowing reoptimization of treatment strategies based on individual patients' risks and benefits. Early detection with noninvasive imaging may enable interventions to mitigate therapy-associated injury before its clinical manifestation. Furthermore, successive imaging may provide an objective assessment of the impact of such mitigation therapies. However, many problems make application of imaging to normal tissue assessment challenging, and further work is required to establish imaging biomarkers as surrogate endpoints of clinical outcome. The performance of clinical trials in which normal tissue injury is a clearly defined endpoint would greatly aid in realization of these goals.