Quantitative/Objective Analyses of RT-Induced Late Normal Tissue Injury Using Functional Imaging

There are several ways to score normal tissue injury. Imaging is an attractive tool since it allows for an objective assessment of normal tissue changes in vivo. Regional changes in tissue structure/function, detected by imaging, can be related to the different radiation doses delivered to different regions. This approach has been used for several organs, and for some, there is a clear dose–response relationship for changes in normal tissue (e.g., lung density or perfusion). Further, degree/extent of changes in regional imaging may be associated with changes in global organ function. Future improvements in imaging (e.g., more functional versus structural assessments) will afford additional opportunities for studies to better understand RT-induced normal tissue injury.