WE-E-BRA-01: Introduction to Treatment Assessment of Radiation Therapy Using MR Functional Imaging and Its Application to Intracranial Stereotactic Radiosurgery.

UNLABELLED

Recent developments in MRI have substantially improved its performance, making it a potentially powerful tool for not only diagnosis but also therapy. Treatment assessment using MR functional imaging is the process of using MR functional imaging before and/or during and/or after a course of radiation therapy (RT) to assess treatment responses and as such to optimize therapeutic outcome. Various MR functional techniques including, but not limited to, diffusion weighted imaging (DWI), diffusion tensor imaging (DTI), MR spectroscopy (MRS) and dynamic contrast enhanced (DCE) imaging, have been investigated to assess therapeutic outcome in radiotherapy. DCE-MRI uses fast imaging and contrast material to assess changes in the microvascular environment. MRS can be used to assess non-invasively biochemical changes caused by RT. Diffusion imaging techniques are used to assess the changes of cellular density and neural fibers caused by RT. In this lecture, the application of functional imaging to the assessment of stereotactic radiosurgery is illustrated. Stereotactic radiosurgery (SRS) is effective in treating brain tumors, but radiation may cause injury to normal brain tissues (e.g., white matter), compromising sensory and neurocognitive brain functions. DTI can be used to track neural fibers and assess radiation-induced damages in white matter. Furthermore, DCE-MRI can be used to interrogate tumor biology and treatment-related changes in tumor vasculature after SRS. These Issues related to treatment-related changes will be discussed. This lecture will provide an overview of the MR functional imaging along with its application to the assessment of stereotactic radiosurgery.

LEARNING OBJECTIVES

1. Understand the principles of MR functional imaging techniques 2. Understand the issues related to MR functional imaging 3. Understand the clinical application of MR functional imaging in assessing treatment response of SRS.