Emerging Magnetic Resonance Imaging Technologies for Radiation Therapy Planning and Response Assessment

Functional and molecular MRI techniques are capable of measuring biologic properties of tumor tissue. Knowledge of these biological properties may improve radiation treatment by more accurately identifying tumor volumes, characterizing radioresistant subvolumes of tumor before radiation therapy (RT), and identifying recurrent disease after RT. Intravoxel incoherent motion MRI, blood oxygenation level-dependent MRI, tissue oxygenation level-dependent MRI, hyperpolarized ¹³C MRI, and chemical exchange saturation transfer MRI are relatively new MRI techniques that have shown promise for contributing to RT planning and response assessment. This review critically evaluates these emerging MR techniques, their potential role in RT planning, utility to date, and challenges to integration into the current clinical workflow.