Novel Imaging For Treatment Planning Or Tumor Response

Anatomic imaging has long represented an integral part of modern radiotherapy, from planning, image-guidance to response evaluation. Functional imaging modalities now allow oncologists to supplement these anatomic images with functional maps, to elucidate the underlying biologic processes of cancer and allow delineation of both physical and biologic target volumes. Prescription of dose to this combination, commonly referred to as dose painting, represents an attractive avenue to further improve the therapeutic ratio of radiotherapy. This chapter focuses on the integration of novel imaging techniques and their role in delineating biologic radio-therapeutic targets, organized by well-known principles in radiobiology: tumor repopulation, reoxygenation, and repair. Focus is largely on clinically available imaging modalities, including positron emission tomography (PET) with various targeted radionuclides and functional magnetic resonance imaging (MRI). Other potential preclinical techniques are highlighted where relevant, particularly as they apply to promising translational concepts. Emphasis is placed on integration into treatment planning, adaptive treatment modifi cation, and posttreatment response assessment.