ABSTRACT
Image-guided radiation therapy (IGRT) is a broad field (Verellen et al. 2008; Chen et al. 2009) but will be simplified for this discussion. For the purpose of this work, we will define IGRT as the use of radiographic imaging, either projection or volumetric, to align the patient with the radiation isocenter prior to each treatment. This definition neglects some important developmental technologies such as 3D surface optical imaging (Vision RT Ltd., London, UK) and radiofrequency beacon fiducial tracking (Calypso Medical Technologies, Inc., Seattle, Washington), but many of the informatics issues encountered in radiographic IGRT are also applicable to nonradiographic technologies.
