Radiation therapy is an effective cancer treatment that is constantly being transformed by technological innovation. Dedicated devices for fraction-by-fraction imaging and guidance within the treatment room have enabled image guided radiation therapy (IGRT) allowing clinicians to pursue highly conformal dose distributions, higher dose prescriptions, and shorter fractionation schedules. Capitalizing on IGRT-enabled accuracy and precision requires a strong link between IGRT practices and planning target volume (PTV) design. This is clearly central to high quality, safe radiation therapy. Failure to properly apply IGRT methods or to coordinate their use with an appropriate PTV margin can result in a treatment that is 'precisely wrong'. The white paper summarized in this executive summary recommends foundational elements and specific activities to maximize the safety and effectiveness of IGRT.