Image guidance and the new practice of radiotherapy: what to know and use from a decade of investigation.

Over the past decade, fundamental advances in image-guided radiation therapy (IGRT) have been made that are now being implemented in clinical practice. Imaging technologies to direct and confirm beam accuracy at the time of radiotherapy delivery have been intensively researched and developed. More recently, these imaging data have been used to evaluate and even modify the daily dose delivery of intended treatment plans. The rationale for the use of IGRT, to improve tumor control while limiting normal tissue toxicity, is a universal goal in radiotherapy. Avoidance of unexpected under- or overdosing during treatment is the most important benefit of IGRT, and has led to its integration into the use of advanced radiotherapy planning/delivery technologies for many clinical applications. Evidence-based strategies to effectively use IGRT in the clinic are still emerging. The evolving role of IGRT and some proposed strategies to exploit its potential benefits in the clinic will be presented, emphasizing the perspective of the radiation clinician. Practical strategies will be proposed to exploit the potential benefits of IGRT technologies in the clinic.