Image Guided Radiation Therapy

With increasing emphasis on reducing the volume of radiation therapy fields while maintaining or improving precision of treatment and reducing radiation-related normal tissue toxicity, treatment position verification and correction before delivering radiotherapy had gained major importance. A variety of techniques have been developed that can accomplish this goal with aplomb, albeit each with its own set of limitations. The best method that eliminates uncertainties in treatment without a huge cost remains to be defined, but it is clear that carrying out “high precision radiotherapy” without periodic image guidance is as accurate as shooting in a dark room. This review discusses the concept of image guidance in radiotherapy, various techniques available along with expected benefits and pitfalls of these systems.