IGRT or image-guided radiotherapy, is a new form of radiotherapy using X-ray imaging during treatments to locate and focus dosing beams more precisely on tumors. IGRT is suitable for some diagnoses, cancers, and patients, but not all. In the UC Davis Radiation Oncology department, we have three linear accelerators capable of IGRT — two Elekta Synergy machines and a Helical Tomotherapy HI-ART system.    High-quality images of the tumor or treatment area are obtained at the time of treatment permitting clinicians to quickly reposition the patient as needed on the table immediately prior to treatment.

3-D conebeam CT images give clinicians an clear view of the tumor site and surrounding bones, organs and soft tissue. Without IGRT, radiation oncologists sometimes treat a relatively large margin of healthy tissue around the tumor. IGRT allows doctors to minimize the healthy tissue exposed to the treatment beam. During a course of treatments, also IGRT enables doctors to make real-time adaptations to the treatment plan.