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Department of Radiation Oncology

Department of Radiation Oncology

Image Guided Radiation Therapy (IGRT)


The UC Davis Radiation Oncology department was the first facility in the Sacramento Valley to utilize IGRT technology and, as a result, is a recognized, national leader in this technology.  The department offers three linear accelerators capable of IGRT: two Elekta Synergy machines and a Helical TomoTherapy HI-ART system.

IGRT, or image guided radiation therapy, is a new form of radiotherapy using X-ray imaging during treatments to locate and focus dosing beams more precisely on tumors.  IGRT brings scanning and radiation equipment together to permit the doctor to see the area of the body almost simultaneously while treating.

Prior to IGRT, physicians were unable to know the daily status of the tumor or tissues.  With IGRT, more frequent imaging just prior to daily treatment enables physicians to pinpoint the position of the tumor and the surrounding normal tissues just as they are at time of treatment.  With these more defined targets, patients can receive higher, more precise doses of radiation for better control of cancer and minimal effect to surrounding, normal tissues.

IGRT also enables doctors to make real-time adaptations to the treatment plan. The high-quality images of the tumor or treatment area obtained at the time of treatment allow clinicians to quickly reposition the patient as needed on the table. 3-D cone beam CT images give clinicians a clear view of the tumor site and surrounding bones, organs and soft tissue.  With IGRT, radiation oncologists no longer need to treat a relatively large margin of healthy tissue around the tumor, but can minimize the amount of healthy tissue exposed to the treatment beam.

IGRT is suitable for some diagnoses, cancers and patients, but not all.