IGRT (Image-guided radiation therapy) is the use of frequent imaging during a course of radiation therapy to improve the precision and accuracy of the delivery of the treatment.
IGRT is used to treat tumors in areas of the body that are prone to movement, such as the lungs (affected by breathing) and prostate gland, as well as tumors located close to critical organs and tissues. It is often used in conjunction with intensity-modulated radiation therapy (IMRT), an advanced mode of high-precision radiotherapy that utilizes computer-controlled x-ray accelerators to deliver precise radiation doses to a malignant tumor or specific areas within the tumor.
In IGRT, machines that deliver radiation, such as a linear accelerator, are equipped with imaging technology so that the physician can image the tumor immediately before or even during the time radiation is delivered, while the patient is positioned on the treatment table. Using specialized computer software, these images are then compared to the images taken during simulation. Any necessary adjustments are then made to the patient’s position and/or radiation beams in order to more precisely target radiation at the tumor and avoid healthy surrounding tissue.