Image Guided Radiotherapy (IGRT)

IGRT or image-guided radiotherapy is a new form of radiotherapy using X-ray imaging during treatments to locate and focus beams more precisely on tumors. It is the process of frequent two and threedimensional imaging, during a course of radiation treatment, used to direct radiation therapy utilizing the imaging coordinates of the actual radiation treatment plan. The goal of the IGRT process is to improve the accuracy of the radiation field placement, and to reduce the exposure of healthy tissue during radiation treatments . Material and Methods Three-dimensional (3D) IGRT would include localization of a cone-beam computed tomography (CBCT) dataset with the planning computed tomography (CT) dataset from planning for example. Twodimensional (2D) IGRT would include matching planar kilovoltage (kV) radiographs fluoroscopy or megavoltage (MV) images with digital reconstructed radiographs (DRRs) from the planning CT. 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 . Results and Conclusion -٣D conebeam CT images give clinicians a clear view of the tumor site and surrounding bones, organs and soft tissue . During a course of treatments, IGRT enables doctors to make real-time adaptations to the treatment plan. IGRT allows doctor s to minimize the healthy tissue exposed to the treatment beam. Without IGRT, radiation oncologists sometimes treat a relatively large margin of healthy tissue around the tumor so IGRT has the potential to significantly improve the therapeutic ratio by reducing toxicity and improving control rates .