Image-guided radiation therapy | |
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Other names | IGRT |
Specialty | interventional radiology/oncology |
Image-guided radiation therapy is the process of frequent imaging, during a course of radiation treatment, used to direct the treatment, position the patient, and compare to the pre-therapy imaging from the treatment plan.[1] Immediately prior to, or during, a treatment fraction, the patient is localized in the treatment room in the same position as planned from the reference imaging dataset. An example of IGRT would include comparison of a cone beam computed tomography (CBCT) dataset, acquired on the treatment machine, with the computed tomography (CT) dataset from planning. IGRT would also include matching planar kilovoltage (kV) radiographs or megavoltage (MV) images with digital reconstructed radiographs (DRRs) from the planning CT.
This process is distinct from the use of imaging to delineate targets and organs in the planning process of radiation therapy. However, there is a connection between the imaging processes as IGRT relies directly on the imaging modalities from planning as the reference coordinates for localizing the patient. The variety of medical imaging technologies used in planning includes x-ray computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) among others.
IGRT can help to reduce errors in set-up and positioning, allow the margins around target tissue when planning to be reduced, and enable treatment to be adapted during its course, with the aim of overall improving outcomes.[2][3]