IGRT, Department of Radiation Oncology, East Carolina University, Greenville, North Carolina

        Both patients and their organs move. That means the tumor is also moving. This motion can result in the radiation beam missing its target. The most advanced method to evaluate and correct for this motion is to use Image Guided Radiation Therapy (IGRT). While many forms of IGRT are possible the most advanced and accurate employs a diagnostic CT scanner that can image the tumor just prior to therapy. If the tumor has shifted, the radiation beams can then be corrected before the radiation treatment.
        The Siemens Primatom, available exclusively at ECU, combines the highest quality linear accelerator for treatment with a diagnostic quality CT scanner within the treatment room.
        This combination allows for daily IGRT for any patient who requires this therapy. Unlike other forms of IGRT, the CT on rails approach can be used for any part of the body from head to toe. Diagnostic quality images eliminate uncertainty, as is often seen on clinically limited ultrasound based IGRT systems.

Prostate IGRT Video

This video shows how the Siemens Primatom IGRT software is being used in this patient with prostate cancer. A daily CT (orange axial CT image) is obtained to ensure that the current position of the prostate matches as closely as possible its position the day the treatment was planned (gray axial CT image). Had the prostate moved due to rectal gas or a full bladder, the software would have corrected for this.
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IGRT Demo

Step 1: the radiation therapist positions the patient by aligning the initial setup marks with the treatment positioning lasers.
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Step 2: the radiation therapist rotates the treatment table 180 degrees to obtain a CT scan of the patient that is limited to the treatment area.
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Step 3: The planning CT scan is compared with the CT just obtained using the IGRT Siemens Primatom software (see Prostate IGRT Video) to determine if a shift in patient position is necessary. Once the shift is determined by the software, the therapist makes the necessary adjustments to the treatment couch.
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