Tumors are moving targets. Image-guided radiation therapy (IGRT) uses dynamic tumor tracking to pinpoint the exact size, location, and coordinates of a tumor just prior to and during treatment. Ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), position emission tomography (PET), and x-ray imaging may be used to obtain detailed imaging of pelvic contents. The increased precision of IGRT allows for higher doses of radiation to be focused and delivered directly to tumors and cancer cells.
IGRT is used in conjunction with external radiation, specifically 3D conformal radiation therapy, intensity modulated radiation therapy (IMRT) or stereotactic body radiotherapy (SBRT). As it is simply the technology used to deliver radiation, IGRT itself has no side effects. Any side effects that are experienced are due to the radiation. As the dose of radiation is restricted to targeted areas in the prostate, exposure to healthy surrounding tissue is minimized and the patient can expect to experience fewer side effects following treatment.
Before Image-guided Radiation Therapy
When patients are selected for image-guided radiotherapy, a simulation is performed and baseline images are gathered to plan radiation therapy. While the overall treatment plan is created and supervised by the radiation oncologist, the delivery of radiation therapy involves a treatment team. About one week prior to the first radiation therapy treatment, radiodense gold marker(s) may be placed inside the body near or in the tumor to help the treatment team identify the area. Your skin may be marked with colored ink to help align and target the radiation equipment.
During Radiation Therapy
Prostate cancer radiation treatment is administered daily, Monday through Friday, for 5-9 weeks. Generally, the procedure itself takes between 15 and 45 minutes. You will be placed into position by the assistance of the nurse. Immediately before and during the time radiation is delivered, the radiation therapist may take an image of the tumor and use specialized computer software to compare this image with those taken during the simulation. The radiation therapist or nurse may adjust your position and/or radiation beams in order to more precisely target radiation at the tumor and avoid healthy surrounding tissue. Imaging performed prior to or during radiation therapy sessions, as well as the delivery of targeted radiation is painless. During a radiation session, you may see or hear equipment moving around you.
After Image-guided Radiation Therapy
You may experience early and/or late side effects as a result of this treatment. Common early side effects include tiredness, fatigue, and skin problems, such as sensitive, red, irritated, or swollen skin. Other early side effects consist of mouth sores, hair loss in the treatment area, nausea, vomiting, and headaches. Following radiation treatment, you will be checked on a regular basis by your radiation oncologist for recurring and new cancers, and the possible occurrence of late side effects.