IGRT – IMRT:
INTENSITY MODULATED RADIOTHERAPY (IMRT)
IMAGE GUIDED RADIATION THERAPY (IGRT)
IMRT is a highly advanced form of radiotherapy utilizing computer controlled x-rays to kill cancer cells. Clinicians around the world rely on this computer-driven system and its ability to “paint” the prescribed dose of radiation onto a tumor with pinpoint accuracy. This highly individualized therapy utilizes tiny “beamlets” of radiation that vary in both shape and intensity to better match the contours of the tumor, placing more radiation exactly where it’s needed and little radiation on surrounding healthy tissue.
IMRT is used to treat many kinds of cancers including prostate, breast, head and neck, lung and brain tumors. It is also very valuable for treating pediatric malignancies. IMRT is a particularly beneficial tool if you have had radiation treatment in the past.
IGRT Image Guided Radiation Therapy (IGRT) takes IMRT one step further. Various imaging technologies such as Cone-beam ® CT scan and tracking of implanted gold fiducial markers are utilized before each daily treatment, to acquire a 3-dimensional image of the cancer area and surrounding anatomy. Using this information, the computer adjusts the radiation beam accordingly in order to precisely target the treatment to the cancer’s exact position that day. Changes as small as 1 millimeter are made to provide the greatest precision available. IGRT is the newest and most advanced system for the delivery of radiation, allowing much greater precision than proton therapy. We are one of the only centers in the world doing MRI treatment planning for prostate cancer. Prior to beginning IGRT treatment, our patients undergo this special MRI scan and a CT scan in our department. The information from the 2 scans are entered into our specialized computers and a customized treatment plan is created, tailored to fit each patient’s anatomy precisely. IGRT is typically given for only a few minutes a day, five days a week. When combined with a seed implant, this part of the treatment is approximately 5 weeks long. If given without a seed implant, the treatment is typically for 8 1/2 weeks. The IGRT component of therapy is completely painless and non-invasive. The most commonly reported side effects during treatment are slight fatigue and having to go to the bathroom more frequently. You will NOT develop any nausea, abdominal pain, hair loss, or skin burning. You will NOT lose your ability to control your bowels or bladder. You will be able to continue working full-time and should enjoy all of your regular activities.
Why is IMRT / IGRT better than Protons
- Increased dose conformality with IMRT vs. Protons
- Smaller volume of normal tissue around the prostate treated to high doses
- Less uncertainty in dose deposition and lower volumes of normal tissue treated to high doses
- More sophisticated image guidance with 3D volumetric instead of planar images
- Potential rectal sparing due to the air in the rectal balloon
- Superior clinical results.
- The ability to meaningfully spare the rectal bulb of radiation by planning a radiation dose that spares normal tissues.