IMRT Provides Safer, More Effective Radiation Therapy
The science of radiation therapy has long been a double-edged sword. How can we maximize the dose without harming normal, healthy tissue? Advances in radiation therapy delivery have brought us much closer to achieving that balance.
Lynn Riordan, R.T.(T), standing with the Linear Accelerator |
The practice of Radiation Therapy has long been a delicate balance. How can the dose to the cancer be maximized without harming normal, healthy secondary tissue? Advances in radiation therapy delivery have brought us much closer to that balance.
Intensity Modulated Radiation Therapy (IMRT) – one of the most significant technological advancements in cancer treatment in the last 30 years – lets radiation oncologists treat tumors which are near radiosensitive organs such as the eye, spinal cord or rectum. It also allows them to treat recurrent cancers in sites that have received previous radiation doses, and treat tumors with a higher total dose than ever before.
The Yale-New Haven Shoreline Medical Center (YNHSMC) now brings this technology close to home for the Shoreline community. Our radiation oncology service offers state-of-the-art treatment planning and dose delivery with a CT/simulator and linear accelerator equipped with a multi-leaf collimator (MLC). This allows the radiation dose to conform to the three-dimensional shape of the tumor by controlling the intensity of the radiation beam to focus a higher radiation dose to the tumor while minimizing radiation exposure to surrounding normal tissues.
Ann Gilhuly, R.T.(T), standing with the CT-simulator |
In treatment planning, we determine the dose intensity pattern by using the individual patient’s 3-D computed tomography (CT) images in conjunction with computerized dose calculations. Typically, we use combinations of several intensity-modulated fields coming from different beam directions to produce a custom-tailored radiation dose that maximizes tumor dose while also limiting dose to nearby normal tissues. In other words, multiple beams are directed at the tumor from different angles. This beam combination results in a radiation dose distribution that conforms to the shape of the tumor. At the same time, nearby normal tissues receive lower doses compared to conventional radiation techniques. As a result of this technology, our radiation oncologists can give higher doses to improve the chances for cure while reducing dose to normal organs and minimizing side effects.
While IMRT is beneficial for many types of cancer, it has proven especially useful in treating prostate cancer, because the radiation oncologist can safely escalate the dose delivered to the prostate without increased toxicity to the rectum and bladder. At Yale-New Haven Hospital, more than 300 patients with prostate cancer have been treated with IMRT over the last 5 years and the results have been very positive. Complications in particular have been extremely low. Overall cure rates with IMRT are higher than older radiation techniques, and now compare favorably with radical prostatectomy results.
In addition to prostate cancer, IMRT seems most beneficial with head and neck cancers, brain tumors and some pediatric cancers. IMRT is currently being investigated for other cancers, such as lung, breast, uterine or ovarian. With tumors in the head and neck region, IMRT may prove to reduce side effects because it allows reduced radiation doses to the eyes, the visual nerve pathways and the salivary glands, reducing the risk for blindness or dry mouth.
The physicians and staff in the department of radiation oncology at the Yale-New Haven Shoreline Medical Center are working together with Yale-New Haven Hospital and Yale University School of Medicine to provide the safest, most up-to-date care available for patients in the Shoreline communities.
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