Intensity Modulated Radiation Therapy (IMRT)
Eleanor T. Snow Radiation Oncology Center
Orange Regional Medical Center
707 East Main Street
Middletown, NY 10940
Orange Regional Medical Center is using the latest technological advancement to fight the battle against cancer. The new technique, called Intensity Modulated Radiation Therapy or IMRT, allows doctors to more precisely tailor the treatment dose to match the target tumor, while sparing the surrounding normal tissues.
IMRT requires technologically sophisticated, computerized treatment planning and treatment delivery systems. Conventional cancer treatment planning is accomplished by manually adjusting simulated radiation beams to achieve a clinically acceptable dose distribution in an accurate computer model of the patient. With IMRT, the physician prescribes the desired dose distribution first. A complex computer program then determines the radiation beam intensities to meet the treatment objectives.
The IMRT beams are shaped by a multileaf collimator, a computer-controlled device located in the head of the treatment machine, the linear accelerator. "With IMRT, we are able to manipulate the beam of radiation and approach the target area at a variety of different angles. We are then able to deliver a smaller beam with a stronger and more evenly distributed dose," says Radiation Oncologist Dr. Thomas Eanelli.
IMRT treatments are ideally suited for cancer sites where the critical normal structures are very close to the target tumors. For head and neck cancers, very high doses can be delivered to the target areas while limiting doses to salivary glands, spinal cord and other critical tissues. For prostate cancers, lower doses can be given to the bladder and rectum when compared to conventional treatment techniques.
"IMRT allows for improved quality of life during radiation therapy due to less side effects in surrounding tissue. There are significantly improved clinical outcomes," stated Hai Luo, PhD, Orange Regional Medical Center's Chief Medical Physicist.
Orange Regional Medical Center uses the IMRT planning system produced by Varian Eclipse based in Las Vegas, Nevada.