A breakthrough external beam radiotherapy technology that is fast, precise, and has optimal dose delivery to targeted tumors while limiting damage to surrounding normal tissue, is the latest radiotherapy weapon that cancer specialists are using at Stony Brook University Medical Center to treat patients. Called RapidArc™ radiotherapy technology, the system is one of the most advanced forms of Intensity Modulated Radiation Therapy (IMRT), a computer-based form of radiotherapy that enables radiation oncologists to shoot external beams precisely into the 3-D shape of tumors in multiple small volumes. SBUMC is the only hospital in Suffolk County, N.Y., to use the system.
Computed tomography (CT) or other imaging technology is used as part of the RapidArc system to pinpoint tumor treatment. RapidArc delivers image-guided IMRT in a single rotation of the machine around the patient. During treatment the radiation beam is shaped and reshaped as it continuously delivers beams at virtually every angle in a 360-degree revolution. The system delivers beams two-to-eight times faster compared to conventional radiotherapy.
"These faster RapidArc treatments are easier on patients, who do not need to hold still for long periods of time," says Allen G. Meek, M.D., Chair of the Department of Radiation Oncology at SBUMC. "This makes patients more comfortable and simultaneously improves the quality of care, helping to optimize the precise nature of the treatment. The system also minimizes low doses of radiation in healthy tissue surrounding the tumor."
More than 15 patients have been treated with the new system, one of the radiotherapy options available to patients within the Department. To date radiation oncologists have used this form of IMRT mainly for prostate cancer patients. Dr. Meek says soon patients with head and neck cancers, breast cancer, and other forms of cancer will be treated with RapidArc.
James Erickson, 63, a salesman from Centereach, originally treated for prostate cancer with hormonal therapy, was going to opt for radiation seed treatment but changed his mind at the last minute when he heard about the IMRT option at Stony Brook.
"Each treatment is very quick and easy, and I have not missed a day of work," says Erickson. "Basically I feel normal and can go about my business."
Tae Park, M.D., Clinical Associate Professor of Radiation Oncology and Erickson's radiation oncologist, says that this form of radiotherapy for his patient so far appears to be extremely effective with little if any adverse effects.
Another of Dr. Park's prostate cancer patients, Edward Morrell, of East Hampton, has received RapidArc IMRT and says each treatment is completed quickly. Outside some fatigue, he has felt well during the eight-week daily treatment schedule.
"This form of IMRT for early stage prostate cancer patients appears particularly effective, as the image-guided technology enables us to pinpoint treatment to the prostate and reduce the dose to surrounding healthy tissue," says Dr. Park, describing the two cases.
Drs. Meek and Park point out that with the new system, SBUMC offers a highly sophisticated form of IMRT. Prior to each treatment, the patient is imaged in the exact position in which the treatment will be delivered to assure precise localization of the center of the rotation of the arc, thus assuring optimum treatment delivery.
Both doctors emphasize that with the image-guided system and SBUMC's entire radiotherapy armamentarium, the departmental approach to improved tumor targeting and greatly minimizing irradiation to normal surrounding tissue continues to advance.
"In some cases involving IMRT, improved targeting may also make it possible to deliver higher radiation doses to the tumor and thereby increase the likelihood of local tumor control," adds Dr. Meek.
Developed by Varian Medical Systems, RapidArc uses a multi-leaf collimator (MLC), a device with 120 computer-controlled mechanical leaves or fingers that move to create apertures of different shapes and sizes. During treatment the specialized software algorithms vary three parameters simultaneously: the speed of rotation around the patient, the shape of the MLC aperture, and the dose delivery rate. Radiation Oncologists and Radiation Therapists use all of the elements of the system to tailor patient treatment, based on each patient's unique anatomy and tumor size, shape, and position within the body.
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