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Varian Medical Systems' new RapidArc™ radiotherapy delivers a complete IMRT treatment with one rotation of the treatment machine.

Cancer patients are spending less time on the table while receiving better-targeted doses of radiation therapy than ever before.

That's the goal behind continued advancements to linear accelerators, as hospitals in Mississippi and elsewhere upgrade the workhorse machines that fuel today's radiation oncology departments.

At North Mississippi Medical Center in Tupelo, spring 2009 marks the arrival of Varian Medical Systems' RapidArc™ radiotherapy technology — a first-in-the-state addition that stands to cut treatment times in half or more.

It's an enhancement of the machine's ability to deliver Intensity Modulated Radiation Therapy, said radiation oncologist Bert Duncan, MD.

"If you think of a patient lying on a table, the less time they lay there, the less movement is a problem," he said. "It reduces the treatment time for the patient, and it allows us to minimize the opportunity for motion to occur."

With standard IMRT, treatment times might be in the range of 10 to 20 minutes, Duncan said. With the addition of RapidArc, those times may be as much as two to even eight times shorter, according to Varian.

At the same time, the technology promises the potential for better dose distribution while also minimizing the radiation received by surrounding tissues.

RapidArc is able to achieve this with a single 360-degree rotation of the machine's device, thanks to a better-tailored planning algorithm. It projects the treatment area as a three-dimensional space rather than a series of flat slices.

"It improves the ability to make the radiation fit the tumor," Duncan said. "At the same time, there is a lower dose of radiation delivered outside the planned field."

NMMC's arsenal of cancer-fighting technologies also involves Image-Guided Radiotherapy, combining imaging and treatment on one machine to more accurately pinpoint the area which will receive radiation.

"I think after our therapists started using image-guided therapy, they're convinced that's how they would want to be treated," Duncan said.

The hospital's move to add RapidArc technology has been in the works for more than a year.

"We looked at our patient numbers and types, and we felt like there would be a benefit to our patients," Duncan said. "It would allow us to maximize the number of patients we could treat in that fashion, so it just seemed to make sense."

Given that the new technology speeds treatment time, the ability to treat more patients in a day would also help offset the investment on the hospital's part for the upgrade.

Among the hospital's oncology patients, some 25 to 40 percent receive radiation therapy through IMRT.

"It's really designed for patients whose treatment area is in a place where you're concerned about affecting critical structures," Duncan said. "Also, not every patient can tolerate being immobilized for treatment."

Additionally, he said, a machine which might be used to treat both palliative patients and curative patients can allow clinicians to tailor the treatment to what each patient needs.

The RapidArc technology is also set to debut later this year at St. Dominic Cancer Center in Jackson. There, the addition of the Novalis Tx™ platform for non-invasive image-guided radiosurgery should also be in place by the last quarter of this year.

A product of Varian along with software-system-creator BrainLAB, the device allows doctors to treat tumors and non-malignant growths from outside the body. St. Dominc's is bringing in the system as a replacement to one of its current linear accelerators, medical physicist Veeresh Michael said.

"It's a radiosurgery machine, but it is also a general-purpose machine in that a broad segment of patients can be treated with it," he said.

"It's like the high-end Cadillac. There are less than 50 installed in the United States, and we'll be the first site in Mississippi to get this machine later this year."

A major attraction for the upgrade was the ability to use the new machine for a wide range of applications, including image-guided radiotherapy (IGRT). To accommodate the Novalis Tx, St. Dominic's is building a new vault to house the machine rather than trying to retrofit its existing space for the new machine's requirements.

"There's the physical construction process, then commissioning it and getting it ready for treatment with all these new modalities," Michael said.

"It is a huge investment the hospital is making, but we're getting a real bang for the buck."

The IGRT enhancement has also been in use for more than a year at St. Dominc's, as the Jackson area's only freestanding cancer center works to keep up with the latest technology.

Marking its 10-year anniversary recently, the center has witnessed IMRT technology evolve from being available only at major research centers to arriving at the community cancer-center level. At the same time, Michael said, the development of more-sophisticated treatment plans and more-customized radiation delivery has made for doses that can be at once safer and stronger for patients.

"I think there will be more of a combined approach in terms of hormonal therapy and targeted therapies, where you have very specific treatments for diseases," he said.

"Right now, we're customizing it to the individual tumor and patient. What if you can get down to the biological level? That's something I expect to see within my career."

While diagnostic and treatment technologies continue to evolve, support services remain a key aspect to centers like St. Dominic's – from oncology education and cancer dieticians, to programs like the Camp Bluebird retreat for adults.

"I think there is definitely an emphasis on the holistic care of patients – the whole process of going through treatment and survivorship," Michael said.

"When it comes to technology, there are constantly new things coming out that would be beneficial to some. What we have to do is invest in those things that will be beneficial to the greatest number of our patients."

Tags:

Bert Duncan, BrainLAB, Intensity Modulated Radiation Therapy, North Mississippi Medical Center, Novalis Tx™, radiotherapy, St. Dominic Cancer Center, Varian RapidArc™, Veeresh Michael

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