Targeted Beams: New Machine
Speeds Radiation Treatment
September 16, 2008
Attorney James Tuffin followed his usual daily routine last week: He ran five miles and drove to his office on suburban Long Island. In between, he stopped at Advanced Radiation Centers in North Hills, N.Y. There, he drank a quart of water, lay down on a treatment table and watched as a high-tech linear accelerator rotated around him for 90 seconds, blasting his cancerous prostate with radiation.
"On a good day, I'm in and out in a half-hour," says Mr. Tuffin, 54 years old, who was midway through his scheduled 45 treatments. "And most days are good days."
Ever since scientists discovered that radiation could fight cancer but cause great harm to other cells, the search has been on to maximize the dose aimed at target areas while sparing healthy surrounding tissue.
The technology has taken a quantum leap in recent years. Computers now make three-dimensional models of the target area. Doctors can sculpt the radiation beam to the target's exact shape and modify the intensity to protect nearby organs.
Among the latest advances is RapidArc, which speeds up the delivery of radiation dramatically. Treatments that once took five to 10 minutes are finished in less than two minutes.
For patients getting daily treatments over many weeks, that's far less time lying still on a treatment table. More important, the speed reduces the chances that the patient might shift position, causing the radiation to miss the target. Even when staying still, internal organs move subtly due to breathing or digestion.
"Everything we do is about precision, down to the sub-millimeter," says Michael Lafont, a physicist with Varian Medical Systems Inc. of Palo Alto, Calif., RapidArc's maker.
RapidArc won clearance from the Food and Drug Administration in January. Varian, the industry leader in radiation technology, says the system has been installed in 30 centers in the U.S. and Europe and is on order at 150 more.
"We're very excited about it," says Margie Hunt, director of external-beam radiation planning at Memorial Sloan-Kettering Cancer Center in New York, which is expecting to install the RapidArc equipment by the end of the year.
RapidArc is used in conjunction with other recent innovations, including intensity-modulated radiation therapy, which lets doctors vary the beam's strength, and image-guided radiation therapy, which pinpoints the target using CT scans.
"The radiation from the machine is many times greater than it was 40 years ago, but it's much safer because it's more precise," says Shawn Zimberg, medical director of Advanced Radiation Centers, which has four facilities in suburban New York.
Side effects from radiation therapy are generally due to collateral damage to surrounding tissue, so the more precisely it can be aimed, the fewer there are. "I feel a little sleepy in the afternoon, but it doesn't prevent me from doing my work," says Mr. Tuffin. As for the treatment itself, "You don't feel anything."
Some 70% of all cancer patients in the U.S. undergo radiation—either alone or with chemotherapy or surgery. RapidArc is particularly suited to cancers in close proximity to delicate organs. For head and neck cancers, it can help doctors skirt the salivary glands. For prostate cancer, it helps avoid the bladder, the rectum and the seminal vesicles.
The cost of RapidArc is similar to other radiation therapies. It's covered by Medicare and most insurers.
Other forms cancer therapies also aim to spare healthy tissue; doctors may recommend one over another depending on the type, size and position of the cancer and other factors. Data comparing treatments are difficult to come by and often take years to evaluate. The reduced risks and shorter treatment time with RapidArc may make more patients choose radiation if they have options.