About 70 patients in the Seattle area are being notified they received radiation treatments for brain tumors from a faulty machine at Valley Medical Center in Renton.
State health officials are investigating. They have contacted other hospitals, Tacoma General and Yakima Valley Memorial, which have the same device but have apparently experienced no problems with it.
The equipment's manufacturer, BrainLab, based in Munich, Germany, sent a letter about the problem to the Renton hospital on June 5, said hospital spokesman, Perry Cooper. Cooper said the hospital stopped using the machine immediately and began contacting the patients treated the past two years.
News of the problem surfaced when the French government ordered the malfunctioning devices shut down this week after BrainLab sent letters that resulted in warnings to hundreds of brain cancer patients in France about their radiation treatments.
Cooper said the problem was with one piece of the machine -- an adapter that focuses a beam of radiation on a tumor in the brain. He said the hospital is still getting details about the malfunction.
Cooper said the machine settings were within safety margins, and hospital officials were confident no patients were harmed as a result of the malfunction.
"There is no reason to believe anyone should worry," said Cooper. "We are now working with the patients to make sure they are aware and are telling them to talk to their doctor."
Kelly Cameron, a radiation therapy inspector with the state Department of Health, said there are more than 40 hospitals and clinics using this kind of tumor-targeting radiation therapy in Washington state.
BrainLab makes collimators, which focus the radiation, and jigs that immobilize the patient's head and attach to the collimators. Valley Medical, Cameron said, was using a different jig that didn't precisely line up with the BrainLab collimator.
Cameron said, "We're going to be investigating this and checking all the other X-ray facilities in the state."
Martin Weinhouse, a physics expert at Cleveland Clinic -- the other U.S. hospital involved -- said the problem can occur when BrainLab's Novalis system is used with another manufacturer's head frame, a ring-shaped device that circles the head and is used to deliver radiation.
Weinhouse said the error involves a deviation of about 1.25 millimeters, which is similar to variations inherent in the delivery system anyway and he did not believe it would lead to serious problems.
Radiotherapy treatment involves a one-time blast by a high-energy X-ray that is aimed from several sources and focused on one point to kill the tumor. It typically has a margin of error of 0.8 millimeters when used on brain tumors.
Tacoma General just bought a BrainLab collimator but hasn't started treating patients, Cameron said, and the Yakima cancer center has been using a matching collimator and jig.
Health officials intend to review all of Valley's patient records to ensure that nobody received a dangerous amount of radiation, Cameron said.
BrainLab officials said they believed the malfunction occurred in just seven devices in use worldwide: one machine at Valley Medical, one at the Cleveland Clinic, four at hospitals in France and one in Spain.
BrainLab founder and Chief Executive Officer Stefan Vilsmeier told The Associated Press that because doctors typically allow a certain margin of error in targeting a tumor with radiation, "We don't expect any problems with the patients."
A copy of the notification sent to hospitals and dated June 4, was obtained by the AP. It said the malfunction meant the "patient is set to an unintended position" when receiving radiation treatment and added, "This may cause serious injury or death to the patient."
Dr. Georges Noel, a radiotherapy expert at the Paul Strauss cancer center in Strasbourg, said machine malfunctions were potentially harmful.
"A mistargeted machine could irradiate healthy brain tissue. ... It could kill healthy tissue," Noel said. Whether this would have a large effect on the patient depends on the part of the brain affected, he said.
Some 550 BrainLab radiotherapy machines are in use worldwide -- the largest number of them in the United States.