File Type: 2000

File Version: 文件

Brief Description:

Magnetic resonance imaging has been called the most important tool for doctors since the X-ray was invented more than 100 years ago, but an article in The New York Times on Friday is calling the safety of the machines into question.

The number of MRI scanners in the United States has soared from a handful in 1980 to about 10,000 today, and the magnets have quadrupled in power during that time. With the increase of diagnostic scans being performed, which can detect dozens of serious ailments such as tumors and stroke, medical experts are concerned about the number of careless accidents that have caused serious injury and even death.

In 2001, Michael Colombini, 6, was killed while undergoing an MRI when an oxygen tank flew out of the hands of an anesthesiologist toward the machine, hitting him in the head.

In 2003, a New Mexico woman sued a Los Alamos hospital, claiming the magnetic pull of an MRI caused an oxygen tank to hit her in the back.

In 1992, a 74-year-old woman hemorrhaged and died after an aneurysm clip in her brain shifted while she was on a table preparing for an MRI.

Dr. Emanuel Kanal, who helped write the MRI safety guidelines for the American College of Radiology, says dozens of similar accidents occur each year due to "pilot error."

"It's my opinion that the majority of the incidents that have occurred … have been as a result to what I referred to as pilot error or how the procedure was performed," Kanal said. "I believe there is a strong 'it couldn't happen here' mentality. I don't believe people are quite aware of the potential problems that can occur, the substantial severity that could occur."

Dr. Moriel NessAiver is a physicist who teaches MRI safety to hospital personnel at the University of Maryland, where he is an assistant professor of radiology. He demonstrated for "Good Morning America" the dangers of bringing metal into a room with the powerful MRI magnets.

"Overall, it is an extremely safe procedure, but like all powerful pieces of equipment, there are rules that have to be followed," NessAiver said.

NessAiver said the cardinal rule for MRI safety is that no iron-like metal be allowed in the MRI room. He demonstrated how a keychain worn around the neck -- a common mistake when people come into the MRI room -- can be enough to pull a person toward the powerful MRI magnet. He added the damage done by a small key is minimal; injuries increase in severity with the size of the metal object.

The American College of Radiology recently toughened its "voluntary" guidelines for MRI personnel.

"I think we need to continue to focus and not let our efforts lapse," NessAiver said. "We need to educate all hospital, fire and police personnel who may need to come to an MRI facility."

Most surgically implanted devices, such as bone pins, artificial joints and titanium hips, are made of non-magnetic material. Teeth crowns and dentures are also safe.

NessAiver offered these safety tips for people about to get an MRI:

 Ensure the facility is accredited

 Ensure proper screening

 Declare implanted devices