To say the magnets in today’s M.R.I. (magnetic resonance imaging) scanners are powerful is an understatement. In fact, they have become so powerful they now pose a serious and even deadly danger to patients and hospital staff.
M.R.I. magnets have caused injury or death by attracting various metal objects from a police officer’s pistol (it fired as it hit the magnet), to an oxygen tank brought into the room by staff to provide oxygen to a 6-year-old patient (it killed the child when it struck him in the head), to implanted pace makers which malfunctioned in the patients after their scan.
The surreal accidents are problematic as the number of scanners in the U.S. have increased since 1980 to about 10,000 today, and as magnets have quadrupled in power.
Although the American College of Radiology created safety guidelines in 2002, that were revised last year, the use of the machines is not properly regulated. According to Dr. Emanuel Kanal, the lead author of the guidelines, the best answer is for radiologists themselves to adhere to proper procedures for use.
The escalating number of blunders and the indifference of some scanner operators to voluntary rules, however, suggest it may be necessary to have federal or state laws to regulate M.R.I. scanning.
Dr. Kanal said operations range from "places where safety is paramount" to "bottom-dwellers whose attitude is: ‘As long as I don’t get sued, I’m happy.’ "
Currently, scanner manufacturers like General Electric and Siemens suggest safer room designs to customers. Some even provide safety training for staff. M.R.I. makers cannot require any specific measures be adopted or employed by their customers.
There are a number of ways the scanning rooms could be made safer including architectural changes, new types of metal detectors, and taking precautions to ensure that patients and visitors are not wearing or carrying ferromagnetic metals.
Unfortunately, the roughly 10,000 scanners in the U.S. are not only placed in hospitals, where safety is usually taken seriously, but also in storefront clinics and even mounted on trucks where safety may not be a top priority or possible to the extent necessary to prevent accidents.
While the scanners are somewhat dangerous pieces of equipment, whose magnets can only be shut off by venting freezing and dangerously powerful blasts of liquid helium, most injuries are not caused by machine malfunction but by human error. When performed correctly M.R.I.s are quite safe and, unlike X-Rays, do not pose any radiation-related risk such as cancer.
M.R.I.-related accidents usually involve flying metal objects brought into the room and
attracted to the machine or metal implants in a patient’s body moving and causing harm.
Some reported incidents include an undiagnosed metal sliver in a patient’s eye causing blindness and old pace-makers or artificial metal joints causing injuries or death.
Many incidents, however, go unreported. The FDA’s medical device accident database, records fewer than 100 MRI accidents most of them filed by scanner companies, which learn of them only if the machine is damaged.
For example, on July 13, the Food and Drug Administration (FDA) issued an extensive warning to Richard L. Ernst, President and CEO of Hitachi Medical Systems America, Inc. of Twinsburg, Ohio. (See newsinferno.com for July 27, 2004.)
The warning followed an inspection of Hitachi’s medical device manufacturing facilities in Twinsburg by an FDA investigator on March 16-18 and 24 and April 8, 11 and 12, 2005 with respect to the M.R.I. systems manufactured by Hitachi Medical, Tokyo, Japan.
The above inspection revealed that Hitachi’s devices are misbranded in that the company failed to furnish material or information required under federal reporting regulations.
Specifically, Hitachi had received complaints relating to four separate events for which it failed to submit required reports to the FDA within 30 days of receiving information that the devices may have caused or contributed to a death or serious injury.
While these particular incidents did not involve flying metal objects, they illustrate the reluctance to report malfunctions or accidents on the part of those required to file such reports.
In reality, Dr. John Gosbee, director of patient safety information systems at the Veterans Administration National Patient Safety Center says that "close calls in M.R. centers probably happen once a month."
Dr. Moriel NessAiver, a physicist who teaches M.R.I. safety in Baltimore, has pictures of chairs, polishers and other equipment jammed in scanners on his Web site (www.simplyphysics.com/)