Implants Trigger Airport Metal Detectors

Researchers at Beth Israel Deaconess Medical Center (BIDMC; Boston, MA, USA) examined 129 volunteers with a total of 149 implants who walked through a three-zone metal detector used at commercial airports. The detector was programmed at both low and high levels, with sensitivities equivalent to United States Transportation Security Administration (TSA; Arlington, VA, USA) settings. Fifty-seven of the 149 implants were detected at the low-sensitivity setting, and 77 were detected at the high-sensitivity level.

The researchers found more than half of all orthopedic implants may be detected by metal detectors, and 90% of total knee replacements and all total hip replacements were detected, whether they were unilateral or bilateral. On the other hand, plates, screws, intramedullary nails, and wires are rarely detected. Cobalt-chromium and titanium implants were much more likely to be detected than stainless steel implants.

The researchers also found that lower-extremity implants were detected 10 times more often than upper-extremity and 11 times more than spine implants. Upper-extremity prostheses, such as total shoulder replacements, total wrist replacements, and radial head replacements, were not detected. The study was published in the April 2007 issue of the Journal of Bone and Joint Surgery.

"Our results will aid surgeons in counseling patients regarding their implants and security agencies by identifying which medical devices commonly set off metal detectors,” said lead author Edward K. Rodriguez, M.D.

The TSA website offers the following suggestions: (1) It is recommended (but not required) that the security officer is advised if an individual has an implanted medical device or metal implant and where that implant is located. (2) If a physician has indicated that someone should not go through the metal detector or be hand-wanded because it could affect the functionality or the magnetic calibration of the individual's device, the security officer should be asked for a pat-down inspection instead.


Related Links:
Beth Israel Deaconess Medical Center
U.S. Transportation Security Administration