Several stories appeared this month on a study published in the journal Archives of Surgery on the use of RFID tags to detect surgical items left behind in patients. For example, from the LA Times

No sponge left behind
It’s rare, but it happens: surgical staff lose track of an item in a patient. But a new scan could eliminate such gaffes.
By Susan Brink, Times Staff Writer July 24, 2006
…
A new study holds the promise that technology will soon help doctors and nurses, with the wave of a wand, make sure they have taken everything out of a patient’s surgical cavity that they brought in — including the gauze pads that may not show up on a post-surgical X-ray.

In the study, published last week in the journal Archives of Surgery, eight patients undergoing abdominal or pelvic surgery at Stanford University School of Medicine agreed to have surgeons use gauze sponges tagged with radio-frequency identification chips during their procedures. After the operation was complete, and before the patient’s wound was closed, one surgeon turned away while another placed a tagged sponge inside the cavity.

When the first surgeon then passed a hand-held, wand-like scanning device over each patient, he or she could correctly pinpoint the location of the tagged sponge left behind. Within three seconds, the sponges were found and removed.
…

This was one of the use cases we had for a DOD sponsored research project. We encountered two issues: tag size and reading problems. You need tiny passive tags to make this work on the small items that might be left inside a patient. Smaller tags have smaller antennas and are harder to read. A second problem is that RFID signals are attenuated or blocked by metal and liquids. This is a problem since the surgical equipment that might be tagged includes lot of metallic items and, to a first approximation, human bodies are bags of water. I’m not sure if the current generation of RFID is going to provide a general solution for this use case. These kinds of problems is a motivation for developing new tagging technologies like RuBee.

(Spotted on Schneier on Security)

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