Ultrasound ID: Viable Alternative to RFID for Real-Time Location Systems

Talk about inviting the fox into the henhouse. Wilfred E. Booji, chief technical officer at Sonitor Technologies (Oslo, Norway), explained why some healthcare applications may be better served by active real-time location systems (RTLS) based on ultrasound at RFID Europe 2008 on 1 October in Cambridge, UK. The primary reason to consider USID, Booji told conference attendees, is because of its reliability and accuracy. The technology achieves 100% reliability with room or subroom level accuracy, attaining a resolution of 3 cm, he said. By contrast, radio frequency and infrared systems top out at 3 m. An animation on the company’s Web site shows the relative accuracy of the technologies.

The development of ultrasound RTLS has its origins in a healthcare application. “Company founder Ole B. Hovind, MD, was frustrated by the number of disassociated patient charts and missing mobile equipment in the the hospital where he was practicing,” said Booji. “It was a substantial drain on productivity, and he set out to look into technologies that could locate objects with high accuracy at room-level resolution.” He determined that ultrasound was “near perfect,” according to Booji. In addition to its accuracy, ultrasound does not produce electromagnetic interference and it requires minimal bandwidth.

The technology itself is quite straightforward. Tags attached to a patient or piece of equipment transmit a unique identification signal via ultrasound waves to receivers. They then transmit the signal via an existing local area or wireless network to a central computer, where the tag’s location and the signal’s time of receipt are stored.

“No other system can offer the same level of accuracy and flexibility at this cost point,” crowed Booji. “And because it relies on association events among staff, patients, and equipment, the opportunities in a healthcare setting are limitless,” he added.

Sonitor USID systems are currently installed in more than 30 hospitals in Europe and the United States.