The Ultrasound Probe developed by Interson Corp., Pleasanton, Calif., has the capabilities of a standard probe without the six-figure price tag. The device is a complete ultrasound imaging system built into a small probe weighing only 7.5 ounces. Doctors purchase the probe then download software to an exam-room computer. The unit plugs into the computer's USB port which provides the 0.5 A to operate the probe. The device does not require the dedicated detection and display hardware the more expensive systems need. Further, image quality increases by eliminating the analog signal noise from traveling through a cable to be processed in the system. An added bonus is that ultrasounds no longer need to be performed by specialists or require visits to a different facility.

“The most difficult challenge was finding motors that could run on the 5V from the USB cables,” says Roman Solek, President of Interson. Then, the company needed a variety of motor sizes available for the different probes.

The company chose model 16 and 22 A-max motors from Maxon Precision Motors Inc., Fall River, Mass. “The units combine a low-power motor with a position encoder.”

Maxon's patented rhombic moving coil design provides for longer life than competitive motors. Moving coil, or ironless, motors do not use an iron core with copper wire wound around it as the basis for the rotor. Instead, the iron core is removed altogether and it uses a free standing copper coil. This design offers significant advantages as compared to conventional DC motors, including low electrical noise, fast acceleration, and high efficiencies. Another important spec: an ironless rotor allows for zero cogging, which means simple, accurate control.

The ultrasound probe comes in 3.5, 5.0, 7.5, and 12 MHz versions for use in common ultrasound applications. It is currently available in veterinary offices to assist with cystocentesis, intravenous or arterial catheters, clinical judgments regarding cardiac contractility and chamber size, and to diagnose free abdominal or thoracic fluids in trauma cases. A similar probe for use in doctors' offices is pending FDA approval.