Miniature ultrasound device
Company: General Electric
Status: Prototype will be under evaluation by 2005
Despite increasingly sophisticated electronics and huge improvements in image resolution, ultrasound systems today work essentially the same way they have since their introduction in the 1960s. The limitations of this method mean that small systems-and today’s smallest are about half the size of a laptop computer-yield relatively low-resolution images. Kai E. Thomenius, chief technologist for ultrasound and biomedical imaging at GE Global Research, hopes to change that with a tiny revolution in the way ultrasound transducers produce and sense sound waves. His vision: “A doctor reaches into his pocket, pulls out a device, and places it on the carotid artery to see blood flow or on the heart to see its motion.”
The key is replacing the materials now used in the transducers with arrays of microscopic “drumheads” made of silicon. Sound waves produced by the interaction of the ultrasound waves with the body cause these minuscule drums to vibrate, moving electric charges through the silicon. This charge is measured and translated into images. Using silicon rather than traditional piezoelectric materials that require additional electronics to interpret the sound waves means that more electronics can be packed closer together in the transducer, yielding a more compact device. The sensitive silicon drumheads are also more responsive than the most sophisticated piezoelectrics. Moreover, the ability to integrate the transducer with the imaging electronics on silicon offers other advantages, such as the potential for the transducer to send an image wirelessly to a remote display. And while today doctors need to switch transducers to perform different kinds of ultrasound imaging, Thomenius says that a single silicon-based transducer could perform a variety of scans-from 3-D prenatal screening to scans of blood vessels.