As medics move the device along a patient's arm or leg, the transducer emits a thin acoustical beam, about the size of pencil lead, into the reflector. Then the reflector directs the ultrasonic waves into the patient's skin at a slight angle. The device can determine the direction of blood flow to distinguish arteries (which carry blood away from the heart) from veins (which carry blood to the heart). Once the device detects a vein, an alarm is triggered, and medics insert the needle.
The vein finder has proved highly effective in initial tests on phantom tissue, a model that simulates human tissue and blood vessels. Researchers have now begun adapting the device for human use.
Developing the user-friendly vein finder has been a deceptively complex task.
"One reason it's so challenging is that we're using very simple components to keep costs down," notes Francois Guillot, a research engineer in the School of Mechanical Engineering.
Unlike large ultrasound systems used by hospitals for general blood-flow studies, the vein finder is targeting a very small area of the body. "That means the acoustical beam has to be smaller," says Jim Larsen, a research engineer in EOSL. Another complication is that only a small amount of energy, about 1/10,000 of transmitted waves, scatters off the vein.
"So you're limited in how much energy you can put in and how much you can pick up," he adds. "Cost, size and power issues restrict us to using a single sensor, which limits the type of signal processing we can do to eliminate the scattering effects."
Once the system is successfully adapted for humans, data processing and electronics will be miniaturized in a prototype for field-testing. The researchers envision the final produc
Source:Georgia Institute of Technology Research News