The portion of the sound head that produces the sound wave is referred to as the ERA-the effective radiating area. The ERA is always smaller than the transducer area, but the closer the ERA and transducer surface areas are, the better the penetration and accuracy of the therapeutic dose.
An example of a good ERA is the following: Surface area of the ultrasound head is 7 cm2 and the ERA is 5 cm2.
An example of a poor ERA is the following: The ultrasound head is 7 cm2, and the ERA is 2.5 cm2.
Yes, while most of the Ultrasound devices will have their Effective Radiating Area listed, it is a value that can be independently ascertained (mostly by trained technicians) by determining the portion of the transducer head that is actually producing the sound waves. The American Food and Drug Administration (FDA) guidelines regulate the accuracy of the output power produced by Ultrasound units manufactured or sold in the United States, permitting a ±20% error band. They require that manufacturers report an error band for ERA but stop short of dictating what is an acceptable percentage of error. Most manufacturers report a ±20% or 25% error for ERA while a few manufacturers report an actual measured ERA value for each transducer.
0
0