What is an Ultrasound Transducer?

An ultrasound transducer is a medical device which is used with an ultrasound machine to generate images of the inside of the human body. When an ultrasound imaging study is performed, the technician applies the transducer to the area of interest, periodically moving it around and changing the angle to get a complete view. The transducer both sends and receives sound waves, and the ultrasound machine uses the data collected by the transducer to create an image.
Ultrasound transducers are also known as ultrasound probes. They are made with piezoelectric crystals, crystals with some unique properties which make them ideal for ultrasound applications. When the operator wants to transmit sound waves, he or she uses the ultrasound machine to generate an electrical charge which deforms the shape of the crystals. As the crystals change shape, they emit sound waves which penetrate the area of the body where the ultrasound transducer is applied.
When the sound waves hit the body, they bounce back and hit the transducer again. The pressure of the returning sound waves causes the crystals to change shape again, creating an electrical charge which is transmitted to the ultrasound machine. The machine can interpret the information provided by this charge to create an image of what is going on inside the body.
Operators can adjust the duration, frequency, and amplitude of the sound waves they emit with an ultrasound transducer by manipulating settings on the ultrasound machine. A number of different shapes and sizes of ultrasound transducer are available for specific tasks. Some, for example, operate in a very wide field which can be used to create a large and generalized image, while others are smaller and narrower for imaging in more isolated regions of the body. Some ultrasound probes are designed to be inserted into the body through the throat, vagina, or anus so that the sound waves have less barriers to pass through, for use in imaging studies where better image quality is desired.
Ultrasonography can be a very valuable tool in medical treatment and diagnosis. Using an ultrasound machine, doctors can acquire images of what is going on inside the body without the need for invasive procedures like exploratory surgery. Ultrasound imaging can also be used to monitor things like the process of a pregnancy, or the health of the heart. Advanced ultrasound transducer designs have allowed doctors to create things like three dimensional ultrasound images, in which an array of transducers is used to construct an image which includes multiple angles, creating a more complete picture.