Whether you’re a biomedical engineer or a patient interested in learning more about the test you might be receiving, we are here to break down what ultrasound is and how it works! Since we buy, sell, repair, and service ultrasound equipment, we’ve learned a thing or two about the science behind ultrasound probes and what matters most when it comes to improvements in the probe technology. Use this guide to help you understand the technology in ultrasound probes and how it’s used.
What are Ultrasound Probes?
The ultrasound probe, also known as a transducer, is the part of the ultrasound system that touches the patient’s body. It holds the crystals that send and receive the sonic pulses. A transducer is defined as a device that transforms energy from one form to another – like a lightbulb or tv antennae. Similarly, the probe converts electricity into sound and vice versa and then sends the data to the ultrasound machine for it to process and display.
Ultrasound Probe Technology Explained
Ultrasonic imaging is the use of ultrasound waves for diagnostic or therapeutic purposes. Ultrasound machines and probes allow doctors to see problems with organs, tissues, and vessels without needing to make an incision. Unlike other imaging techniques, ultrasound doesn’t use radiation. Because of this, ultrasounds are the preferred method for viewing a baby during pregnancy.
Similar to golf, where the goal is to get the most accurate club that can hit the distance you need, the same can be applied to ultrasound probes. For deeper scans, you need a low frequency. For more superficial scans, you need a high frequency. What you must balance is depth vs. frequency in that you want the clearest, most accurate picture possible. And that’s when you rely on our educated team to guide you towards the best probe for the tests you are performing.
Bandwidth is a primary measurement of an ultrasound transducer’s capabilities. It is the range of frequencies that the probe emits sound waves from the piezoelectric crystals. Ultrasound probe bandwidth can be compared to golf – the further you want to hit, the lower the number of golf club you use. On the other hand, the more accurate you need to be, the higher number of golf club you want to use. For example, for distance, you’d use a 2 Iron versus a 9 Iron. Get the idea?
The field of view is a secondary measurement of an ultrasound transducer’s capabilities, and it is of how large of an area the probe’s image displays while scanning. Linear probes only scan straight down, so their field of view is most likely explained in mm terms. Other probes have a curved array, so their field of view is described by degrees. For the probes that have their field of views described in degrees, think of it as a protractor. If it’s 120 degrees, it will have a field of view of 0-120 degrees on the protractor.
Types of Ultrasound Probes
Probe types are most easily determined by looking at the shape of the probe. Each type of probe has a different specialty, but some can be used for a myriad of tests. Their shape and internal crystal makeup differentiate the way that they display images, and the frequencies that they operate on. We’ll explain some of the most popular ones below in detail.
Linear probes have a flat array and appearance. A linear probe’s piezoelectric crystals are arranged in a linear formation to create a straight sound wave. Linear probes can be applied to a wide variety of uses, such as vascular, breast, thyroid, tendon examinations and more. These probes typically have a rectangular beam with high near-field resolution and run at a high frequency to produce a better image resolution.
An example is the GE 12L!
Convex probes (also called curved linear probes) have a curved array that allows for a wider field of view. The makeup of the piezoelectric crystals in the convex array probe are arranged in a curvilinear fashion. These types of ultrasound probes are complex and can have over 500 elements in their crystal makeup. Typically, these are great for more in-depth examinations. These transducers serve a variety of purposes and are great for vascular, abdominal, OB/GYN, nerve and musculoskeletal examinations. Because of its shape, convex probes are primarily used for abdominal scans due to their wider and deeper view.
An example is the GE 4C-RS!
Endocavitary probes have a much longer probe handle and a “U” shaped lens and array. These probes are used for scanning the inside of the body. Because of the shape, endocavitary probes do not have a great range of depth, but they allow for a wider field than even the convex probes.
An example is the GE RIC5-9-D!
Phased Array/Cardiac Probe
Phased array or cardiac probes have a smaller handle with a square-shaped lens and array. Usually, they scan images of the heart. Phased array probes will have greater depth in order to reach the heart and produce an image. The phased array crystal arrangement is what gives this transducer its name. Phased Array transducers have fewer crystals in them, which means that the crystals fire in phases to create the image seen on the screen.
An example is the GE 4V-D!
Transesophageal (TEE) Probe
TEE probes are cardiac type probes that provide an obstructed image of the heart by inserting the probe into the esophagus, and into the patient’s stomach. These probes move four different directions, and movement is controlled by the handle controls.
An example is the Philips X8-2T!
3D probes function the same as 2D probes, with the exception of a moving array. The array inside the probe moves in a sweeping motion and captures slices of images from different sides. The captured slices are then all put together to produce a 3D still image, or a 4D live image.
An example is the GE RAB6-D!
Need Ultrasound Equipment?
If you need a new or refurbished ultrasound probe or system, give us a call at 866-513-8322 or email us at [email protected] and one of our knowledgeable ultrasound transducer sales specialists will be happy to answer your questions!
About the Author
Brian Gill is Probo Medical’s Vice President of Marketing. He has been in the ultrasound industry since 1999. From sales to service to customer support, he has done everything from circuit board repair and on-site service to networking and PACS, to training clinicians on ultrasound equipment. Through the years, Brian has trained more than 500 clinicians on over 100 different ultrasound machines. Currently, Brian is known as the industry expert in evaluating ultrasounds and training users on all makes and models of ultrasound equipment, this includes consulting with manufacturers with equipment evaluations during all stages of product development.