Guide to Ultrasound Transducer Types: How to Choose the Best Ultrasound Probe

Article Main Topics:

1. Ultrasound Transducer Types
2. Linear Transducers
3. Convex Transducers
4. Phased Array Transducers
5. Pencil Transducers
6. Endocavitary Transducers
7. Tips to Follow When Buying an Ultrasound Transducer
8. How to Treat Your Transducer?
9. Your Most Common Questions – FAQ

This article has been updated 02-02-2025

To utilize the full potential of your ultrasound system, you need the right accessories.

Therefore, the correct ultrasound transducer – also called piezoelectric transducer – types are the key to the performance of your ultrasound.

In this blog post, we explain the different ultrasound transducer types.

And determine the types of examinations you can use them for.

In the end, we will offer some good points you should keep in mind when you are purchasing ultrasound transducers. When you are done reading, you will be confident in the ultrasound probe differences.

And, you will be able to easily answer the question: “How do I choose an ultrasound probe?”.

But first of all:

What is an ultrasound transducer and what does it do?

An piezoelectric transducer, also called a probe, is a device that produces high-frequency sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create an image called sonogram. There are many ultrasound probe types.

Moreover, the essential element of each ultrasound transducer is a piezoelectric crystal.

It serves to generate as well as receive ultrasound waves. Sadly, the medical imaging industry was using the same piezoelectric material for over 40 years.

Up until a few years ago.

Then, a new type of crystal material and ultrasound probe technology appeared.

That meant a dramatic improvement in image quality in the different types of ultrasound transducers.

Ultrasound Transducer Types – What are the ultrasound probe differences?

We get it – it can be difficult to know exactly which ultrasound probe to use.
Let us explain it a little deeper.

You can find many types of ultrasound transducers in different shapes, sizes, and with diverse features, as well as for 2D, 3D ultrasound or 4D ultrasound. That is because you need different specifications for maintaining image quality across different parts of the body.

Ultrasound transducers can be either passed over the surface of the body – external transducers. Like with a convex transducer. Or it can be inserted into an orifice, such as the rectum or vagina – these are internal transducers.

Any more ultrasound probe differences?

Yes!

The ultrasound probes types differ in construction based on:

• Piezoelectric crystal arrangement
• Aperture (footprint)
• Frequency

Let us go through one at a time.

Footprint also called the aperture, is the part of the ultrasound probe that is in contact with the body and comes in different shapes and sizes. The footprint is linked to the piezoelectric crystal arrangement, for instance, with linear and convex probes.

The piezoelectric crystal arrangement is the part that obtains the image. Therefore, it affects the footprint but also decides the shape of the ultrasound beam.

Frequency means the frequency of the sound waves emitted from the probe. Generally, higher frequencies offer better image quality, but not as deep penetration compared to lower frequencies.

But then, what are the different types of transducers in ultrasound?

Below we list the three most common ultrasound transducer types – linear, convex (standard or micro-convex), and phased array. Furthermore, we included other ultrasound transducer types that are available on the market, those are pencil and endocavitary probes.

So, how to choose the right ultrasound probe?

Because there are many different ultrasound probe types and uses, it can be tricky to find the right one for your needs.

This is because choosing the right ultrasound probe depends on the medical application you need it for. Factors to consider include the transducer’s ultrasound frequency range, footprint, and the specific area of the body being examined.

For example, linear transducers are ideal for vascular imaging, while the convex transducer is suited for abdominal exams. And phased array probes are commonly used for cardiac imaging.

We dive deeper into the different probe applications when discussing specific types of ultrasound probes below. Choosing the right probe for your application is crucial for the image resolution in ultrasound.

Linear Transducers

So, what features are typical for the linear probe?

Firstly, the piezoelectric crystal arrangement is linear, the shape of the beam is rectangular, and the near-field resolution is good.

Secondly, the footprint, ultrasound frequency range, and applications of the linear transducer depend on whether the product is for 2D ultrasound imaging or 3D ultrasound imaging.

Furthermore, the linear probe for 2D imaging has a wide footprint and its central frequency is 2.5Mhz – 12Mhz.

You can use the linear transducer ultrasound for various applications, for instance:

• Vascular examination
• Venipuncture, blood vessel visualization
• Breast
• Small parts
• Thyroid
• Tendon, arthrogenous
• Intraoperative, laparoscopy
• The thickness measurement of body fat and musculus for daily health care check and locomotive syndrome check
• Photoacoustic imaging, ultrasonic velocity change imaging

The linear transducer for 3D imaging has a wide footprint and a central frequency of 7.5Mhz – 11Mhz.

What can you use this linear transducer for?

• Breast
• Thyroid
• Arteria carotis of vascular application

You can also get 4D ultrasound machines with 4D probes. The difference from 3D to 4D, however, is not huge.

In our stock, we offer linear transducers from top brands, such as:

Convex Transducers (Also: Curved or Curvilinear probe)

Another of the ultrasound transducer types is the convex probe.

Also called the curved transducer because the piezoelectric crystal arrangement is curvilinear. Moreover, the beam shape is convex and the transducer is good for in-depth examinations.

Even though the image resolution decreases when the depth increases.

The footprint, frequency, and applications also depend on whether the curvilinear probe is for 2D or 3D imaging.

For example, the convex transducer for 2D imaging has a wide footprint and its central frequency is 2.5MHz – 7.5MHz.

You can use convex probes for examinations such as:

• Abdominal scanning
• Vascular
• Nerve
• Musculoskeletal ultrasound
• OB/GYN
• Transvaginal and transrectal
• Diagnosis of organs

The convex transducer for 3D imaging has a wide field of view and a central frequency of 3.5MHz – 6.5MHz.

You can use it for abdominal examinations.

In addition to convex probes, there is a subtype called microconvex transducer. The microconvex transducer has a much smaller footprint and are typically used by physicians in neonatal and pediatric applications.

From top ultrasound manufacturers, you can get convex transducers such as:

Phased Array Transducers

The phased array transducer is named after its piezoelectric crystal arrangement, known as a phased array, and it is the most commonly used crystal type.

The phased array transducer has a small footprint and operates at a low frequency (with a central frequency range of 2 MHz – 7.5 MHz)

The beam point is narrow but it expands depending on the applied frequency.

Furthermore, the beam shape is almost triangular and the near-field resolution is poor.

What can you use the phased array transducer for?

• Cardiac ultrasound examinations, including Transesophagealexaminations
• Abdominal scanning
• Brain examinations

In our current stock, we have these – and more – phased array probes available:

Below we introduce other common ultrasound transducer types:

Pencil Transducers

Pencil probes, also called CW Doppler probes, you can use to measure blood flow and the speed of sound in blood.

Furthermore, pencil transducers have a small footprint and use low frequencies, typically ranging from 2 MHz to 8 MHz.

Endocavitary Transducers

Furthermore, on the list of ultrasound transducer types, there are endocavitary probes.

Endocavitary probes provide the opportunity to perform internal examinations of the patient. Therefore, they are designed to fit specific body orifices.

Endocavitary transducers include endovaginal, endorectal, and endocavity probes (for example, the Philips C10-4ec endocavity probe below).

Typically, they have small footprints, and the frequency varies in the range of 3.5 MHz to 11.5 MHz.

There are also the transesophageal echocardiography (TEE probe) and the transesophageal probe (TEE). As the previously mentioned probes, it has a small footprint and is used for internal examinations.

It is often employed in cardiology to obtain a better image of the heart through the oesophagus. The frequency is middle, in the range of 3Mhz – 10Mhz.

Endocavitary and pencil probes ready in our stock:

Moreover, there are several probes designed for surgical use, such as laparoscopic probes.

Overview of the Different Types of Ultrasound Transducers

To get a quick overview of the different ultrasound transducer types and their applications, see the table below. You can also go to our Ultrasound Probes for Sale page and browse through our inventory.

Tips to Follow When Buying an Ultrasound Transducer

Now, you should be aware of the most common ultrasound transducer types. It can be a jungle to figure out the right ultrasound transducer types and frequency.

Therefore, we have a few tips to follow when purchasing ultrasound transducers:

• Make sure to double-check that the ultrasound probe you are about to buy is compatible with the system you own – you can use a probe guide, or ask our sales team.
• Penetration depth is better at a low frequency (between 2.5 and 7.5Mhz) but a disadvantage of the low frequency is a lower image quality.
• The higher the frequency (above 7.5Mhz), the lower is the depth of penetration, however, you get better quality images close to the surface (7.5MHz = 20 cm).

Be cautious:

• A black line on the screen of the ultrasound system will most likely mean that the transducer has a dead crystal inside.
• A shadow on the screen of the ultrasound system could indicate a weak crystal inside the transducer that does not produce the necessary vibration.

How to Treat Your Ultrasound Transducer?

Finally, remember that the transducer is a very important, and also a very expensive element of an ultrasound. Therefore, after you have purchased it, remember that no matter the ultrasound transducer type, you should use it with caution, which means:

• Do not throw, drop, or knock the transducer
• Be careful not to damage the duct of the transducer
• Wipe the gel from the transducer after each use
• Do not sluice with alcohol-based confections

To learn more about how to protect your ultrasound probes and what the most common defects are, check our blog post that explains this topic in more depth.

We hope that after reading this article, you have a clear image of ultrasound transducer types. And that you will be more prepared the next time you are purchasing ultrasound scan probes.

If you have any more questions about ultrasound transducers for sale or used ultrasound machines, do not hesitate to contact our sales department at [email protected] or via phone +45 96 886 500 (International) or (855) 463-3727 (Americas).

Also, check our inventory of ultrasound machine parts.

What is next?

Done reading about ultrasound transducer types? You can sign up below to receive an e-book: ‘How to pick your next ultrasound’ and become part of our ultrasound mail course.

This course will guide you through themes related to your next ultrasound purchase.