You have your ultrasound machine and now need to decide on a probe, what are the options?

Probes and Transducers are often used interchangeably. Not all probes are the same, and it might be challenging to find the one that is right for you. Here are some helpful hints for you to consider.

1. Frequency of the Ultrasound Probe

Ultrasound probes are made with materials called piezoelectric, which are usually made from ceramic crystal. When an electric field is supplied, the ceramic crystal piezoelectric make sound waves. This process also works in reverse and produces an electric field when a sound wave hits.

When used during an ultrasound, a probe sends sound waves into the body and generates electrical signals. The speed and distance at which this is done is measured in megahertz. This is why when you are buying an ultrasound probe, you will see a number followed by MHz.

Besides speed and distance however, these interactions also affect the frequency:

  • Reflection
  • Refraction
  • Scatter
  • Attenuation
  • Transmission

The frequency range you choose will affect how well you can see an image produced by the sound waves inside the body. Ultrasound probes that have a higher frequency, which is anywhere from 12 to 20 MHz, generally produce an image with higher resolution.

However, because probes with higher frequency don’t penetrate as well, they are usually only used for organs that are closer to the surface of the body. Ultrasound probes with a lower frequency that ranges from 1 to 5 MHz have better penetration but do not produce high resolution images.

2. Type of Ultrasound Probe Array

The part of the ultrasound probe that comes into contact with the patient is an array. It is usually a grayish rubber material that covers the ceramic crystal piezoelectric. Arrays come in four different formats with each format producing a specific type of image.

The four array formats include:

  • Linear: produces high quality rectangular-shaped images
  • Sector: produces slice-of-pie-shaped images of larger organs
  • Phased: produces triangular-shaped images and is often used on the heart and brain
  • Curved or Convex: combines benefits of both linear and sector formats

The format you use will largely depend on what shape of image you need to see, along with what organs you are viewing. Along with the format, the length of array is also important as the longer the array, the more sections of the structure you will be able to see. For smaller organs that need to appear larger on the screen, a shorter array is optimal.

3. Design of Ultrasound Probe

Ultrasound probes also come in a few different designs, and as with each of the other factors, different probe designs are used in specific circumstances. When the array is on the far end of the probe, it is considered a traditional grip intended to be placed on top of a body surface and held in the palm of the hand. Rectal proves are

Rectal probes are the most obvious exception in veterinary medicine, where the array is oriented along the side of the probe and the cable exits at the rear. CLi transducers are an interesting hybrid design—they incorporate the array of our large trans-abdominal probe into a rectal grip. This unique design allows the probe to be used for both applications.

Tips for Buying an Ultrasound Probe

Remember  to purchase an ultrasound probe that is compatible with your machine and it  handle with care, never  cleaning it with fluids that contain alcohol.