How to use a Veterinary X-Ray Technique chart

Mastering Veterinary X-Ray Techniques

Quality diagnostics are the foundation of a confident patient diagnosis. It’s no surprise that veterinary radiography is one of the most commonly used diagnostic tools when confirming (or ruling out) a patient diagnosis.

Although the terms “x-ray” and “diagnostic image” are often used interchangeably, to rule an image as “diagnostic”, it should display quality contrast and dynamic range and avoid any artifacts.

To achieve these characteristics, let’s start with the foundation of what produces a quality diagnostic image: a technique chart.

The Purpose of a Technique Chart for Veterinary Radiography

A digital radiography technique chart is a standard guide to producing the optimum exposure for a diagnostic image.

Put another way, it’s a table of predetermined exposure settings that, when used accurately, ensure consistent image quality and patient exposure.

A reliable, user-friendly chart is important for obtaining clear diagnostic imagery with consistent radiographic density and contrast.

Why do Technique Charts for Veterinary Digital Imagery Matter?

Patient care and wellbeing is always top priority and proper treatment starts with a confident diagnosis.

Veterinarians and Veterinary Specialists rely on quality diagnostic images to rule out suspected diagnoses and confirm findings to develop an accurate treatment plan.

With many veterinary practices upgrading to quality veterinary X-ray software, there’s a little more forgiveness in under/overexposed images (with veterinary X-ray technology advancements, we can manipulate image contrast); however, not all exposure imperfections can be corrected.

Having a precise image from the start is crucial to a proper evaluation.

What Factors Make Up a Technique Chart?

Let’s break it down…

Most technique charts are segmented anatomically by thorax (chest), abdomen, spine, and extremities (arms, legs, tail) since each area varies in density. The measurement of the anatomical body part will determine the exposure settings.

What exactly are exposure settings?

Exposure settings include:

· kVp (kilovoltage peak), which controls the penetrating power of the x-ray beam (or how energetic the x-rays are)

· mAs (milliampere-seconds), which controls the number of x-rays.

Typically, the higher the mAs, the better the image quality; however, it’s important to be judicious with these settings because they can also contribute to the patient's radiation dose.

How to Use a Technique Chart for Veterinary Digital X-Rays

It all starts with accurate measurements. Begin by using a set of calipers to measure the anatomical part of the patient you’ll be radiographing.

Tip: for best results, measure the patient in the position they’ll be in during the radiograph (ex: right lateral recumbency) and measure from the point of x-ray entrance to exit.

Once you’ve got your measurement (in cm), consult the technique chart to determine the kVp and mAs to set the X-ray generator.

Depending on your veterinary hospital’s X-ray system setup, you may also need to determine whether the X-ray cassette needs to be placed on the tabletop or in the bucky tray (also known as the “film tray”).

You can place your technique chart aside and manipulate your tube head and lighting in preparation for your image.

Tip: Remember, the tube head may need to be raised if the cassette is on the table top or lowered if it’s in the Bucky tray.

Remember to place a left/right marker to indicate patient positioning (for example, if the patient is in right lateral recumbency, an “R” label should be included on the image).

Once you’ve confirmed your settings are correct, the cassette and tube head are in the correct position, the label is placed, and the patient is in position, you’re ready to capture your diagnostic image!

Making Adjustments to Exposure Factors

Sometimes adjustments are necessary for a clear visual of injuries or problem areas. Here are a few tips to consider before your retake:

  • If the initial radiograph is too light, try increasing the kVP by 15% (mAs remain the same)

  • If the initial radiograph is too dark, try decreasing the mAs by 15% (mAs remain the same)

Want to learn more?

For more tips on achieving quality diagnostic veterinary images, check out these articles below:

Warnings!

  • Don’t participate in x-ray diagnostic imaging if you’re pregnant to avoid harmful radiation to your little one.

  • Avoid using old, run-down, or defective protective gear. If cracks, tears, or fraying appear, replace your veterinary radiology protective supplies.   

Additional Resources:

· Merck Veterinary Manual: Radiography of Animals