With almost all types of veterinary diagnostic imagery, the effort is in the prep work!

That means getting the correct measurements, exposure settings, and positioning off the bat leads to the best results.

In a previous blog, we discussed why we get underexposed X-rays and how to identify them.

However, it’s easy to overcompensate when adjusting exposure settings and get the opposite effect: overexposed X-rays.

With proper knowledge, practice, and technique, getting a well-balanced exposure rate is simple!

What is an Overexposed X-Ray?

Overexposed X-rays are a result of X-ray settings being too high (using an increased kVp and mAs). This causes too much energy build up in the primary beam.

With excessive energy build-up, the patient absorbs little energy, and an overdose of radiation is absorbed into the detector. A detector starts white and darkens as it’s met with radiation.

As a result, the image will be overexposed (or too dark) to be considered diagnostic. The X-rays are essentially “burning” the plate, causing significant internal structures and tissues to appear less visible.

As you can imagine, this inhibits a clear interpretation by the Veterinarian or Veterinary Specialist and delays a proper diagnosis and treatment.

How Will I Know the X-Ray is Overexposed?

It’s not hard to identify veterinary X-rays that have been overexposed.

Here are a few characteristics that will stand out:

• · Image has a darkened appearance

• · Poor visibility of internal structures

• · Blur or distortion

• · Scatter Radiation (reduces image contrast and clarity as a result of the x-ray changing direction –“scattering” - when it meets the patient)

To be appropriately interpreted by a Veterinarian or Veterinary Specialist, you’ll likely need a retake to visualize lesions, growths, or other abnormalities clearly.

Why is My X-ray overexposed?

Capturing an overexposed image is frustrating. Now that we’re pretty clear on what they look like, let’s talk about what may have caused it:

• · Incorrect kVp or mAs settings (if settings appear correct, consider re-measuring to confirm measurements were accurate)

• · Forgetting to move the x-ray tube head to the correct position (if it’s too close to the cassette, it’s easy to cause overexposure)

• · Possible technical error

If I Need a Retake, How Can I Avoid Another Overexposed X-Ray?

Here are a few easy-to-follow tips to avoid overexposed X-rays with your next image:

1. Correctly measure the anatomical part of the patient you’ll be radiographing using a set of calipers (remember, it’s best to measure in the position they’ll be in for the image)

2. Confirm X-ray settings using your veterinary X-ray technique chart

3. Ensure the x-ray tube head is in the correct position (raised if the plate is on the tabletop or lowered if it’s in the bucky tray)

4. Don’t forget to collimate (helps to reduce scatter radiation for a better image quality)

For best results, use computed radiography software tools to reduce artifacts, distortion, and scatter radiation (not to mention hassle-free transfers of DICOM or JPEG images for diagnostic review).

The Quick Take Away

If we think of X-ray exposure like a toaster, when the toaster produces too much energy, we’re left with toast that’s burnt to a crisp.

Just as we’d need to decrease the time on our toaster for a better breakfast, the x-ray settings will need to be reduced on the machine for a balanced diagnostic image.

We want to aim for images that have:

· Sharpness (in focus, clear, and distinct)

· Visual characteristics of density and contrast (adequate representation of tissue density)

· Clear visualization of internal structures

· No distortion or artifacts (no patient motion, technical errors, unnecessary objects, etc.)

Avoid the hassle of retakes by putting effort into the prep work—accurate measuring, exposure settings, and positioning—and getting back to what truly matters to you and your patients.