A vet practice website is a great place to look to decide if they are right for your new pet or even if you want to re-familiarise yourself with what they offer. While browsing, you might see them advertising ‘digital x-ray’. What is digital x-ray? What is it used for? Is it important that a vet has it?

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What Are X-Rays?

As you probably already know, x-rays are used in both human and veterinary medicine to view inside a patient. But how they work is quite complex, and there’s actually a lot more we can do with x-rays than just looking for broken bones. 

In physics, electromagnetic radiation is the term used to describe invisible waves that carry energy. The most important are visible waves – these allow us to see the world. The other waves are radio waves (used for communications), microwaves (used in microwave ovens and satellite communications), infrared (used for cooking and thermal imaging), ultraviolet waves (used to sterilise medical equipment), x-rays, and gamma waves (also used to sterilise medical equipment, and a key component of nuclear energy). 

We use x-ray waves to produce an x-ray image. This is called radiography. Radiography works like this: 

  • Electrons (tiny particles) are produced by part of an x-ray machine called a cathode. 
  • They are accelerated to the anode
  • On arrival, they react with atoms in the anode, and release energy in the form of x-rays. 
  • These x-rays are directed down towards the object being imaged. 

Because x-rays are very high energy, they can pass through much of a body’s tissue. The denser the tissue, the more these x-rays waves are slowed down or stopped – because bone is very dense, almost all the x-rays are stopped. The x-rays that pass through the body are detected by a sensor or plate underneath the patient. The amount of x-ray radiation detected creates an image – the more x-rays the darker the picture (this is why air is black and bone is white on an x-ray image). 

So What’s Digital X-Ray?

There are two main kinds of x-ray – film and digital.
Film, or conventional, x-ray, was the first form of radiography, invented in the late 1800s by German physicist Wilhelm Röntgen. These radiography machines use photographic film (pretty much the same film found in old cameras) to detect x-rays. Just like how camera film used light waves, the x-ray film receives the x-rays in different amounts depending how much x-rays passed through parts of the body – these cause a chemical reaction on the film that creates an image. Just like camera film, x-rays films must be developed in chemicals before viewing.

Digital x-rays instead utilise sensors that detect the amount of x-ray radiation being passed through the patient – this information is electronically passed to a computer that converts it to an image on a screen. In most veterinary practices, digital x-ray has replaced standard x-ray.

What is Best? Digital or Conventional?

There are many advantages to digital x-ray. The main one is the speed – taking and viewing an x-ray ranges from 2 minutes to almost instant, whereas conventional x-rays must be processed before viewing, taking much longer. This makes diagnosis of disease quicker, especially in an emergency situation where time is a factor. It also allows us to take more x-rays and adjust for errors easier. 

Digital x-rays also require less radiation compared to standard, meaning there is less risk to the patient so we can take more x-rays safely. Cost is important as well. X-ray film is expensive, and while the one-off cost of a digital x-ray machine may be more upfront, there are few consumables needed after this – the sensor plates are reusable, unlike film. Additionally, X-ray film must also be developed using harmful chemicals.

By being computerised, digital x-rays have other advantages. We can store many thousands more x-rays on computer memory, whereas film x-rays must be physically stored. This also makes sending x-rays to clients or other vets much easier, as well as finding old images. Some imaging software allows us to edit and alter x-ray images, making interpretation or labelling easier. They are also less likely to become lost or damaged (provided the computer files are kept safe) – standard x-rays tend to deteriorate over time. 

Digital x-rays have also allowed the development of computed tomography (CT) scans, which are 3D x-rays of whole body parts, providing even greater detail and information on a patient’s body.

Are There Issues?

There aren’t any significant aspects where conventional x-rays are superior, which is likely why they are increasingly uncommon. However, digital x-rays carry all the same risks as conventional, namely the risk of radiation to the patient.

All radiation (from radio waves to gamma) damage living cells by disrupting DNA and causing mutations.  The highest energy radiation waves (x-rays and gamma) have the most energy so penetrate deeper into tissue, causing more damage. This is why these are more dangerous. Every time x-rays pass through a body (either naturally or via radiography), DNA will become damaged. Our bodies have many protective mechanisms to identify and destroy damaged cells, but with enough mutations cells can become cancerous. In short, high doses of radiation can lead to cancer.

However, the risk of cancer due to having an x-ray is very small (one study found x-rays increase the risk of cancer in humans from 0.6% to only 1.8%) and almost always the medical benefit outweighs the risk. In fact, a single human chest x-ray gives the same amount of radiation as only 2.4 days of receiving normal background radiation. 

We must still be aware of these risks to both humans and patient, which is why we keep x-rays to a minimum, keep the doses as low as possible, and protect operators with safety equipment. In almost all cases, the risk of harm from veterinary x-rays is negligible to the patient, regardless of the type of x-ray (and remember that digital x-rays need less radiation anyway).

Final Thoughts

Digital x-rays are an important piece of equipment for any veterinary practice, allowing the diagnosis of a wide range of conditions, monitoring for disease and even assisting with surgery. While conventional radiography provides all of these benefits too, it does so in an inferior way. Skilled vets can still obtain answers with standard x-rays, but they are becoming rarer and rarer. Whether a practice has standard or digital x-ray won’t really affect you as a pet owner, but digital certainly makes our jobs easier!

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