In recent years, veterinarians have had a lot to choose from in terms of CT system sizes, technology, combinations, and price points.
While it’s good to have options, it can also feel like “information overload” trying to choose the best machine for an individual practice. The following information may help with this important decision…
Conventional CT
Traditional, fan-beam-style CT scanners were the norm for a long time. And they still serve a valuable purpose. A fan-beam model is a good all-around option, especially for hospitals that see all different sizes of patients including large dogs.
Fan-beam CT machines work by taking image “slices” (cross-sectional images) that are picked up by an array of detectors. Then the patient is advanced further into the gantry (entryway) and another slice is taken—and so on until the area of interest has been fully imaged.
Slice Counts
Advances in fan-beam technology include systems that image multiple slices at once. Instead of a single slice, this could mean 4, 8, 16, 32, or even 64 slices at a time. These multidetector CT scanners have the advantage of being faster than a single-slice machine.
Although slice thickness factors in, as you can imagine, shooting a larger area (i.e., multiple slices) at once means the study takes less time. In some cases, this can reduce anesthesia or sedation requirements. But chemical restraint may still be needed for areas in which motion artifact is a bigger confounding factor, such as respiratory movements during lung studies.
As you can probably also imagine, the price of the machine goes up as the slice count increases.
Slice Thickness
There are pros and cons to both thinner and thicker image slices. Thinner slices allow for the acquisition of more details. Thicker slices allow for faster study times.
Helical or Spiral Scanners
Originally, the patient would be advanced into the machine, then stopped while the first image slice is obtained, then advanced a little further, and so on…
With helical models, the patient is continuously advanced without stopping. This results in the x-ray tube head moving in a spiral motion around the patient.
This can mean shorter study times. Helical models can also have great image quality, including 3D renderings.
Cone-beam Technology
Cone-beam CT is a newer, increasingly popular option. Instead of the images being captured on a narrow array of detectors like fan-beam technology, they are captured on a wider flat panel detector similar to those used for regular X-ray machines.
Veterinary cone-beam CT is a nice option because of the smaller footprint and lower price point. They’re also ideal for certain studies, like the skull, extremities, and some musculoskeletal views.
However, these small machines don’t accommodate larger patients or offer as much contrast and detail for soft tissue studies. And they may be more susceptible to motion artifact.
Portable CT Machines
Battery-powered, portable CT scanners are also available. They might be advantageous for busy hospitals with limited space, or for any practitioners who need to move their machine to the patient.
Many of these machines use standard electrical outlets for power or for battery charging, which is convenient compared to higher-powered machines. Some also have built-in shielding, which can decrease the requirement for lead-lined walls.
A practice should check the specifications for the specific machine they are purchasing.
Combo Machines
Some models offer combinations of CT, fluoroscopy, and even standard digital x-rays all in one. But are they worth it?
It depends. If there is a significant price advantage—and the image quality is great for ALL modalities—a combo could be a practical, space-saving option.
If one or both of these requirements aren’t met, a veterinary practice might find it’s better for them to focus on one modality at a time rather than purchasing a combination machine. It’s also important to consider whether there is a potential “bottleneck” in scheduling—for example, team members waiting to do a CT scan while someone else finishes radiographs.
Veterinary Radiologist Consultations
It’s exciting that CT technology is becoming more widely available and even used by some general practitioners. However, there is a large learning curve for any new imaging modality a practice adopts. Veterinary CT is no exception.
Specialists exist for a reason. Veterinary radiologists have significantly more knowledge and experience with advanced imaging modalities. A consultation with a radiologist can help with everything from pre-purchase planning (which model to purchase, requirements to set it up at a clinic, maintenance cost considerations, etc.) to doing teleradiology consultations on the images obtained from a CT scanner.
For teleradiology consultations, ask ahead of time if the radiologist has any specific requirements for the type of machine used, the settings, etc.
Investing In the Right Machine
As time goes on and more veterinary practices show an interest in CT scanners, there’s no doubt that new technology and options will be developed.
Decision makers at each practice must perform due diligence and talk to experts (veterinary radiologists, business/financial consultants, and state regulations for radiation safety) prior to purchasing and using a CT system, to ensure the machine they purchase is a good fit for them.
With that in mind, it’s an exciting time in veterinary medicine, as practitioners have yet another option for providing advanced patient care at their practice.
Written by: Dr. Tammy Powell, DVM
