Written by: Eric Hoffmann - UXR Inc
The cost of implementing Direct Radiograph (DR) solutions for the typical veterinary practice has come down to a point where most practices can now afford and justify the introduction of a DR solution in their practice.
The challenge facing most veterinary practitioners in their decision-making is to sift through the vast amount of information related to the options being presented in making this choice, and identify those considerations (technology, performance, longevity, science, etc.) which are applicable in their (Veterinary Practice) real world and will truly deliver tangible advantages that will inure to the benefits of their practices.
The goal of this paper is to put into perspective where the reality for veterinary practices lies, and enable prospective buyers of DR technology to simplify their decision-making process.
The areas of concern and confusion typically center around,
Direct versus Indirect Detectors,
Choice of Scintillator Material,
Life Expectancy of different detector types,
Technique & Dose – hypothetical versus actual,
What constitutes DR?
Details, details, details.
1 - Direct versus Indirect
A direct detector has the X-Ray Beam acting directly on the Selenium or Silicon array of pixels, resulting in quicker reaction time (milliseconds), but note that the heart of the device is directly exposed to Radiation and this can have a long-term negative, or adverse, impact on the device’s life expectancy.
An indirect device has a scintillator, normally Cesium or Gadolinium Oxysulfide (Gadox), which converts the X-Ray Beam to Light, and then is picked up by the array and an image is produced from this.
Most detectors being offered and used in Veterinary Medicine are of the indirect type; that is to say with scintillators. Which leads us to…
2 – Cesium vs. Gadox
Cesium is touted as being quicker, and more sensitive, than Gadox; let me be clear - this is absolutely scientifically accurate.
However, most often this does not translate into any real, or tangible benefits for the user – how can this be then?
In most instances, we see a DR panel being installed into an existing or new X-Ray system, continuing to use the default (film) techniques. This means, simply, that any inherent higher level of sensitivity of Cesium vs. Gadox is being entirely overlooked. Net result? There is no reduction in dose which the operators are subjected to.
3 – Benefitting from lower dose
The logical extension to the contradiction of promise versus delivered in point #2 above is that the vendor delivering the Cesium-equipped detector should be configuring a lower technique chart (either paper or in the unit’s Anatomical Programming Console) to only deliver as much dose as the detector requires, improving the safety for the X-Ray technicians. This rarely happens in the real world.
The counter argument will be that a good detector has AED (Automatic Exposure Detection) built into it, so the detector only takes what it requires to produce an excellent image. This is not an acceptable answer, as the X-Ray system is still putting out more dose than is required and the technicians are still being exposed to the traditional, higher level of dose.
So, the conclusion, there is often no real-world benefit of implementing systems with Cesium vs Gadox scintillators.
4 – Life Expectancy
I believe we can all agree that the less radiation anything is exposed to the better, whether that be human tissue or a Detector. We have previously stated that the Indirect Detector, with a filter (of sorts) function being provided by the Scintillator, is exposed to less dose that the Direct Detector.
5 - What constitutes DR?
Veterinary prospects will often be bombarded with statement such as “we offer only Real DR’ or some other such statement.
The actual definition of a Direct Radiography device is one where there is no intervening step or process is involved in converting the reception of X-Ray to producing an image; simply put, there are no cassettes to process. Less time, higher throughput.
What is the mainstream veterinary DR population made up of?
A good reference article was published on animalinsides.com (CCD is DR, Clearing Up Some Confusion, August 2012) by Matt Wright, DVM.
6 – Details, Details, Details
All this being said, a good image is very subjective. Decision-making complexity is directly proportional to the level of the investment required; while DR has come down in price and is more affordable than it has ever been, it is still a chunk of change.
Do your homework…consider factors such as pixel pitch, image processing software, quality of your X-Ray device (this is often the weakest link in the implementing DR process) when considering a Retrofit option, credibility, technical expertise, and support offered by your vendor.
Don’t get distracted or misled into the belief that scientific absolutes always translate into any form of real benefit to the purchaser or user.
We hope this helps you in your quest for the right DR solution for your practice. Good, well implemented DR is a joy and you’re gonna love it! Enjoy!