Purchasing a veterinary CCD based DR machine can be difficult. The main problem we encounter during our prepurchase consultations is how to sort through the vast number of machines on the market. By our estimate there are no fewer than 18 different models of CCD camera on the market and every year there are more and more. Furthermore, the vendor marketing materials would have you believe that all of the cameras on the market are excellent. So why do some cost so much and others cost so little? The trick is knowing a little bit about CCD cameras and organizing your research. 

Keep this in mind when shopping for a CCD machine: CCD based DR machines utilize a CCD camera to generate an image.  The first key to image quality (in all digital cameras) lies in the camera used to generate an image and the softare used to process an image. Think about it. Your cell phone has a digital camera in it but you dont expect the images to turn out like a $10,000 SLR with fancy lenses. With all cameras, you get what you pay for.

Step 1: Megapixels -  The first term you will hear vendors talking about is the "megapixel rating" of the camera. The megapixel rating is simply the number of pixels in the image. In theory, if you have more pixels, you can increase the resolution of your image. In practice, however, there are so many factors that affect image quality you simply cannot shop based on the megapixel rating of a camera.

Another issue with images from cameras with high megapixel ratings is that the images are enormous (>20mb). This makes teleradiology very difficult.

The bottom line is that higher megapixel cameras tend to perform better but you have to look at the whole package (lens, detector, processing) and some lower megapixel cameras may peform better than higher megapixel cameras. Stated another way a billion blurry pixels are less diagnostic than 6 million sharp and properly exposed pixels. 

Step 2: The detector - A CCD camera works because a detector within the camera gives off light (scintillates) when it is activated by x-rays. Different vendors use different scintilators. Some vendors tell you what they use. Some just say "proprietary secret." The two scintillators that are commonly used are Cesium Iodide (CSI) and Gadolinium Oxide (GADOX). 

The type of detector in your camera is important for two reasons. The cost of the machine will be directly related to the scintillator used in the detector and the scintillator has a large effect on system performance. 

It is always difficult to make generalizations about CCD cameras but, as a general rule, based on our experience in our teleradiology service, CSI detectors generate better images at lower dosages than GADOX detectors. In our opinion, the added price of the CSI detector (although sometimes significant) is money well spent. 

Step 3: The camera manufacturer: Knowing who makes the CCD camera within your CCD machine is important. Rarely do vendors make their own cameras. Rather, most  vendors use cameras from another manufacturer. Many vendors use the same cameras in their x-ray machines. It is not uncommon for veterinarians looking at CCD systems to unknowing compare three machines from different vendors which contain exactly the same CCD camera!

Remember, the camera makes the image. The x-ray machine that you see on the outside is a shell for the camera that makes x-rays.  

Knowing who makes the camera is essential because it is impossible to compare systems or ask other veterinarians about their CCD machine without it. In fact, some vendors sell systems made by different camera manufacturers. If you ask another veteriarian how they like their system made by Vendor X and Vendor X sells cameras made by 3 camera manufacturers, how do you know if you are comparing apples to apples?

Step 4: Know what kind of CCD camera (single or array) you are evaluating: Most CCD cameras utilize a single lens and single detector. These types of cameras have been around for a while and are in use in many veterinary practices. At the 2008 SHOWDOWN ,  one vendor will be debuting a new type of CCD detector. This detector uses an array of small cameras and fancy software to stitch together an image from the little detectors. These array CCD cameras are new to the veterinary market. Our experience with them at this time is limited. 

Step 5: Look at images - one extremely important aspect of any digital system is the software processing that is applied to the images. If the software used to create the images stinks it really does not matter what the hardware specs for the camera are. Over and over and over and over again, we see systems that should perform well based on their pixel number and detector type, but the images are a disaster. This is because of poor image processing. The problem is that vendors never talk about image processing during the sales pitch because it is hard to sell image processing. Now you know better. Be absolutely certain that you see images from a live install and NOT just the images the vendor show you. Once vendor who is no longer in business once told me " we could get great images in our lab but could not duplicate them in the field." Ooops. Always look at imaged obtained at a real veterinary installation. A good place to start is the SHOWDOWN DVD.

Another factor to consider with image processing is that your vendor has ALOT of control over what the images look like in your practice. It is common for different vendors selling the same camera to have images that look dramatically different. Vendors have the ability to tweak their images significantly. Some vendors do a good job of this. Some do not. 

Step 6: Know your vendor and distributor-  This is actually the most important factor of all. In our experience, CCD cameras are (for whatever reason) not plug an play. Your vendor/distributor must know how to install the machine and support it or you wil not be satisfied with the results.

Additionally, with some machines, your vendor/distributor are also the ONLY ones who can support the system. If they disappear there is really nobody on earth who can support your machine or give you software upgrades in the future. In other words, if your vendor goes out of business, stops issuing software upgrades, or otherwise stops suporting your CCD machine, you have little more than a giant paperweight if the machine or computer running the machine breaks. 

For a full discusion of this topic click here.  

Step 7: look at everything else - Remember, a digital radiography system is a complete system that includes PACS, service contracts, monitors, software etc. You must evaluate the whole package before deciding on a CCD system. This article might help (click here). 

In summary, when comparing CCD machines, these are the questions you need to ask:

• How many megapixels does the camera have?
  
• What kind of scintillator is in the camera?
  
• What manufacturer makes the CCD inside the X-ray machine?
  
• What vendor is selling the CCD machine (i.e. who puts the CCD camera in the x-ray machine and what x-ray machine do they use)?
  
• Who is distributing the equipment? 
  
• Who is responsible for service on the machine? On the sofware?
  
• Dont forget to evaluate the entire package. Consider PACS, service contracts, software functionality, etc.