One of the common problems C-arm owners contact us about is artifacts- and we don't mean the cool, Indiana Jones, hidden-in-a-lost-temple kind. Artifacts in your C-arm image- spots, streaks, smudges or any other foreign form showing up in your field of view- can be the result of several underlying issues. Some of these are physical issues with the hardware. Others are digital issues in your C-arm's computer. Whichever the case may be, we want to help you troubleshoot your C-arm image artifacts and learn the next step to take in eliminating them.
Causes of C-Arm Image Artifacts
Debris (Physical Artifacts)
Many artifacts appear as a result of dirt or dust getting inside the system from the surrounding environment. They can also be debris from inside the C-arm's own image intensifier (II). Over time, the phosphor lining inside an II can break down and flake off. While "phosphor flakes" might sound like the name of a delicious, sugar-coated breakfast cereal, the artifacts they cause indicate the need for a pretty serious parts replacement.
Compromised Processing Chain (Digital Artifacts)
A broken or bad connection, or outright failure, among the parts in the image processing chain can cause digital artifacts (pixellation) to appear.
Troubleshooting C-Arm Image Artifacts
The first step in troubleshooting your image artifact is to determine the nature of the cause. Look closely at the artifact and note the finer details of its appearance. Physical artifacts caused by debris are typically specks or spots with rounded, blurred edges. They can also come in the form of streaks. Digital artifacts tend to be squarish- or pixellated- in appearance with clear edges.
If the appearance of your artifact leads you to believe the cause is physical, your second step is to locate the debris. Dust and lint can live in a lot of places inside your C-arm, but if it's showing up in your images, it's definitely in one of four places: the camera, the II, the collimator, or the tube port.
One trick you can easily use to determine location is a quick magnification test. Start by taking an image in normal mode. Note the size and position of the artifact, then take another image in magnification mode 1 or mode 2 and see if it changes size or position. If the artifact stays the same size, this tells you that it's either in the top of the II (the II lens) or in the camera. If the artifact changes size and/or position, it's either in the lower part of the II or the tube port.
If the artifact does not change during the magnification test then the first thing to try is cleaning the camera lens. An air puffer, like those used to clean a regular photo camera lens (around $10 at any place that sells handheld cameras), will take care of dust in most cases. If the lens has a smudge on it, wipe it away with an eyeglass cloth.
If cleaning the lens doesn't change anything, it may be that the artifact is inside the camera. In this case, unfortunately, there isn't much to be done other than replacing the camera.
If the artifact magnifies, you should clean the grid on the II and the pan behind it, as well as the collimator and the tube port. When cleaning behind the grid, only use the air puffer on the silver part. In most systems, this area is helpfully labeled "don't touch" to jog your memory. Unfortunately, just like debris inside a camera, if an artifact is inside the II and can't be cleaned away, the II will have to be replaced to fix this issue.
A digital artifact is usually an issue with one of the image processing boards. Sometimes an artifact can be caused by a poor connection at a board or a cable. To eliminate this possibility, a good first step is to re-seat the cables and boards to ensure strong connections. If this doesn't take care of the problem, you may have to place a service call and replace some of the boards.
Whether or not you're experiencing C-arm image artifacts right now, there is potential for any C-arm to develop them at one point or another. When artifacts show up, taking a little bit of time to follow the steps above can preclude the greater cost and downtime of placing a service call.
If the methods above don't solve your artifacts and you need more help, our Parts and Service Teams are ready to assist. Call us, or use the link below to tell us about your problem.