Out-of-Field Artifact - Video Lesson

Scanning a morbidly obese patient presents a lot of potential problems. One of these potential problems is what we call the out of field artifacts. It's really not uncommon for bariatric patients to be just small enough that they fit inside of the CT scanner but not actually fit inside of the scan field of view. You see, the scan field of view is not the same size as the gantry. Scan field of view is actually slightly smaller than the gantry opening. And if the patient is larger than the scan field of view, what we get is this out of field artifact. The out of field artifact is called out of field because it's caused by parts of the patients being outside of the scan field of view. It's okay if the patient has parts outside of the display field of view. But if it's outside of the scan field of view, that's when it becomes an issue. These parts of the patient that are outside of the scan field of view are still going to attenuate x rays. And so the scanner just has to assume that the