Filtration - Video Lesson

Hey, everybody. Welcome back. This lesson is about filtration used in radiography. It's really important to understand filtration because this is a process that removes the low energy photons from the x-ray beam and decreases patient dose. Filtration has other side effects, but decreasing patient dose is the main purpose for its use. Why is filtration necessary? An unfiltered x-ray beam has a huge number of low energy photons represented by the yellow photons in this illustration These photons don't have enough energy to penetrate the patient. Instead, they get absorbed in the patient's skin without adding anything to the image. We call this the entrance skin dose or ESD. Filtration helps to correct this problem. Adding filtration decreases the entrance skin dose.