Attenuation - Video Lesson

Welcome back. This lesson is about attenuation. Attenuation is a word we use in radiology that has a very specific definition. Attenuation is defined as a decrease in x-ray beam intensity due to interactions and matter. It's a pretty straightforward idea during a CT exposure, a portion of the X-ray beam is attenuated by the patient, and the remainder is transmitted through the patient. These interact and matter refer to coherent scattering, the photoelectric effect, and compton scattering. All of those things result in attenuation. So here's an example of what that looks During a CT procedure, we aim an X-ray beam at the patient. Some of those X-ray photons pass all the way through, so that's transmission But some of those x-ray photons are stopped inside of the patient, and that's the idea of attenuation. Part of the x-ray beam is transmitted end part of the x-ray beam is attenuated. Attenuation is important because the attenuated photons are the ones that are responsible for ionization