Radiation Interactions - Video Lesson

Welcome back. In this lesson, I'll be taking you back to your days in X-ray school. We'll be talking about radiation interactions. When an x-ray photon enters the human body, there's basically four things that can happen. Transmission, coherent scattering, photoelectric absorption, or compton scattering. During a CT exposure, literally billions of x-ray photons are going to pass through the patient and they all interact in one of these four ways. From a biological standpoint, some of these interactions are harmful to the patient while others are not. And let's start by talking about the non ionizing interactions. During a CT exposure, many, many trays are going to pass through the body without interacting in any way at all. We call this transmission, but really that just means nothing is happening. The X rays aren't absorbed. They're not scattered. They just pass through the patient, and then they get measured by the detector array. So from a biological standpoint, transmission is a good thing because