What do we call the absorption of x-rays by matter?

The term used to describe the absorption of x-rays by matter is "attenuation." Attenuation refers to the reduction in the intensity of the x-ray beam as it passes through a material, which occurs due to the absorption and scattering of the x-rays by the atoms in the material. This process is crucial in radiography, as it determines the contrast and details seen in the resulting images.

In radiographic practice, understanding attenuation is important for optimizing image quality and ensuring proper exposure levels, as different tissues in the body absorb x-rays to varying extents. For example, denser tissues absorb more x-rays than less dense tissues, which is why bones appear lighter on radiographs compared to soft tissues.

The other terms are related to different concepts: dissipation typically refers to the loss of energy in a system, scattering pertains to the deviation of x-ray paths when they interact with matter without being absorbed, and reflection involves bouncing back of an x-ray beam from a surface without being absorbed. Understanding these distinctions helps in mastering the principles of how x-rays interact with various materials in radiographic imaging.