What major interaction occurs between x-rays and adipose (fat) tissue?

The interaction that primarily occurs between x-rays and adipose (fat) tissue is Compton scattering. This process is significant because fat tissue has relatively low atomic number elements, which makes it less effective in absorbing x-rays through the photoelectric effect.

In Compton scattering, an incident x-ray photon collides with a loosely bound outer electron in adipose tissue, transferring some of its energy to the electron and causing it to be ejected from its atom. The x-ray photon, now with reduced energy, continues on in a different direction. This interaction is particularly relevant in medical imaging because it contributes to the overall attenuation of the x-ray beam, influencing the appearance of images produced during diagnostic procedures.

Other interactions mentioned, such as coherent scattering and the photoelectric effect, have lesser relevance in adipose tissue. Coherent scattering involves lower energy photons and does not significantly contribute to image production due to its non-energy degrading nature. On the other hand, the photoelectric effect is more predominant in higher atomic number tissues where absorption can occur more efficiently. Transmission refers to the passage of x-rays through a material without interaction, which is also not the major interaction occurring in this context.