American Society of Radiologic Technologist (ASRT) Practice Exam

What is another term for classical scattering?

1. Compton

2. Coherent

3. Characteristic

4. Photoelectric

The correct answer is: Coherent

Classical scattering, also known as coherent scattering, is characterized by the interaction of photons with matter without any energy loss. In this process, the incoming photon interacts with the entire atom, resulting in scattering without a change in the photon's energy, although there may be a change in its direction. This phenomenon primarily occurs with low-energy photons, where the wavelength of the incident radiation is comparable to the dimensions of the atom. Coherent scattering is foundational for understanding the principles of radiographic imaging and the behavior of x-rays as they pass through different tissues. This term is often emphasized in radiology as it elucidates how certain imaging techniques exploit these scattering phenomena to enhance image quality or reduce unwanted noise. The other terms listed refer to different scattering or interaction processes. For example, Compton scattering involves a photon transferring some of its energy to a loosely bound outer electron, resulting in a change in both the photon's direction and energy. Characteristic interactions are associated with the ejection of inner-shell electrons and the subsequent transition of outer-shell electrons, which also does not represent classical scattering. The photoelectric effect describes the complete absorption of a photon by an atom, leading to ionization, which further distinguishes it from coherent scattering. Understanding these variations helps clarify the interaction