Does coherent scatter result in patient dose?

Coherent scatter, also known as Rayleigh scattering, involves the interaction of low-energy photons with matter, causing the photons to change direction without a loss of energy. In this process, the incident photons interact with the entire atom, leading to excitation of the atom's electron shells rather than ionization or significant energy transfer. This transition does not impart measurable energy to the tissue, which means it does not contribute to patient dose in a meaningful way.

The reason this is significant is that while coherent scatter does occur, it does not result in ionizing radiation or significant damage to biological tissues, as higher energy interactions would. Therefore, while other interactions (like photoelectric absorption or Compton scattering) can increase patient dose due to the loss of energy and the potential for biological effects, coherent scatter remains a non-contributing factor in terms of radiation dose. This understanding is essential for evaluating the overall patient exposure in fluoroscopy and imaging practices.