American Registry of Radiologic Technologists (ARRT) Practice Exam

The phenomenon that results from the dispersion of x-ray photons as they move away from the source is divergence. Divergence refers to the spreading out of x-ray beams as they travel through space. This is a fundamental characteristic of x-ray emission; when x-rays are generated, they do not travel in a perfectly straight line but instead fan out away from the focal point of the x-ray tube.

This scattering of x-ray photons leads to a broadening of the beam, which is important to understand in radiographic imaging because it affects dose distribution and image quality. The degree of divergence can influence the exposure levels at various distances from the source as well as the sharpness of the structures being imaged.

Other options like converging beam refer to a different behavior of radiation where the rays are brought together, typically seen with lenses. Refraction involves the bending of waves when they pass from one medium to another, which is not applicable in this context as x-ray photons interact with materials differently. Diffraction is related to the bending and spreading of waves around obstacles or openings, which occurs with different physical principles influenced by wavelength but is not the primary action affecting x-ray photons in this scenario. Hence, the correct understanding of divergence directly relates to the dispersion of x