Radiology Tech Physics Practice Test

When thinking about what lowers an X‑ray beam’s intensity, focus on how photons are removed from the primary beam either by interactions or by traveling geometry. Filtration and Compton scattering both reduce the amount of photons that reach the target or detector: filtration absorbs photons, especially the softer ones, decreasing flux; Compton scattering knocks photons out of the primary beam path, lowering the beam intensity along its original direction. Increasing distance also diminishes intensity due to the inverse-square law—the beam spreads out as you move away from the source.

The characteristic effect, however, is about how the X-ray spectrum is produced in the target material. When an inner-shell vacancy is created, electrons from higher shells fill it and emit photons at energies specific to the target (characteristic radiation). This process adds photons at certain energies and is part of producing the beam rather than attenuating the photons that travel toward the patient or detector. So it does not inherently reduce the primary beam’s intensity, making it the best choice for the item that will not reduce intensity.