At what percentage of the beam does bremss radiation typically occur below 70 kVp?

Bremstrahlung radiation, or "braking radiation," occurs when high-energy electrons are decelerated or deflected as they interact with the atomic nuclei of the target material, typically tungsten, in an x-ray tube. At lower kVp settings, such as below 70 kVp, the majority of the produced x-ray photons are due to bremsstrahlung interactions rather than characteristic radiation which occurs at higher energy levels.

When operating below 70 kVp, bremsstrahlung radiation constitutes approximately 100% of the x-ray beam output. In this range, the electron interactions predominantly result in the production of these lower-energy x-ray photons rather than the higher-energy characteristic x-rays that are associated with specific energy transitions of the target material's electrons. As the kVp increases beyond 70, the contribution of characteristic radiation starts to rise, but below this threshold, bremsstrahlung is overwhelmingly the primary type of radiation produced.

Therefore, stating that bremsstrahlung occurs at 100% under these conditions reflects the predominance of this type of radiation in the x-ray emission spectrum at lower kVp settings. This understanding is key for radiologic technologists and helps inform them about the nature of the radiation they are working with, especially