American Society of Radiologic Technologist (ASRT) Practice Exam

Increasing the kVp from 60 to 68 will result in which effect?

1. Increased energy of characteristic photons

2. An increase in the number of characteristic photons

3. Increased quantity of bremsstrahlung photons

4. A leftward shift of the emission spectrum

The correct answer is: Increased quantity of bremsstrahlung photons

Increasing the kilovolt peak (kVp) enhances the energy of the x-rays produced during the imaging process. Specifically, when the kVp is raised from 60 to 68, the effect is most significantly observed in the production of bremsstrahlung radiation, which constitutes the majority of x-rays generated. Bremsstrahlung radiation occurs when electrons are decelerated upon interaction with the atomic nuclei of the target material. Higher kVp increases the energy of the electrons striking the target and, consequently, produces a higher quantity of bremsstrahlung photons. This increase in energy leads to a broader spectrum of photon energies and enhances the overall quantity. Thus, with an increase in kVp, there is a notable increase in the number of bremsstrahlung photons produced. The other options focus on characteristic radiation, which is produced when electrons from the outer shell fill vacancies created by the removal of inner-shell electrons. This is not directly related to the change in kVp as significantly as bremsstrahlung radiation, and therefore, they do not reflect the predominant effect of increasing kVp in this situation.