How do photons change with an increase in kilovoltage peak (kVp)?

When kilovoltage peak (kVp) is increased, the energy of the emitted photons also increases. Since the energy of photons is directly related to their frequency, an increase in energy results in an increase in frequency. This relationship is based on the fundamental equation of electromagnetic radiation, E = hf, where E is energy, h is Planck's constant, and f is frequency.

As the frequency of the photons increases, their wavelength simultaneously decreases, as indicated by the equation that relates wavelength (λ) to frequency (f): c = λf, where c is the speed of light. Therefore, a higher frequency corresponds to a shorter wavelength.

Thus, with an increase in kilovoltage peak, the resulting photons possess both increased frequency and decreased wavelength, leading to more penetrating x-rays capable of producing higher quality images. This understanding is pivotal in radiography, as it influences the contrast and detail of the images produced.