Bioimaging Important Concepts for Final

ionization

ejection of electrons from an atom, creating free electrons and an ion

forces that induce ionization of an atom

EM radiation and particulate radiation

which EM bands can induce ionization?

only high photon energy x-ray and gamma rays are ionizing radiation; low photon energy optical light is NOT ionizing radiation

bremsstrahlung x-ray

primary source of x-ray photons in an x-ray tube

photoelectric effect

primary mechanism that provides contrast of x-ray imaging between different types of tissue

compton scattering

primary mechanism for limiting the resolution of x-ray imaging

photoelectric effect leads to…

attenuation of the incident x-ray intensity, which forms the x-ray imaging contrast

compton scattering leads to…

re-direction and reduction of energy of the incident x-ray photons, representing the “noise” in x-ray imaging

intensity is…

power passing through a unit area; equal to the energy per area and per time