X-Ray Interactions
Compton scattering
Ei = Es + Eb + Eke
Barium is a good contrast agent because of its ____.
High atomic number
Which atomic shell possesses the highest binding energy?
K
K-shell binding energy = 0.53 keV
oxygen
High kVp techniques reduce _____.
patient dose
At energies below 40 keV, the predominant x-ray interaction in soft tissue and bone is _____.
photoelectric absorption
When an x-ray photon with a slightly greater energy than the binding energy of the inner-shell electron interacts with that inner-shell electron, the following interaction results:
photoelectric absorption
Which x-ray interaction involves the ejection of the K-shell electron?
photoelectric absorption
In ____, there is complete absorption of the incident x-ray photon.
photoelectric interaction
product of pair production
positron
The electron dislodged during Compton scattering is called the
recoil electron.
When x-ray photons interact with matter and change direction, the process is called
scatter
X-rays transmitted without interaction contribute to _____.
the radiographic image
photoelectric effect
total absorption
The scattered x-ray from a Compton interaction usually retains _____ of the energy of the incident photon.
most
_____ occurs only at the very high energies used in radiation therapy and in nuclear medicine P.E.T. imaging.
Pair production
Differential absorption is dependent on (the) _____.
kVp of the exposure atomic number of the absorber mass density of the absorber
Compton scatter is directed at _____ angle from the incident beam.
any
K-shell binding energy increases with increasing ____.
atomic number
yield photons with each transition
characteristic cascade
An incident x-ray interacts with an atom without ionization during _____.
coherent scattering
no loss in energy
coherent scattering
An outer-shell electron is ejected and the atom is ionized during _____.
compton interactions
The two primary forms of x-ray interaction in the diagnostic range are _____.
compton scattering and photoelectric absorption
As the angle of deflection is increased from 0° to 180°,
greater energy is imparted to the recoil electron.
As kVp ____, the probabilities of photoelectric absorption ____.
increases, decreases
When the mass density of the absorber is _____, it results in _____ Compton scatter.
increases, increases
