chapter 10 (x ray interaction with matter) Flashcards
As Z _____, the probability of Compton scatter ____.
increases, remains the same
At energies less than ____ is the only time coherent scatter interactions are somewhat probable in soft tissue.
15 Kev
Compton scatter is directed at (a) ______ angle from the incident beam.
Any
When the mass density of the absorber is ____, it results in ____ Compton scatter.
increased, increased
K-shell binding energy increases with increasing
atomic number
The scattered X-Ray from a Compton interaction usually retains _______ of the energy of the incident X-Ray.
most
As kVp _____, the probability of Compton scatter ____
increases, decreases
An incident X-Ray interacts with an atom without ionization during ______.
coherent scattering
As kVp _____, the probability of coherent scatter ____
increases, decreases
At energies greater than ____ Compton scatter interactions become most probable in soft tissue.
25 keV
Materials with higher atomic numbers have lower _____.
transmission
__________ requires at least a 1.022 MeV X-Ray to occur.
Pair production
What is CT used for in PET/CT in nuclear medicine?
It shows better resolution images for anatomy and makes the PET image better
Which of the following is not one of the five basic X-Rays interactions with matter?
Bremsstrahlung
At ~20 keV, the main X-Ray interaction in soft tissue and bone is ______
photoelectric absorption
The two primary forms of X-Ray interaction in the diagnostic range are ______.
Compton scattering and photoelectric absorption
Which X-Ray interaction generally involves ejection of an outer shell electron?
Compton scattering
There is complete absorption of the incident diagnostic X-Ray photon causing ionization with ________.
photoelectric effect
Image fog in diagnostic imaging is caused by
Compton scatter
After photoelectric absorption, there will be ______.
a scattered electron
A negative contrast agent is ____.
air
The addition of scattered X-Rays to the image receptor______
degrades contrast
The use of contrast agents increases the amount of __________.
Compton scatter
photoelectric absorption
differential absorption
(All of the above)
X-Rays transmitted without interaction contribute to _______.
the radiographic image
Radiographic contrast is ________.
the difference in attenuation between adjacent areas
The beam exiting the patient is mostly ______.
high energy X-Rays
Radiographic contrast depends on ________.
kVp
tissue thickness
tissue density
(all of the above)
Higher energy X-Ray beams have lower ______ than X-Ray beams with lower energy.
attenuation
Barium and iodine are good contrast agents because of their _________.
high atomic number
Only at the highest X-Ray energies, around 10 MeV, can ____ take place.
photodisintegration
About ____ of the incident beam from the X-Ray tube contributes to the finished image.
0.5%
Differential absorption is dependent on the ________.
kVp of the exposure.
atomic number of the absorber.
mass density of the absorber.
(All of the above.)
