Ch. 3 Flashcards
Fog is created by
scatter
___ effect is not dependent on atomic # of tissue
compton
___ effect is dependent on energy of incoming photon
compton
___ effect: complete absorption of the incoming photon
Photoelectric
The ___ effect occurs when an incoming photon loses some but not all of its energy, then changes its direction.
Compton
In __ the Compton effect is used.
RT
In __ the photoelectric effect is used.
Diagnostic Radiography
____ occurs when the primary x-ray beam loses some of its energy (number of photons) as it interacts with anatomic tissue.
attenuation
3 possible things that happen during attenuation:
- absorption
- scatter
- photon transmission (hits the image receptor)
Probability of photoelectric effect is dependent on the ___ photon and ___.
energy of the incoming x-ray, tissue atomic #
Fewer interactions occur at higher kVp, but of those that do occur, the # of ___ is more likely.
compton
The following describe the ___ effect:
- X-ray ionizes atom
- Low energy secondary x-ray photon created
Photoelectric
can occur within all x-ray energies and is dependent only on the energy of the incoming photon, not the atomic number of the tissue.
compton effect
X-rays are attenuated exponentially and generally reduced by ~ 50% for each 4 to 5 cm (1.6” to 2”) of tissue thickness. - This is why ___ is changed in obese pts
kVp
Tissues composed of a higher atomic number will ___ beam attenuation
increase
Increasing the compactness of the atomic particles (or density) will ___ beam attenuation
increase
Higher kVp increases the energy of the x-ray beam and will ___ beam attenuation.
decrease
4 factors affecting beam attenuation:
- tissue thickness
- type of tissue
- tissue density
- x-ray beam quality
Remnant or exit radiation is composed of ___ and ___ radiation.
transmitted, scattered
Scatter radiation reaching the image receptor creates ___
Fog
Air (low density) and fat (low atomic number) appear as ___ areas on the image
dark
___ structures and structures with ___ atomic # appear light on the image
dense, high
accuracy of structural lines (sharpness) is ___ and ___.
resolution/recorded detail, distortion
Visibility of anatomic structures is ___ and ___.
density, contrast
