Exam 1 S2 Flashcards
1
Q
What is photoelectric effect?
A
when an x-ray photon strikes an inner shell electron
2
Q
What happens in order in the photoelectric effect?
A
- electron absorbs ALL x-ray photons energy
- x-ray photon ceases to exist
- excess binding energy is given to the inner shell electron
- inner shell electrons speed up and exit atom
3
Q
What happens to the electron in photoelectric effect?
A
electron absorbs all the x-ray photon’s energy (transmitted)
4
Q
What happens to the x-ray photon after the interaction with the electron?
A
x-ray photon ceases to exist
5
Q
Where does the inner shell electron go?
A
after this interaction it speeds up and leaves the atom
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Clover:
In Compton scatter, the ____ _____ interacts with an ________ shell electron
x-ray photon
outer (loosely bound)
100
Clover:
What happens to the outer shell election in compton scatter?
it gets knocked out and becomes a free electron
101
Clover:
What is the name of the electron once Compton scatter takes place?
Compton electron
102
Clover:
The remaining energy in the atom after ejecting the electron, turns into?
a Compton photon
(goes in all directions)
102
Clover:
what is image contrast?
visible difference in brightness levels within x-ray
102
Clover:
Compton scatter increases occupation does because of _____
scatter
(throughout the area)
103
Clover:
Compton scatter increases _____ _____ because of _______
patient dose
ionization
104
Clover:
How do air in the abdomen affect subject contrast?
increases subject contrast
(air shows up black)
104
Clover:
Compton scatter decreases image ______
contrast
104
Clover:
What does Kvp do to the image contrast?
Why is this?
high kVp decreases contrast
due to scatter
(more kVp= more scatter= less contrast)
105
Clover:
what would have low subject contrast?
abdomen
(all greys, same radiation)
105
Clover:
what is subject contrast?
how different tissues absorb radiation
(ex chest: lung vs clavicle)
106
Clover:
What x-ray would have high subject contrast?
chest x-ray
(some black, white, & greys)
107
Clover:
What outside factors could create additional subject contrast?
iodine
barium
air
107
Clover:
What does pneumothorax do to subject contrast?
increases subject contrast
(air shows up black)
108
Clover:
How does ascites affect subject contrast?
decreased contrast
(adds more greys to the x-ray)
108
Clover:
What does pneumonia do to subject contrast?
decreases subject contrast
(more greys)
109
Clover:
what does an air-filled bowel obstruction do to subject contrast?
increases subject contrast
(more black)
109
Clover:
For a obese patient what happens to subject contrast?
it decreases
(begins to show up as the same)
109
Clover:
What does COPD do to subject contrast?
why?
increases subject contrast
(more air = more black in x-ray)
109
Clover:
What can magnification in image quality lead to in diagnostic x-ray?
improper diagnoses
(heart magnified)
110
Clover:
if you increase SID you ______ magnification
decrease
110
Clover:
What factors affect image magnification?
SID (source to image distance)
OID (object to image distance))
SOD (source to image distance)
110
Clover:
What does spatial resolution refer to?
sharpness in the x-ray
110
Clover:
If you decrease SID you _______ magnification
increase
110
Clover:
110
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111
Clover:
If OID decrease, magnification ______
decreases
111
Clover:
If OID increases, magnification ______
increases
111
Clover:
If SOD increases, magnification _____
decreases
111
Clover:
What is the most important outcome when calculating the magnification factor (MF)?
finding the actual size of the anatomy
111
Clover:
How do we calculate the magnification factor?
image size / object size
or
SID/SOD
112
Clover:
How do we find the object size?
image size / magnification factor
112
Clover:
spatial resolution is not the same as:
contrast
brightness
distortion
receptor exposure
113
Clover:
What is a big factor that affects spatial resolution?
patient motion
113
Clover:
high spatial resolution, can be referred to as: (3)
high detail
high sharpness
low blur
113
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114
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114
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115
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