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Chapter 8 Bushong

Terms in this set (25)

Grays in air are the measurement for x-ray _________.
x-ray quantity exposure and intensity all of the above
The number of x-rays in the useful beam defines x-ray
quantity
X-ray quantity increases in direct proportion to increases in __________.
mAs
If the distance from the source to the image (SID) is reduced by half, how is the x-ray intensity at the image affected?
It is increased 4 times
If filter thickness is ________, then x-ray intensity is ________.
both B and C: increased, reduced
reduced, increased
Which of the following occur during x-ray tube preparation or "boost?"
1. The collimator light goes out to save energy.
The anode comes up to rotational speed.
The preselected milliamperage increases in the cathode filament.
A high voltage is applied across both diodes of the x-ray tube, enabling electrons to travel across to the anode.
The grid in the table begins to oscillate.
2 and 3 only
A 10% increase in kVp has ________ effect on x-ray intensity than/as a 10% increase in mAs.
much greater
If the quantity of electrons hitting the target are doubled, the x-ray quantity is __________.
increased by a factor of 2
If a technologist changes the technique from 70 kVp @ 200 mAs to 70 kVp @ 400 mAs, the x-ray intensity will _________ and optical density will __________.
double, double
What is the approximate amount of current necessary for thermionic emission to occur at the filament
3-5 amps
The inverse square law has the same effect on optical density and x-ray _________.
All of the above: x-ray intensity, x-ray exposure, x-ray quantity, and optical density.
An increase of 15% in kVp is equivalent to increasing mAs _____.
100%
If the intensity of a 70 kVp exposure at 20 mAs is 1.0 mGya, what would it be at 5 mAs?
.25 mGya
If an exposure is 0.5 mGya at an SID of 40 inches, what would the exposure be at an SID of 60 inches?
0.22.2 mGya
The penetrability of an x-ray beam is called x-ray ________.
quality
An x-ray beam that could pass through dense tissue would have high _____.
Both A and B: high quality and penetrability.
A low quality beam would also have low _____.
penetrability
Beam quality is affected by ______________.
kVp and filtration
The half value layer (HVL) of an x-ray beam is a measurement of beam _______.
quality
Image contrast is affected by ________.
Both A and B: beam quality and kVp
The HVL is lowered by a decrease in ________.
kVp
X-ray beam quality is improved by ____________.
increasing filtration
The main purpose of added filtration is to reduce
patient dose
Added filtration will ______ beam quality and ______ beam quantity.
increase, decrease
A compensating filter is used to create ________ optical density with a body part of _________ thickness.
uniform, non uniform
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