Exam 3 Flashcards
Due to patient circumstances you have to increase SID and want to keep a consistent OD. Which law/rule will help to keep a consistent OD with the change in SID.
Direct square law
Due to patient circumstances you want to decrease patient exposure and keep a consistent OD. Which rule/law will help?
15% rule
All images on a radiograph demonstrate some level of an increase is size of objects compared to the anatomy they represent. This is called what?
Magnification
How does having a smaller focal spot affect spatial resolution?
Small focal spot increases sharpness/spatial resolution of an image
How does increasing SID affect spatial resolution?
It increases detail and spatial resolution
How does positioning the part of interest parallel with the image receptor affect spatial resolution?
Increases spatial resolution and decreases shape distortion
There are positive and negative contrasts. Barium is a __________ and air is a __________ contrast.
Positive; negative
What type of contrast is determined by the size, shape, and x-ray attenuating characteristics of the subject who is being examined and the energy of the x-ray beam
Subject contrast
Which resolution (in regards to image quality) is the ability to image small objects that have high subject contrast?
Spatial resolution
What resolution (regarding image quality) is the ability to distinguish anatomical structures of similar subject contrast (Ability to distinguish between similar tissues)
Contrast resolution
T/F: In radiography, density is a visible representation of the quantity of X-ray photons reaching the IR.
True
T/F: Increasing mAs increases density.
True
Blurred region would seen over entire image; technologist has a lot of control over reducing this type of blur
Motion blur
Blurred region on the outer most edge of the image; technologist has little or no control over
Focal spot blur
Decreasing kVp [x] beam attenuation [y] absorption and [z] transmission.
Increases; increases; decreases
Increasing kVp [x] beam attenuation [y] absorption and [z] transmission
Decreases; decreases; increases
Decreasing tissue atomic number [x] beam attenuation [y] absorption and [z] transmission.
Decreases; decreases; increases
Increasing tissue atomic number [x] beam attenuation [y] absorption and [z] transmission
increases; increases; decreases
Decreasing tissue thickness [x] beam attenuation [y] absorption and [z] transmission
decreases; decreases; increases
Increasing tissue density [x] beam attenuation [y] absorption and [z] transmission
increases; increases; decreases
Muscle tissue has atomic particles that are [x] dense or compact than fat cells and therefore attenuate the x-ray beam [z] than fat cells
more; more
The range of exposures (aka the number of shades of gray) that can be accurately detected on an analog image
Dynamic range
Using a positive contrast produces more brightness in a specific area (for example, barium in the stomach) than the adjust tissues. Therefore, positive contrast [increases/decreases] attenuation
increases
The chest represents high contrast anatomy (high subject contrast). Therefore, which of the following is most appropriate?
high kVp
high mAs
low kVp
low mAs
High kVp
The _______ atomic number of a material, the _____ the number of photoelectric absorption interactions will be.
higher; higher
The device for removing long-wavelength radiation from the primary x-ray beam is the:
filter
Low quality x-rays will _________ attenuation in biological tissue of the same thickness and
Increase
If the radiograph (specifically an analog image) is under penetrated, the technologist can compensate by
Increasing kVp
requires an increase in technical factors because the affected body tissue increases in thickness, resulting in more attenuation of the X-ray beam
Additive disease
All affect differential absorption except
-X-ray quantity
-Tissue mass density / tissue atomic number
-kVp
X-ray quantity
A non-diagnostic image shows a long scale of radiographic/image contrast due to excessive penetration. Which technique change would be appropriate?
lower kVp
A destructive disease, takes away from tissue density. For example, osteoporosis results from the loss of calcium of the bone. Therefore, would cause the bone to appear more:
radiolucent
The thicker the body part, the greater the ________ of radiation needed to produce an acceptable image.
quality and quantity
The primary function of mAs for an analog image (film/screen image) is to:
Regulate density
The optical density of a radiograph can be increased by employing a:
Higher mAs value
The difference in radiographic density between any two adjacent portions of the image is called:
contrast
Short scale radiographic/image contrast in a radiograph is increased by
Decreased kVp
Penetration of a part to be radiographed is primarily a function of the:
kVp
Motion of the patient either voluntary or involuntary, during the exposure will result in decreased:
Detail
If you halved the time of exposure, how much would you change the mA to obtain the same density on the radiograph?
double the mA
If kVp is decreased, what happens to recorded detail?
It has no effect
If 60 mAs was set with 0.3 seconds, what was the mA?
200 mA
If 10 mAs was set with a 300 mA, what was the seconds?
0.03
Generally speaking, what do destructive pathologic conditions require?
Decreased kVp
A radiograph is taken at 100 mA and 2 seconds. The finished radiograph exhibited patient motion. The new time if the mA is increased to 400 would be:
1/2 second
In an analog image, a longer scale of radiographic / image contrast within the part can be obtained by
increasing the kVp
