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RADT465 Image Eval.
ARRT registry review covering image acquisition and evaluation content area.
Question | Answer |
---|---|
The chief advantages of SF imaging | high spatial resolution and uniformity in image appearance |
Any combination of mA and time that will produce a given mAs will produce identical receptor exposure | reciprocity law |
The intensity of light at a particular distance from its source is inversely proportional to the square of the distance | inverse square law |
As distance is decreased, the intensity of the x-ray beam | increases |
As kV is ____________, more electrons are driven to the anode with greater speed and energy | increased |
Responsible for most of the scattered radiation that reaches the IR | Compton scatter |
The single most important way to reduce the production of scattered radiation | collimation |
A device that functions to absorb a large percentage of scattered radiation before it reaches the IR | grid |
The addition of a grid must be accompanied by an ______ in mAs | increase |
Angulation against the lead strips causes | grid cutoff |
Lateral decentering against a grid causes | uniform loss of exposure |
General radiographic fixed equipment usually uses which grid | 10:1 or 12:1 |
Total primary bream filtration | 2.5-mm Al |
Filtration increases | the overall average energy of the beam |
Example of destructive conditions | osteoporosis, necrosis, emphysema |
Example of additive conditions | ascites, Paget's, atelectasis |
kV affects the ___________ of the x-ray beam | quality and quantity |
To double or halve the receptor exposure, the kV can be increased or decreased by __% | 15% |
Used to provide more uniform radiographic density when imaging structures having widely different attenuation coefficients | compensating filters |
Two-dimensional picture element | pixel |
the number of bits per pixel and identifies the values of gray | bit depth |
a graphic representation of pixel value distribution demonstrating the number of pixels and their value | histogram |
controls the shades of gray | window width |
controls brightness | window level |
The ______ the contrast resolution, the better the ability to see similar adjacent gray shades | higher |
When there are just a few densities, with noticeable difference between them, radiographic contrast is ___ or ______ scale | high; short |
When there are many shades of densities with only slight difference between them, contrast is ___ or _____ scale | low; long |
What is particularly critical when using AEC | positioning and centering |
___________ improves with smaller pixel size, smaller pixel pitch, and larger image matrix | spatial resolution |
Anything that interferes with visualization of the image we wish to see | noise |