image production 110820 Flashcards

1
Q

Quality assurance and maintenance of CR cassettes include cleaning and inspecting the plates at least

A

every 3 months

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2
Q

Quality assurance and maintenance of CR include erasing the plates at least

A

every 48 hrs

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3
Q

Quality assurance of digital imaging reqs the uniformity of processing codes to ensure

A

image appearance consistency

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4
Q

softwiare function that evens the brightness displayed in the image is called

A

smoothing

smoothing software may result in loss of detail

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5
Q

Beam part receptor alignment latitude describes

A

the latitude of collimation that still allows the software to detect collimated edges.
Detection of collimated edges is crucial for accurate histogram

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6
Q

In DR inappropriate collimation causes

A

hisechtogram analysis error

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7
Q

An artificial increase in display contrast act an edge of the image is

A

edge enhancement

this enhances visibiltiy of detail

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8
Q

If the exposure field is not accurately recognized the histogram will contain data

A

outside the exposure field, widening the histogram

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9
Q

Digital image receptors are more sensitive to

A

scatter radiation and background radiaition

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10
Q

Digital imaging is driven by

A

exposure

“Total Exposure” reaching IR

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11
Q

Digital systems operate at what speed class

A

the speed class chosen by the radiographer

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12
Q

As speed class increases

A

The likelihood of noise increases

Increase in KVP and decrease in mAs causes increase in quantum mottle/ or noise

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13
Q

As speed class decreases

A

Pt exposure increases

More “Total Exposure” reqd to produce useable image

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14
Q

Excessive processing of the digital image may

A

degrade visibility of anatomy

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15
Q

A high SNR provides an image with

A

higher spatial reso

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16
Q

Quantum noise limits ability to see

A

detail

17
Q

Grid ratio

A

“The ratio of the HEIGHT of lead strips over the he DISTANCE between the lead strips.
*expressed as H/D

18
Q

Grid frequency

A

amount of lead in grid

*expressed number of lead strips per inch

19
Q

main function of grids

A

prevent compton scatter fr reaching IR

20
Q

contrast improvement factor

A

measure of the grid to enhance contrast

21
Q

grid selectivity

A

ratio of primary radiation transmitted thru grid to secondary radiation transmitted thru the grid

22
Q

lead strips and aluminum interspacers angled to coincide with the divergence of the XR beam is called

A

focused grid

23
Q

range of SIDs used with focused grids

A

grid radius

24
Q

best scatter clean up is achieved by

A

crosshatch grids

25
Q

grid cutoff

A

decreased density on a radiograph as a result of absorption of image-forming rays

26
Q

use of airgap

A

works bc scatter travels in divergent paths and misses IR as a result of increased OID

27
Q

when using AEC increasing KVP

A

has no effect on image quality

BC after a certain amount of radiation hits the ionization chambers the exposure terminates