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w.RADT 171: Fundamentals II > digital systems > Flashcards

digital systems Flashcards

1
Q

film-type radiograph

A

analog

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2
Q

smallest component of the matrix; a greater number of smaller ______ improves spatial resolution; “picture elements”

A

pixels

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3
Q

image displayed as a combination of rows and columns (array)

A

matrix

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4
Q

number of bits that determines the precision with which the exit radiation is recorded and controls the exact pixel brightness that can be displayed

A

pixel bit depth

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5
Q

pixel size is _____ related to the FOV and _____ to the matrix size

A

directly, inversely

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6
Q

the greater the pixel bit depth, the _________ the digitization of analog signal and the _________ the number of shades of gray available for image display

A

more precise; greater

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7
Q

increasing pixel bit depth _______ contrast resolution

A

increases

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8
Q

CR has ___; DR has ____

A

2 steps, 1 step

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9
Q

the IP in computed radiography layers in a cross section

A

protective layer
phosphor layer (turbid)
reflective layer
conductive layer
support layer

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10
Q

types of phosphor layers

A

turbid (random), structured (columnar)

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11
Q

three stages of CR processing

A

scanning, sampling quantization

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12
Q

what type of laser is the CR reader?

A

neon helium laser

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13
Q

how often the analog signal is reproduced in its digitized form

A

sampling frequency

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14
Q

distance between sampling points

A

sampling pitch

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15
Q

equation for analog to digital conversion

A

Nyquist frequency

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16
Q

each pixel brightness value is assigned a numerical number

A

quantization

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17
Q

number of gray shades (contrast resolution)

A

pixel depth

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18
Q

Laser scanning of the exposed IP converts the released energy (_______) into an electrical signal (______)

A

visible light, voltage

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19
Q

indirect conversion utilizes a ______________ detector that converts exit radiation to _______; the __________ then converts this to a _________________

A

scintillator type, visible light, photodetector, electrical charges

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20
Q

direct conversion utilizes ____________________ detector converts exit radiation directly into ____________-

A

amorphous selenium-coated, electrical charges

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21
Q

which sends electrical signal to an analog to digital converter?

A

both direct and indirect conversion

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22
Q

solid state IRs that use a large area active matrix array of electronic components

A

flat panel detectors (FPDs)

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23
Q

for best image quality, you want _____ matrix with ______ pixel size

A

large, small

24
Q

graphic representation of a data set

A

histogram

25
Q

histogram x-axis

A

X-axis = range of pixel values

26
Q

histogram y-axis

A

y -axis = number of pixels in that range

27
Q

names for exposure indicators

A

S number, EI, Z number

28
Q

this provides a method of processing the image data, based on the reference histogram, to transform the image data into a quality image for display

A

lookup table (LUTs)

29
Q

LUTs provide the means to alter the ___________ to improve the brightness and contrast of the displayed image

A

original pixel values

30
Q

a post processing technique that can remove superimposed structures so that the anatomic area of interest becomes more visible

A

dual-energy subtraction

31
Q

post-processing technique that suppresses image noise (quantum noise)

A

smoothing

32
Q

post-processing function whereby underexposed areas (light areas) are made darker and overexposed areas (dark areas) are made lighter

A

equalization

33
Q

high-pass filtering is another term for _________

A

edge enhancement

34
Q

post-processing technique that improves the visibility of small, high-contrast structure

A

edge enhancement

35
Q

post-processing technique that reverses the grayscale from original imaging

A

inversion

36
Q

low-pass filtering is another term for __________

A

smoothing

37
Q

window level is for ________

A

brightness

38
Q

window width is for ______

A

contrast

39
Q

HIS stands for

A

hospital information system

40
Q

RIS stands for

A

radiology information system

41
Q

EHR stands for

A

electronic health record

42
Q

PACS stands for

A

picture archival and communication system

43
Q

DICOM stands for

A

digital imaging and communications in medicine

44
Q

S numbers are (inverse/direct)

A

inverse

45
Q

a larger matrix size _____ spatial resolution

A

Improves

46
Q

increasing pixel density (increases/decreases) spatial resolution

A

increases

47
Q

decreasing pixel pitch (increases/decreases) spatial resolution

A

decreases

48
Q

post processing technique that alters pixel values to change contrast

A

contrast enhancement

49
Q

what does PACS stand for?

A

pictural archival and communication system

50
Q

what does DICOM stand for?

A

Digital Imaging and Communications in Medicine

51
Q

material used in phosphor layer in CR plates

A

barium halide with europium

52
Q

material used in DR scintillator detectors

A

cesium iodide OR gadolinium oxide

53
Q

material used in DR CCD detectors

A

cesium iodide

54
Q

material used in DR CMOS detectors

A

crystalline silicon

55
Q

material used in DR direct conversion detectors

A

amorphous selenium

w.RADT 171: Fundamentals II (19 decks)

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