A histogram in digital radiography refers to:

The frequency of recorded exposure values

In digital viewing, what does Brightness mean?

The measurement of the luminance of an area in a radiographic image .

How does SID relate to receptor exposure?

as SID increases, exposure decreases

The expression of image quality provided by a detector is called:

MTF (modulation transfer function)

the smallest unit of a digital image that can be displayed on a screen

Signal to noise ratio (SNR) is the measure of ___ ?

true signal (actual anatomy) to noise (quantum motttle)

History of exposure values for this exposure ONLY

An indirect capture flat panel digital detector converts x-rays:

to light to an electronic signal

the smallest unit of data in a computer.

A detector's dynamic range is the:

ratio of maximum to minimum signal measured by the detector

Which of the following refers to automatic rescaling?

Adjusting the raw data to display the proper brightness

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Answers

1
The smallest breakdown of digital data
bit
gigabyte
megabyte
byte
2
a perfect image processing system would have an MTF of
100%
10%
1%
3
What does a photodiode do?
collect light photons
convert x-rays to light
focus the laser light
convert x-rays to electrical signal
4
What determines the wavelength of an xray?
distance
time
kilovoltage
milliamperage
5
When the radiographer selects kilovoltage on the control panel, which device is adjusted?
Rectifier circuit
Filament circuit
Autotransformer
Step-up transformer
6
In comparing various image acquisition systems, direct digital systems have the highest DQE.
False
True
7
Quantum mottle or quantum noise is a result of
undesired motion
Insufficent mAS
incorrect SID
Overpentration
8
Too much mAs will cause quantum mottle.
True
False
9
the more light spread the lower the MTF
true
false
10
A histogram in digital radiography refers to:
The number of brightness levels that can be assigned to a pixel
The frequency of recorded exposure values
11
What are 2 principle advantage of digital imaging?
pre and post processing
patient dose
there are none
time
12
The x-ray absorber used in direct capture DR is a photoconductor.
True
False
13
Image artifacts can be caused by malfunctions in the detector such as...
rotten pixels
false signal pixels
dead pixels
masking
14
In digital viewing, what does Brightness mean?
The measurement of the luminance of an area in a Matrix.
The measurement of the luminance of an area in a radiographic image .
The measurement of the luminance of an area in a pixel.
The measurement of the luminance of an area in a histogram.
15
The analog to digital converter
Determines the image matrix
All of the above
Determines the contrast resolution of the system
Makes the electrical signal understandable to the computer
16
Pixel pitch refers to the:
tone value of pixels
center of one pixel to another
size of the pixel
angle of the pixel
17
How does SID relate to receptor exposure?
SID has no effect on exposure
as SID increases, exposure decreases
as SID increases, exposure increases
as SID increases, exposure doubles
18
The expression of image quality provided by a detector is called:
SNR (signal to noise ratio)
MTF (modulation transfer function)
Matrix size
Nyquist frequency
19
Image artifacts can be caused by malfunctions in the detector such as...
rotten pixels
false signal pixels
masking
dead pixels
20
The smallest exposure change able to be captured by a detector is called:
Spatial resolution
Exposure latitude
Contrast resolution
Pixel
21
The flat-panel detector has a radiation conversion material or photoconductor typically made of
Cesium Iodide
Gadolinium oxysulfide
amorphous selenium
FET
22
What affect will a LOW Signal to Noise Ratio have on the appearance of the digital image?
Decreases spatial resolution
Decreases dynamic range
Decreases contrast resolution
Decreases Brightness
23
Spatial resolution is NOT higher with a smaller:
matrix size
DEL size
pixel size
picture element size
24
What should be done to reduce quantum mottle?
Increase mAs
Increase phosphor size
Increase kVp
Increase screen speed
25
THE ___ CONVERTS XRAY ENERGY DIRECTLY TO A DIGITAL ELECTRICAL SIGNAL
PHOTOCONDUCTOR
SCINTILLATOR
PHOTOMULTIPLIER
TLD
26
Which image has the least spatial resolution?
B
C
A
D
27
What is a pixel?
the black part of your eyeball
a German dog breed
the smallest unit of a digital image that can be displayed on a screen
the smallest type of cookie
28
Most PSP plates are made of....
gadolinium
europium barium fluorohalide
barium sulfite
silver halide
29
CsI scintillators have higher DQE than unstructured or turbid phosphors.
True
False
30
Materials that make flat panel detectors possible are:
silicon dioxide
Pixels
Amorphous silicon
Diodes
31
The ability of a digital detector to convert an X-ray exposure into a useful image is called
Pixel sampling
Detective quantum efficiency
Contrast resolution
Spatial resolution
32
Describes how digital detectors sample the xra exposure:
DEL's
pixel sample
sampling pitch
sampling frequency
33
Too much edge enhancement of the image in digital systems can cause an unwanted artifact called the:
Scaling artifact
Photoelectric effect artifact
Hounsfield artifact
Halo effect artifact
34
Signal to noise ratio (SNR) is the measure of ___ ?
true signal (actual anatomy) to noise (quantum motttle)
image detail to resolution
noise to true signal
theres no such thing
35
xray photon production occurs at the
filament
stator
anode
cathode
36
Histogram is
History of exposure values for this exposure ONLY
History of exposure values for this machine
History of exposure values for the entire hospital
37
An IP phosphor with higher DQE would require a lower mAs to produce a diagnostic image.
True
False
38
An indirect capture flat panel digital detector converts x-rays:
to an electronic signal to light
to an electronic signal
to light to an electronic signal
are sent directly to the TFT
39
A bit is
the smallest unit of data in a computer.
a keyboarding term for typing.
is a numeral system made up of 16 symbols.
a numerical label assigned to each device.
40
A detector's dynamic range is the:
amount of afterglow exhibited
ratio of maximum to minimum signal measured by the detector
number of photons absorbed by the detector
time that is required for the signal to return to zero
41
The flat-panel detector has a radiation conversion material or photoconductor typically made of
Gadolinium oxysulfide
Cesium Iodide
FET
amorphous selenium
42
The photoconductor in the direct capture FPD is:
amorphous selenium
cesium iodide
amorphous silicon
silicon chips
43
The DEL or detector element is associated with__________systems
Radiation therapy systems (RT)
Digital radiography (DR)
Computed radiography (CR)
Film/screen systems (FS)
44
Window width refers to contrast in digital imaging.
True
False
45
Which detector uses amorphous selenium
CR detector
Indirect detector
Direct detector
Film detector
46
MTF determines _____?
image density
image detail
image contrast
image size
47
What is the ideal MTF for an imaging system?
1
0
5
8
48
What is a matrix?
Number of bits that control the pixel brightness
Combination of rows or columns
A small, usually square, "picture element"
49
DQE is an acronym for:
detective quantum efficiency
detective quantum energy conductor material
direct quantum efficiency
density quantum effect
50
A digital display device with higher megapixels has better spatial resolution.
False
True
51
Which of the following refers to automatic rescaling?
Producing a histogram of the raw data
Automatically collimating to the area of interest
Converting analog to digital data
Adjusting the raw data to display the proper brightness
52
As pixel size decreases, spatial resolution...
increases
decreases
does not change
53
The type of flat panel detector that uses then films of silicon integrated with arrays of photodiodes is known as a(n) :
CsI detector
amorphous silicon detector
CMOS
charge-coupled device
54
In digital imaging, the limiting factor in spatial resolution is the
bit depth
pixel size
pixel pitch
pixel depth
55
The scintillation layer in a CCD detector is most commonly comprised of:
cesium iodide
amorphous silicon
amorphous selenium
europium activated barium fluorohalide
56
What does an MTF of 1 mean?
image produced is smaller than actual object
image produced is larger than actual object
image produced is exactly as object appears
image produced is opposite of actual image
57
A cassette-less system's detector element (DEL) size determines which of the following?
speed class
dynamic range
pixel size
detective quantum efficiency (DQE)
58
A histogram in digital radiography refers to:
The number of brightness levels that can be assigned to a pixel
The frequency of recorded exposure values
59
CRITICAL CHARACTERISTICS OF A DIGITAL IMAGE INCLUDE ALL BUT __
SAMPLE RESOLUTION
NOISE EFFICIENCY
DOSE EFFICIENCY OF THE RECEPTOR
CONTRAST RESOLUTION
60
Having a higher DQE indicates a potentially
similar patient dose
higher patient dose
lower patient dose
61
Combinations of mA and exposure time that produce a particular mAs value will produce identical receptor exposure
line-focus principle
D log E curve
reciprocity law
inverse-square law
62
Whats the description of a photoconductor?
Photoconductors aren't real
Turns power into energy
Turns e- into light
Turns light into e-
63
This reduces the size of the xray beam
Step Up transformer
Filter
Step down transformer
Collimator
64
An IP phosphor with higher DQE would require a lower mAs to produce a diagnostic image.
False
True
65
A change in the level of the window of a digital display is related to a change in:
contrast
brightness
noise level
size distortion
66
A histogram is
another name for exposure indicator value
an examination of the chest
a graphic representation of x-ray exposure
a report on exposure values
67
When a detector is unable to get rid of all the signal from a previous image this can occur.
dark shadow
image alaising
image lag
bright del
68
CCD's use _______ conversion to acquire a digital image.
indirect
direct
69
Rescaling?
amount of exposure
graphical representation of numerous shades of gray within an image
the incidence that a particular exposure value has occurred.
AKA Normalization. Re-mapping brightness and grayscale of the digital image
70
MTF is modular transfer function
True
False
71
What's the function of the flat panel thin film transistor detectors (FDP/TFT) when using direct method to produce image
Convert light to electrons
Convert x-rays to electrons
Convert x-rays to light
Converts electrons to light
72
The amount of x-ray exposure that reaches the image receptor is measured by the:
C. exposure indicator (EI)
D. signal-to-noise ratio (SNR)
B. analog-to-digital converter (ADC)
A. CCD array
73
The xray control panel must:
have an audible sound when the exposure begins and ends
All of the above
have a visible mA & kVp meter
Be located behind a protective barrier
74
True of False: A Charge-Coupled Device (CCD) converts light energy to electrical energy.
False
True
75
DQE?
Measurement that determines how efficient the IP converts photons into data
caused by low pass filtering. Reduces noise
Distance between the centers of two pixels
causes a HALO effect due to high pass filtering
76
Critical characteristics of digital image are:
Noise
Contrast resolution
All of the above
Exposure Indicators
77
TFT or FET photodiode arrays are composed of....
CeI
silicon (a-Si)
a-Se
none of these
78
The x-ray imaging system that uses a flat panel detector is
computed radiography.
film emulsion system.
direct digital radiography.
fluoroscopy.
79
Sampling and quantization are 2 processes of analog to digital conversion
True
False
80
An indirect capture flat panel digital detector converts x-rays:
to an electronic signal
are sent directly to the TFT
to an electronic signal to light
to light to an electronic signal
81
A pixel is ___.
A picture element
A fundamental unit of a digital image
A single point of color of a larger image
A smartphone made by Google
82
The range of exposures that may be captured by a detector is:
spatial frequency
contrast
spatial resolution
dynamic range
83
Indirect conversion detectors are similar to direct detectors in the they use TFT technology
true
false
84
This describes the useful imaging area of the digital receptor:
sampling frequency
FOV
detector size
pixel pitch
85
Detective Quantum Efficiency (DQE)
measurement of the percent of x-rays that is absorbed through the IR
all of the above
how efficiently a system converts the x-rays into a useful output image
High DQE produces higher quality images at a lower dose
86
Direct capture in digital radiography uses:
Scintillator & CCD
Photodetector & TFT
Photoconductor & TFT
Scintillator, Photoconductor & TFT
87
A histogram is
a report on exposure values
a graphic representation of x-ray exposure
another name for exposure indicator value
an examination of the chest
88
In flat panel detector radiography, spatial resolution is primarily controlled by the size of the:
PSP (Photostimulable Phosphor)
Focal spot
DEL (Detector Element)
TFT (Thin Film Transistor)
89
What does TFT stand for?
Thin film transitor
Thin film transistor
Think film transitor
Think film transistor
90
digital cassetteless
img resoultion is determd by pixel size of each data element
both methods use thin-flim transistor technology (TFT)
imges consists of pixel elements in a rectangular array
all are true
91
TFT or FET photodiode arrays are composed of....
none of these
a-Se
silicon (a-Si)
CeI
92
What is spatial resolution?
portion of the image forming xrays that represent anatomy
ratio of image to object as a function of spatial frequency
ability of an imaging system to render different contrasts
The ability of an imaging system to render small objects
93
In the PSP, europium is the:
activator
phosphor
scintillator
image buffer
94
Here is a flat panel detector (FTP). What does ????? do in this device?
Blocks out scattered x - rays (lead columns)
None of these. O ma ma
Completes the photo electric effect. Electrons into light
Scintillates (X - ray photons into visible)
95
define pixel
picture element
picture equation
picture elongation
picture equivalent
96
mAs controls the brightness with a digital image.
True
False
97
Which of the following is used as a photoconductor?
Gd2O2S
CsI
A-Se
A-Si:H
98
Edge enhancement and smoothing are:
global processing operations
point processing operations
geometric processing operations
local processing operations
99
what is byte
A set of privileges for allowed actions
A series of steps used to perform an action.
A series of steps used to perform an action
information in a digital computer is represented by 0 and 1s
100
What is the measure of xray absorption efficiency of an IR
DQE
SNR
LET

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