Final 1st spring Flashcards
1
Q
The test used to determine proper operation/malfunctioning of the system— should be done regularly by
A
TG 18-QC
Technologist but responsibility of medical physicists
2
Q
The German standards;document for acceptance testing is called ____the and published by ______
A
DIN 2001
By deutsches institut fur normunng
3
Q
The standard that allows medical images to be transferred through DICOM
A
GSDF
Gray scale display function
4
Q
The flat panel display measurement is a set of instructions that can be used to evaluate performance
A
VESA
5
Q
The ACR recommended these patterns for QC purposes: qualitative and quantitative
A
AAPM TG 18
6
Q
2 types of photometers
A
Near range -close to display device
Telescopic -test at 1 m distance
7
Q
The luminance response can be tested with what
A
TG 18-CT
A maximum of 171 cd
8
Q
Multiple fields on a single IP:
A discrete plot or graph :
A
Partitioning
Histogram
9
Q
A softwAre correction to equalize response of each pixel to a uniform X-ray beam
A
Flatshielding
10
Q
The process of assigning a value to a dead pixel on recorded values
A
Interpolation
11
Q
2 laws of photometry
A
Inverse
Cosine
12
Q
Luminous flux is measured by :
Measure of brightness; units of candela:
A
Candela
Nit
13
Q
Digital viewing is best done\_\_\_\_\_\_ # a gray scale that can be produced on an imaging system :
A
Straight on
Dynamic range
14
Q
X-rays that get converted to light and then to electrical signal
A
Indirect DR
CSI/CCD
15
Q
X-rays that are converted straight to electric signal
A
Direct DR
A-Se
16
Q
The lens or fiber optic that transfers X-rays to collection
A
Coupling element
17
Q
A photostimuable phosphor for DR is the
A
Capture element
18
Q
1024 bytes =
Group of 8 bits and
1024x1024
A
KB
Byte
MB
19
Q
The electronic circuitry that does computations and memory supports together is the
A
Processor
20
Q
To give the best details; we need
A
More SID, no OID, and small focal spot
21
Q
Visibility of image detail is determined by
A
Contrast resolution
22
Q
Optical Density has 2 controlling factors which are:
A
MAs and SID
23
Q
High frequency generators are used for which modalities
A
CT, mammo, portables
24
Q
The high voltage generator
3 phase 6 pulse has what percentage ripple???
And 3 phase 12 pulse?,
A
14%
4%
Full ancestry half wave are 100%
25
These are 3 steps to what?
Acceptance testing
Routine performance
Maintenance
A QC Program
26
Image interpretation, scheduling, pt preparation are all part of what program??
Quality assurance QA
27
Filtered ion chambers can be used to test what?
Kvp calliboration
28
The purpose of the autotransformer?
| Rectifier is on the high voltage side and it’s purpose is to
Kvp selector
| Convert AC to DC
29
Any mAS change is only affecting
mAS!!!!
30
Increasing or decreasing KvP affects
Contrast and density only!!!!
31
Focal spot size: increasing focal spot size will make the image
Worse!!
| It only affects detail!!!
32
The more scatter will do what to contrast
Decrease
33
The higher the grid ratio, causes density to _______ and contrast to ________
Decrease and contrast increase
34
Grids only affect
Density and contrast!!!
35
Increasing or decreasing SID has what affect on contrast??
No affect!!!!
36
The source of X-rays come from
The focal spot
37
Outer shell electrons of the filament atoms are “boiled off”
Thermionic emission
38
The protective housing around X-ray tubes contain oil to serve as an
Insulator and a cushion to dissipate heat !
39
The cathode is the negative side of the time and it contains 2 primary parts which are:,
Focusing cup
| The filament
40
Most exposure timers are controlled by a
Microprocessor
41
Electric current is
Electric potential is
Electric power
Ampere
Volts and measured in joule !!!
Watts
42
Transfer of heat from one place to another
| Transfer of energy
Convection
| Conduction
43
What is the best method is specifying X-ray quality ?,
HVL
44
Th purpose of filtration is to remove
Low energy X-rays
45
Lossless
| Lossy
Reconstructible
| Fine detail not required, video
46
#of shades of gray that an imaging system can produce
Dynamic range
47
X-rays that are converted to electric signal and uses a-Se are
Direct DR
48
X-rays that are converted to light and then to electric signal and uses CSI/CCD is
Indirect DR
49
The lens/fiber optic; piece that transfers X-ray to collection
Coupling element
50
The image plate has a lead backing to
Reduce scatter and improve contrast
51
These consist of devices that translate computer info into a form that humans can understand
Output hardware
52
Kvp varies with thickness of a part which is
2kvp/cm of part
53
Air gap acts as what grid?
| Disadvantage of OID
8:1
| Magnification and Fs blur
54
Most grid interspace material is made of what ?
Aluminum or plastic fiber
| Aluminum has less visible lines but it take more primary X-rays so Plast fiber is preferred
55
A measure of the penetrating primary and scatter X-rays through the grid (used to compare grid to non grid)
Bucky factor
56
THe advantages to compression devices
Improves spatial and contrast resolutions and decreases pt dose
57
To have quantum mottle means to have
Not enough mAs
58
The bigger the object; the _______ distortion
More
59
2 things affect magnificAtion
OID
| sID
60
X-rays that exit the pt and interact with the Image receptor
Image forming X-rays
61
As scatter increases , the image loses
Contrast
62
The 3 scatter factors
Part thickness, kvp, and fold size
63
The atomic # for bone
The atomic # tissue
The atomic # iodine m barium
13
7.4
53 & 56
64
Differential absorption occurs when X-rays
Are transmitted thru the pt
| Photoelectrically absorbed
65
X-rays that are transmitted thru the patient are
| Radiopaque OR radiolucent
Radiolucent
66
Compton scattering is only partially
Absorbed
67
No energy transfer or ionization but causes noise on image
Coherent
| Lowers contrast on image (more shades of gray
68
Incident X-rays interact with the outer shell electron and ejects it; ionizing the atom
Compton
69
Inner shell electrons & is total absorption
Photoelectric
70
After photoelectric interaction: ejection of K shell gives a vacancy when the outer shell L takes its place is called
Characteristic X-rays
| Which only occurs at 69-70kvp!
71
Annihilation occurs above 1.02 meV (this interact room occurs on PET scans)
Pair production
72
The glass or metal enclosure of X-ray tube filters beam
Inherent filtration
73
A thin sheet of AL between protective tube housing and X-ray beam collimator
Added filtration
74
A way of increasing high energy X-rays and removing low energy X-rays is called
X-ray beam hardening
75
X-rays at any given energy are more penetrating in material with high or low atomic #s
Low atomic #
76
The process of the image intensifir:
X-rays photons
Light photons
Electrons
Back to light
77
Ration of The # of light photons at the output phosphor over the # of Xrays at the input phosphor
Flux gain
78
Ability of II to increase the illumination level of the image
Min gainXflux gain
Brightness gain
79
1 X-ray can create ______ light photons
3000
80
The photocathode in the image intensifier emits
Electrons!!
81
```
Parts of the eye :
Iris
Cornea
Retina
Fovea centralis
```
Diaphragm
Protective layer
Rods n cones
Center of eye
82
Dynamic process that are sometimes dim so it requires illumination (image intensifier)
Fluoroscopy
83
Who invented flouroscopy?
Thomas Edison
84
X-rays that exits the patient are incident on the II tube are transmitted thru the glass envelope & interact with the
Input phosphor
| Which is CSI (cesium iodide)
85
When X-rays interact with the input phosphor of the II, it’s energy is converted to
Light
86
Electron emission that follows light stimulation
Photoemission
87
The photocathode emits electrons when illuminated by the input phosphor; this is called
Photoemission
88
This would occur from continuous synergies exposures & pt dose would be high!
Thermal overloading
89
Who endorsed Th “pause and pulse” and was adopted by image gently
Image wisely
90
2 image receptors used for digital flouro
CCD and flat panel
91
Method of temporal subtraction that results in successive subtraction images of contrast filled vessels
Mask mode
92
The devices used to test focal spot ?
The device used to test collimation?
Star, slit, pinhole
| PBL (semi annually 2%)
93
The image forming X-rays hit the IR and creates the invisible
Latent image
94
Image contrast on the image formation in flouro is improved with
Subtraction techniques
95
The video system used in conventional flouro uses
525 line system
96
Background electronic noise
Is similar to image fog in digital- obscures electronic signal(reduces contrast)
97
Process by which very high energy X-rays can escape with electrons; the nuclear electric field and can be directly absorbed by nucleus
Photodisintegration
98
Interaction between the X-ray and the nuclear field that causes the X-ray to disappear and 2 electrons (one positive, one negative) to take its place
Pair Production
99
Geometric unsharpness; image blur that occurs from the size of the focal spot
Penumbra
100
Electron in the outermost shell
Valence electron
101
Electronic vacuum tube that amplified a flouro image to reduce pt dose
Image intensifier
102
Can be reconstructed like original
When fine details not required
100:1 compression factor
Lossless
Lossy (not used for mammo)
103
Emission of electrons from the photocathode
Photoemission
104
What conversion occurs in the image at the input phosphor of the II
X-rays converted to visible light
105
Which conversion occurs in the Image at the photocathode of the II
Light is converted to electrons
106
Which conversion occurs in the image at the output phosphor of an II
Electrons are converted to visible light
107
Which comes 1st in II fluoroscopy ?
Cesium iodide screen
108
Which component of the tv monitor transfers the video signal into a visible image ?
Fluorescent screen
109
What would not be found in the interspaces of a grid
Lead!
110
The image after processing is known as the
Manifest image
111
How far from The IR would we practice moving the patient for OID
10-15cm
112
Feature on a flouroscope That allows the radiologist to select image brightness that is maintained automatically
ABC
| Automatic brightness control
113
X-ray that r suite from interaction of the projectile electron with a target nucleus, braking radiation
Brems X-ray
114
Electron beam tube that designed for a 2 dimensional display view
Cathode ray tube
115
Negative side of the X-ray tube
| Contains filament and focusing cup
Cathode side
116
Solid state device that converts light to electrons
Charge couple device
117
Recording of flouro image on movie film
Cineflouragraphy
118
Percentage of X-rays absorbed by the IR
DQE
119
Standard that enables imaging systems to communicate
DICOM
120
Part of the cathode that emits electrons, resulting in tube current :
Metal shroud that surrounds the filament:
Filament
| Focusing cup
121
Absence of optical density on a radiograph caused by unintended X-ray absorption in a grid
Grid cutoff
122
Deterioration of the radiograph image
Image noise
123
Electron cloud from the filament
Space charge
124
Television camera tube that is used most often in Tv flouro:
| Reduction of brightness in the periphery
Vidicon
| Vignetting
125
The___________ mode of reading the digital signal produces a sharper image with less flicker
Progressive
125
The output signal from The II digital image is transmitted to an analog-digital converter
ADC
126
When using s 1024x1024 matrix mode is being used than ___ images can be transferred per second
8
127
Two subtraction techniques; temporal and energy subtractions used in flouro together is called
Hybrid subtraction
128
subtracted images from a different mask and follow up frame
TID
| Time interval difference
129
Energy subtraction -
Temporal subtraction -
Rapid kvp, complex image subtraction
| Single kvp, simple subtraction
130
Conventional line system has _____ lines
| Digital 1024x1024 has _____ line system
525
| 1000
131
Th federal law and most states under normal flouro the ESD should not exceed
10 R/min
132
Th entrance skin dose (ESD) for an adult during flour on average is
3-5 R/min
133
Th horizontal resolution in video monitoring is determined by the
Bandpass
| The higher the better
134
The _____ is a heater filament that supplies constant electron current by thermionic emission
Electron gun
135
Use of a smaller dimension of a multifield II tube results in
A magnified image!
136
The ability to perceive fine detail is called
Visual acuity
137
This timer will terminate after 6 s
Guard timer
138
Reduction in contrast in the II
Veiling glare
