問題一覧
1
The ability to accurately covert absorbed x-ray signal to electrical signal
conversion efficiency
2
The product of geometric, quantum and conversion efficiency
overall/dose efficiency
3
Dose efficiency normal value
0.45-0.85
4
Refers to the steadiness of the detector response.
stability
5
Refers to the speed with which the detector can detect an x-ray event and recover to detect another event.
response time
6
Ratio of the largest signal to be measured to the precision of the smallest signal to be discriminated.
dynamic range
7
Detector thas has ionization of gas
gas filled
8
3 types of gas filled
proportional counter, ionization chamber, geiger muller counter
9
Characteristics of gas filled
excellent stability, large dynamic range, low quantum efficiency
10
Characteristics of scintillation detector
high x-ray detection efficiency, allows faster imaging time, improves image quality
11
Crystal use in scintillation detector
sodium iodide
12
Siodium iodide is replace by
bismuth germanate, cesium iodide
13
Current/common crystal of use in scintillation
cadnium tungstate, special ceramic (gadolinium oxysulfide)
14
Crystal converts incident xray to light
solid state detector
15
Converts light into electrical signal
photodiode semiconductor
16
Characteristics of photodiode
small, cheap, doesn't require power supply
17
The alternative detector concept
flat panel detector
18
Potential advantages are the possibility to scan with wider cone angles without the need to develop detectors with 1024 rows or more and the high spatial resolution, particularly in medium to large field of view scans.
flat panel detector
19
Potential advantages are the possibility to scan with wider cone angles without the need to develop detectors with how many rows or more and the high spatial resolution, particularly in medium to large field of view scans.
1024
20
were developed for digital radiography and their use for CT is currently being explored by manufacturers.
flat panel detector
21
Groupings of detectors
plug in detector
22
Each detector modules “plugs” into the mother board unit of the detector system.
plug in detector
23
Each detector modules “plugs” into the what of the detector system.
mother board unit
24
Helps to maintain the integrity of the CT detector system through easy testing and replacement procedures
plug in detector
25
Faster volume coverage.
dual slice/dual row detector
26
Consists of dual-row, solid state detector array coupled with a special type of x-ray tube based on double-dynamic focus system.
dual slice/dual row detector
27
Thinner slices, longer scan volumes, faster scan volumes
multi slice/multi row detector
28
A typical acquisition with a single detector row scanner covered?
5 mm
29
Ct scanners with 4 active detector rows achieved a?
substantial improvement of the longitudinal resolution
30
By using 4 active detector rows in a 4x1 acquisition configuration, the longitudinal spatial resolution improve from
5 mm to 1 mm
31
Detector sizes are the effective size at the what
isocenter
32
These are effective size at the isocenter
detector sizes
33
Detector sized are the what at the isocenter
effective size
34
The minimum number of detector element should be approximately
(2 fov)/d
35
(2 fov)/d to achieve spatial resolution of?
d
36
How many detector elements are required to achieve a special resolution of 1 mm within a reconstructed image at a field of view of 400 mm
800
37
800 detector elements are required to achieve a special resolution of how many within a reconstructed image at a field of view of 400 mm
1 mm
38
800 detector elements are required to achieve a special resolution of 1 mm within a reconstructed image at a field of view of what?
400 mm
39
Spatial resolution can be improved by use of the
quarter detector shift
40
Special resolution can also be improved by the use of a
dynamic focal spot
41
By shifting the detector elements by a distance of a quarter of the size of the detector elements the theoretical achievable special resolution becomes twice as good
quarter detector shift
42
By shifting the detector elements by a distance of a quarter of the size of the detector elements the theoretical achievable special resolution becomes how many as good
twice
43
It is generally implemented in detectors of all ct scanners
quarter detector shift
44
Focal spot position on anode is rapidly oscillated during country rotation doubling the number of projections
dynamic focal spot
45
Focal spot position on anode is rapidly oscillated during country rotation making what the number of projections
doubling
46
With the current detector rows and/or quarter detector shift and/or flying vocal spot a special resolution of how many in the axial plane can be achieved
~0.6-0.9
47
Computer controlled electronic amplifier and switching device
data acquisition system
48
This is where signal from each radiation detector is connected
data acquisition system
49
Das consist mainly of
preamplifier, integrator, multiplexer, logarithmic, amplifier, adc
50
Contains meters and controls
control console
51
Fpr selection of proper imaging technique factors
control console
52
For proper mechanical movement of the gantry and patient couch
control console
53
How many operating consoles are available
2-3
54
How many operating consoles for radiologic technologist
2
55
How many operating consoles for physician
1
56
Allows the operator to view the resulting image before transferring it to hard copy.
monitor
57
Unique subsystem of the CT imaging system
computer
58
heart of the computer that determines the reconstruction time.
microprocessor, primary memory
59
Special type of computer processor which is widely used in CT instead of microprocessors.
array processor
60
Computer memories
rom, ram
61
Performs calculations and logical operations under control of software instruction.
cpu
62
Cpu Performs calculations and logical operations under control of what
software instruction
63
Cpu Performs what under control of software instruction.
calculation, logical operation
64
Special requirements in control console
controlled environment, <30% humidity, <20°C temperature, reconstruction time is 1 second and less
65
Scan power : typical values for the maximum power are
20/40-100 KW w/ high voltage ~80-100kV
66
Focal spots : X - ray tubes use typical focal spot
0.5-1.2 mm
67
Specific innovations for CT are the ‘ what’ allowing for control of the focus position on the anode during the scan or the electromagnetic control of the electron beam, which allows switching of the focal spot position both in the fan and in the Z - direction, providing overlapping sampling.
flying focus
68
Rotation speed : the traditional glass tube technology is not adequate in terms of required precision and stability to sustain the very high rotation speed, up to how many, of high - performance tubes
10500 rotation/min
69
Despite its higher thermic dissipation and lower cost, glass has been replaced by the what, which is more precise and better able to sustain the constraints related to the rotation speed
metal ceramic technology
70
It was the main way used for three decades. This approach consists of an increase in the thermal capacity of the anode by increasing its diameter and mass. This system has obvious limitations, as it still uses radiative cooling.
brute force approach
71
It is based on a slow evolution in the materials used for the anode.
material approach
72
Use of circular grooves in the anode support to increase the contact and improve cooling.
direct cooling
73
Use of special liquid metal vacuum bearings that allow faster anode rotation.
direct cooling
74
Focal track made of a mixture of rhenium and tungsten. Rhenium has a higher linear expansibility than tungsten and slows the rate at which anode crazing occurs
direct cooling
75
Use of what in the anode support to increase the contact and improve cooling.
circular groove
76
Use of whatthat allow faster anode rotation.
special liquid metal vacuum bearings
77
Focal track made of a mixture of what. Rhenium has a higher linear expansibility than tungsten and slows the rate at which anode crazing occurs
tungsten, rhenium
78
Rhenium has a what than tungsten and slows the rate at which anode crazing occurs
high linear expansibility
79
Anode ‘ compound ’ /increased thermal capacities: use of molybdenum or graphite with tungsten in the anode disk. Molybdenum has twice the specific heat capacity and half the density of tungsten. Graphite has an even higher specific heat capacity and a quarter of the density of molybdenum. It increases thermal capacity.
direct cooling
80
Anode ‘ compound ’ /increased thermal capacities: use of what in the anode disk. Molybdenum has twice the specific heat capacity and half the density of tungsten. Graphite has an even higher specific heat capacity and a quarter of the density of molybdenum. It increases thermal capacity.
molybdenum/graphite w/ tungsten
81
Replacement of the ball bearings by a liquid metal (gallium) that allows the evacuation of heat by conduction.
direct cooling
82
Replacement of the ball bearings by a what that allows the evacuation of heat by conduction.
liquid metal (gallium)
83
reduction of the heat produced via reduced scan duration by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to 1000 rows.
indirect cooling
84
reduction of the heat produced via what by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to 1000 rows.
reduce scan duration
85
reduction of the heat produced via reduced scan duration by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to how many rows
1000
86
The ‘ paradigm shift ’ corresponds to innovations in X - ray tubes.
indirect cooling
87
It corresponds to innovations in X - ray tubes.
paradigm shift
88
Who developed the Straton tube, also called the rotating envelope tube
Siemens
89
Siemens developed the what, also called the rotating envelope tube
straton tube
90
Siemens developed the Straton tube, also called the
rotating envelope tube
91
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
indirect cooling
92
This tube uses direct convective cooling, exclusively of the anode, with a what at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow
cooling oil stream
93
This tube uses direct what, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
convective cooling
94
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to how many MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
4.8 mhu/min
95
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing what due to anode cooling in the clinical workflow.
waiting times
96
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for what of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
large heat storage capacity
97
Layout of cells in rows and columns
image matrix
98
Original EMI
80x80 matrix
99
Current system (emi)
512x512 matrix
100
Each cell of information
pixel
projection
projection
Shanks Redhaired · 7問 · 1年前projection
projection
7問 • 1年前IR
IR
Shanks Redhaired · 66問 · 1年前IR
IR
66問 • 1年前ct midterm
ct midterm
Shanks Redhaired · 100問 · 1年前ct midterm
ct midterm
100問 • 1年前ct midterm 3
ct midterm 3
Shanks Redhaired · 41問 · 1年前ct midterm 3
ct midterm 3
41問 • 1年前part 1
part 1
Shanks Redhaired · 24問 · 1年前part 1
part 1
24問 • 1年前ct
ct
Shanks Redhaired · 6問 · 1年前ct
ct
6問 • 1年前CT I
CT I
Shanks Redhaired · 100問 · 1年前CT I
CT I
100問 • 1年前CT II
CT II
Shanks Redhaired · 35問 · 1年前CT II
CT II
35問 • 1年前Mammography Finals
Mammography Finals
Shanks Redhaired · 60問 · 1年前Mammography Finals
Mammography Finals
60問 • 1年前FINAL RADTHERA
FINAL RADTHERA
Shanks Redhaired · 95問 · 1年前FINAL RADTHERA
FINAL RADTHERA
95問 • 1年前FINAL II RADTHERA
FINAL II RADTHERA
Shanks Redhaired · 89問 · 1年前FINAL II RADTHERA
FINAL II RADTHERA
89問 • 1年前radthera
radthera
Shanks Redhaired · 95問 · 1年前radthera
radthera
95問 • 1年前Angiocardiography
Angiocardiography
Shanks Redhaired · 94問 · 1年前Angiocardiography
Angiocardiography
94問 • 1年前fluoroscopy
fluoroscopy
Shanks Redhaired · 100問 · 1年前fluoroscopy
fluoroscopy
100問 • 1年前fluoroscopy 2
fluoroscopy 2
Shanks Redhaired · 100問 · 1年前fluoroscopy 2
fluoroscopy 2
100問 • 1年前問題一覧
1
The ability to accurately covert absorbed x-ray signal to electrical signal
conversion efficiency
2
The product of geometric, quantum and conversion efficiency
overall/dose efficiency
3
Dose efficiency normal value
0.45-0.85
4
Refers to the steadiness of the detector response.
stability
5
Refers to the speed with which the detector can detect an x-ray event and recover to detect another event.
response time
6
Ratio of the largest signal to be measured to the precision of the smallest signal to be discriminated.
dynamic range
7
Detector thas has ionization of gas
gas filled
8
3 types of gas filled
proportional counter, ionization chamber, geiger muller counter
9
Characteristics of gas filled
excellent stability, large dynamic range, low quantum efficiency
10
Characteristics of scintillation detector
high x-ray detection efficiency, allows faster imaging time, improves image quality
11
Crystal use in scintillation detector
sodium iodide
12
Siodium iodide is replace by
bismuth germanate, cesium iodide
13
Current/common crystal of use in scintillation
cadnium tungstate, special ceramic (gadolinium oxysulfide)
14
Crystal converts incident xray to light
solid state detector
15
Converts light into electrical signal
photodiode semiconductor
16
Characteristics of photodiode
small, cheap, doesn't require power supply
17
The alternative detector concept
flat panel detector
18
Potential advantages are the possibility to scan with wider cone angles without the need to develop detectors with 1024 rows or more and the high spatial resolution, particularly in medium to large field of view scans.
flat panel detector
19
Potential advantages are the possibility to scan with wider cone angles without the need to develop detectors with how many rows or more and the high spatial resolution, particularly in medium to large field of view scans.
1024
20
were developed for digital radiography and their use for CT is currently being explored by manufacturers.
flat panel detector
21
Groupings of detectors
plug in detector
22
Each detector modules “plugs” into the mother board unit of the detector system.
plug in detector
23
Each detector modules “plugs” into the what of the detector system.
mother board unit
24
Helps to maintain the integrity of the CT detector system through easy testing and replacement procedures
plug in detector
25
Faster volume coverage.
dual slice/dual row detector
26
Consists of dual-row, solid state detector array coupled with a special type of x-ray tube based on double-dynamic focus system.
dual slice/dual row detector
27
Thinner slices, longer scan volumes, faster scan volumes
multi slice/multi row detector
28
A typical acquisition with a single detector row scanner covered?
5 mm
29
Ct scanners with 4 active detector rows achieved a?
substantial improvement of the longitudinal resolution
30
By using 4 active detector rows in a 4x1 acquisition configuration, the longitudinal spatial resolution improve from
5 mm to 1 mm
31
Detector sizes are the effective size at the what
isocenter
32
These are effective size at the isocenter
detector sizes
33
Detector sized are the what at the isocenter
effective size
34
The minimum number of detector element should be approximately
(2 fov)/d
35
(2 fov)/d to achieve spatial resolution of?
d
36
How many detector elements are required to achieve a special resolution of 1 mm within a reconstructed image at a field of view of 400 mm
800
37
800 detector elements are required to achieve a special resolution of how many within a reconstructed image at a field of view of 400 mm
1 mm
38
800 detector elements are required to achieve a special resolution of 1 mm within a reconstructed image at a field of view of what?
400 mm
39
Spatial resolution can be improved by use of the
quarter detector shift
40
Special resolution can also be improved by the use of a
dynamic focal spot
41
By shifting the detector elements by a distance of a quarter of the size of the detector elements the theoretical achievable special resolution becomes twice as good
quarter detector shift
42
By shifting the detector elements by a distance of a quarter of the size of the detector elements the theoretical achievable special resolution becomes how many as good
twice
43
It is generally implemented in detectors of all ct scanners
quarter detector shift
44
Focal spot position on anode is rapidly oscillated during country rotation doubling the number of projections
dynamic focal spot
45
Focal spot position on anode is rapidly oscillated during country rotation making what the number of projections
doubling
46
With the current detector rows and/or quarter detector shift and/or flying vocal spot a special resolution of how many in the axial plane can be achieved
~0.6-0.9
47
Computer controlled electronic amplifier and switching device
data acquisition system
48
This is where signal from each radiation detector is connected
data acquisition system
49
Das consist mainly of
preamplifier, integrator, multiplexer, logarithmic, amplifier, adc
50
Contains meters and controls
control console
51
Fpr selection of proper imaging technique factors
control console
52
For proper mechanical movement of the gantry and patient couch
control console
53
How many operating consoles are available
2-3
54
How many operating consoles for radiologic technologist
2
55
How many operating consoles for physician
1
56
Allows the operator to view the resulting image before transferring it to hard copy.
monitor
57
Unique subsystem of the CT imaging system
computer
58
heart of the computer that determines the reconstruction time.
microprocessor, primary memory
59
Special type of computer processor which is widely used in CT instead of microprocessors.
array processor
60
Computer memories
rom, ram
61
Performs calculations and logical operations under control of software instruction.
cpu
62
Cpu Performs calculations and logical operations under control of what
software instruction
63
Cpu Performs what under control of software instruction.
calculation, logical operation
64
Special requirements in control console
controlled environment, <30% humidity, <20°C temperature, reconstruction time is 1 second and less
65
Scan power : typical values for the maximum power are
20/40-100 KW w/ high voltage ~80-100kV
66
Focal spots : X - ray tubes use typical focal spot
0.5-1.2 mm
67
Specific innovations for CT are the ‘ what’ allowing for control of the focus position on the anode during the scan or the electromagnetic control of the electron beam, which allows switching of the focal spot position both in the fan and in the Z - direction, providing overlapping sampling.
flying focus
68
Rotation speed : the traditional glass tube technology is not adequate in terms of required precision and stability to sustain the very high rotation speed, up to how many, of high - performance tubes
10500 rotation/min
69
Despite its higher thermic dissipation and lower cost, glass has been replaced by the what, which is more precise and better able to sustain the constraints related to the rotation speed
metal ceramic technology
70
It was the main way used for three decades. This approach consists of an increase in the thermal capacity of the anode by increasing its diameter and mass. This system has obvious limitations, as it still uses radiative cooling.
brute force approach
71
It is based on a slow evolution in the materials used for the anode.
material approach
72
Use of circular grooves in the anode support to increase the contact and improve cooling.
direct cooling
73
Use of special liquid metal vacuum bearings that allow faster anode rotation.
direct cooling
74
Focal track made of a mixture of rhenium and tungsten. Rhenium has a higher linear expansibility than tungsten and slows the rate at which anode crazing occurs
direct cooling
75
Use of what in the anode support to increase the contact and improve cooling.
circular groove
76
Use of whatthat allow faster anode rotation.
special liquid metal vacuum bearings
77
Focal track made of a mixture of what. Rhenium has a higher linear expansibility than tungsten and slows the rate at which anode crazing occurs
tungsten, rhenium
78
Rhenium has a what than tungsten and slows the rate at which anode crazing occurs
high linear expansibility
79
Anode ‘ compound ’ /increased thermal capacities: use of molybdenum or graphite with tungsten in the anode disk. Molybdenum has twice the specific heat capacity and half the density of tungsten. Graphite has an even higher specific heat capacity and a quarter of the density of molybdenum. It increases thermal capacity.
direct cooling
80
Anode ‘ compound ’ /increased thermal capacities: use of what in the anode disk. Molybdenum has twice the specific heat capacity and half the density of tungsten. Graphite has an even higher specific heat capacity and a quarter of the density of molybdenum. It increases thermal capacity.
molybdenum/graphite w/ tungsten
81
Replacement of the ball bearings by a liquid metal (gallium) that allows the evacuation of heat by conduction.
direct cooling
82
Replacement of the ball bearings by a what that allows the evacuation of heat by conduction.
liquid metal (gallium)
83
reduction of the heat produced via reduced scan duration by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to 1000 rows.
indirect cooling
84
reduction of the heat produced via what by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to 1000 rows.
reduce scan duration
85
reduction of the heat produced via reduced scan duration by a factor approximately equivalent to the number of rows. Manufacturers developed systems with up to how many rows
1000
86
The ‘ paradigm shift ’ corresponds to innovations in X - ray tubes.
indirect cooling
87
It corresponds to innovations in X - ray tubes.
paradigm shift
88
Who developed the Straton tube, also called the rotating envelope tube
Siemens
89
Siemens developed the what, also called the rotating envelope tube
straton tube
90
Siemens developed the Straton tube, also called the
rotating envelope tube
91
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
indirect cooling
92
This tube uses direct convective cooling, exclusively of the anode, with a what at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow
cooling oil stream
93
This tube uses direct what, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
convective cooling
94
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to how many MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
4.8 mhu/min
95
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for large heat storage capacities of the anode disk and reducing what due to anode cooling in the clinical workflow.
waiting times
96
This tube uses direct convective cooling, exclusively of the anode, with a cooling oil stream at the anode ’ s back surface. As a result, the cooling rate is vastly increased to 4.8 MHU/min, eliminating the need for what of the anode disk and reducing waiting times due to anode cooling in the clinical workflow.
large heat storage capacity
97
Layout of cells in rows and columns
image matrix
98
Original EMI
80x80 matrix
99
Current system (emi)
512x512 matrix
100
Each cell of information
pixel