Equipment Operation & Quality Control Flashcards
(119 cards)
1
Q
All the following are associated with the anode except
(A) the line-focus principle
(B) the heel effect
(C) the focal track
(D) thermionic emission All the following are associated with the anode except
A
Thermionic Emission
2
Q
The type of x-ray tube designed to turn on and off rapidly, providing multiple short, precise exposures, is
(A) high speed
(B) grid-controlled
(C) diode
(D) electrode
A
grid-controlled
3
Q
Typical examples of digital imaging include
- MRI
- CT
- CR
A
1,2 & 3
4
Q
Component parts of a CT gantry include
- high-voltage generator
- multidetector array
- x-ray tube
A
1,2 & 3
5
Q
Which of the following circuit devices operate(s) on the principle of selfinduction?
- Autotransformer
- Choke coil
- High-voltage transformer
A
1 & 2 only
6
Q
If exposure factors of 85 kV , 400 mA, and 12 ms yield an output exposure of 150 mR, what is the milliroentgens per milliampere-seconds (mR/mAs)?
A
31
7
Q
If a high-voltage transformer has 100 primary turns and 50,000 secondary turns and is supplied by 220 V and 100 A, what are the secondary voltage and current?
A
200 mA and 110 kV
8
Q
how many voltage ripple for full wave rectification
A
100% voltage ripple
9
Q
When using the smaller field in a dual-field image intensifier,
- the image is magnified
- the image is brighter
- a larger anatomic area is viewed
A
1 only
10
Q
The minimum response time of an automatic exposure control (AEC)
A
is its shortest possible exposure time
11
Q
Functions to protect the patient from overexposure and the x-ray tube from overload
A
Back up timer
12
Q
The electron cloud within the x-ray tube is the product of a process called
A
Thermionic Emission
13
Q
Which of the following causes pitting, or many small surface melts, of the anode’s focal track?
A
Repeated frequent overloading
14
Q
Which of the following is (are) characteristics of the x-ray tube?
- The target material should have a high atomic number and a high melting point.
- The useful beam emerges from the port window.
- The cathode assembly receives both low and high voltages.
A
1,2 & 3
15
Q
A parallel-plate ionization chamber receives a particular charge as x-ray photons travel through it. This is the operating principle of which of the following devices?
(A) AEC
(B) Image intensifier
(C) Cine-film camera
(D) Spot-film camera
A
AEC
16
Q
Which of the following will serve to increase the effective energy of the x-ray beam?
- Increase in added filtration
- Increase in kilovoltage
- Increase in milliamperage
A
1 & 2 only
17
Q
Which of the following combinations would pose the least hazard to a particular anode?
(A) 1.2-mm focal spot, 92 kV , 1.5 mAs
(B) 0.6-mm focal spot, 80 kV , 3 mAs
(C) 1.2-mm focal spot, 70 kV , 6 mAs
(D) 0.6-mm focal spot, 60 kV , 12 mAs
A
(A) 1.2-mm focal spot, 92 kV , 1.5 mAs
18
Q
Functions to direct the liberated filament electrons to the focal spot.
A
Molybdenum Focusing Cup
19
Q
Congruence of the x-ray beam with the light field is tested using
A
Radio opaque objects
20
Q
Delivery of large exposures to a cold anode or the use of exposures exceeding tube limitation can result in
- increased tube output
- cracking of the anode
- rotor-bearing damage
A
2 & 3 only
21
Q
If the primary coil of a high-voltage transformer is supplied by 220 V and has 400 turns and the secondary coil has 100,000 turns, what is the voltage
induced in the secondary coil?
A
55 kV
22
Q
What is the relationship between kV and HVL?
A
As kV increases, the HVL increases.
23
Q
As window level increases
A
brightness increases
24
Q
Which of the following is/are components of the secondary, or high voltage, side of the x-ray circuit?
- Rectification system
- Autotransformer
- kV meter
A
1 only
25
Patient dose during fluoroscopy is affected by the
1. distance between the patient and the input phosphor 2. amount of magnification
3. tissue density
1,2 & 3
26
A backup timer for the AEC serves to
1. protect the patient from overexposure
2. protect the x-ray tube from excessive heat
3. increase or decrease master density
1 & 2 only
27
```
Which of the following devices converts electrical energy to mechanical energy?
(A) Motor
(B) Generator
(C) Stator
(D) Rotor
```
motor
28
The essential function of a phototimer is to
terminate the x-ray exposure once the IR is correctly exposed
29
A slit camera is used to measure
1. focal-spot size
2. spatial resolution
3. intensifying-screen resolution
1 & 2 only
30
In which of the following examinations would an IP front with very low absorption properties be especially important?
Mammography
31
Which of the following will improve the spatial resolution of image intensified images?
1. A very thin coating of cesium iodide on the input phosphor
2. A smaller-diameter input screen
3. Increased total brightness gain
1 and 2 only
32
The advantages of collimators over aperture diaphragms and flare cones include
1. the variety of field sizes available
2. more efficient beam restriction
3. better cleanup of scattered radiation
1 and 2 only
33
Which of the following occurs during Bremsstrahlung (Brems) radiation production?
(A) An electron makes a transition from an outer to an inner electron shell.
(B) An electron approaching a positive nuclear charge changes direction and loses energy.
(C) A high-energy photon ejects an outer-shell electron.
(D) A low-energy photon ejects an inner-shell electron.
An electron approaching a positive nuclear charge changes direction and loses energy.
34
Characteristics of the metallic element tungsten include
1. ready dissipation of heat
2. high melting point
3. high atomic number
1, 2, and 3
35
The voltage ripple associated with a three-phase, six-pulse rectified generator is about
13% voltage ripple
36
The device that receives the remnant beam, converts it into light, and then increases the brightness of that light is the
image intensifier
37
A high-speed electron entering the tungsten target is attracted to the positive nucleus of a tungsten atom and, in the process, is decelerated. This results in
Bremstrahlung Radiation
38
All the following are components of the image intensifier except
(A) the photocathode
(B) the focusing lenses
(C) the TV monitor
(D) the accelerating anode
TV monitor
39
Components of digital imaging include
1. computer manipulation of the image
2. formation of an electronic image on the radiation detector
3. formation of an x-ray image directly on the IR
1 and 2 only
40
Which of the following is used in digital fluoroscopy, replacing the image intensifier’s television camera tube?
(A) Solid-state diode
(B) Charge-coupled device
(C) Photostimulable phosphor
(D) Vidicon
Charge-coupled device
41
A three-phase timer can be tested for accuracy using a synchronous spinning top. The resulting image looks like a
solid arc, with the angle (in degrees) representative of the exposure time
42
The regular measurement and evaluation of radiographic equipment components and their performance is most accurately termed as
Quality Control
43
The procedure whose basic operation involves reciprocal motion of the x-ray tube and film is
Tomography
44
In fluoroscopy, the automatic brightness control is used to adjust the
kilovoltage (kV) and milliamperage (mA)
45
When the radiographer selects kilovoltage on the control panel, which device is adjusted?
Autotransformer
46
Star and wye configurations are related to
three-phase transformers
47
What is the device that directs the light emitted from the image intensifier to various viewing and imaging apparatus?
Beam splitter
48
As electrons impinge on the anode surface, less than 1% of their kinetic energy is changed to
xrays
49
Which of the following contribute(s) to inherent filtration?
1. X-ray tube glass envelope
2. X-ray tube port window
3. Aluminum between the tube housing and the collimator
1 and 2 only
50
A quality-control (QC) program includes checks on which of the following radiographic equipment conditions?
1. Reproducibility
2. Linearity
3. Positive beam limitation/automatic collimation
1, 2, and 3
51
Means that repeated exposures at a given technique must provide consistent intensity
Reproducibility
52
Means that a given milliampere-seconds value, using different milliamperage stations with appropriate exposure time adjustments, will provide consistent intensity
Linearity
53
The two components of an induction motor—whose function it is to rotate the anode
Stator
| Rotor
54
Characteristics of x-ray photons include
1. a penetrating effect on all matter
2. an ionizing effect on air
3. travelling at the speed of sound
1 and 2 only
55
All the following x-ray circuit devices are located between the incoming power supply and the primary coil of the high-voltage transformer except
(A) the timer
(B) the kilovoltage meter
(C) the milliamperage meter
(D) the autotransformer
(C) the milliamperage meter
56
Which of the following systems function(s) to compensate for changing patient/part thicknesses during fluoroscopic procedures?
(A) Automatic brightness control
(B) Minification gain
(C) Automatic resolution control
(D) Flux gain
(A) Automatic brightness control
57
Minification and flux gain contribute to
total brightness gain
58
Disadvantages of moving grids over stationary grids include which of the following?
1. They can prohibit the use of very short exposure times.
2. They increase patient radiation dose.
3. They can cause phantom images when anatomic parts parallel their motion.
1 and 2 only
59
The functions of a picture archiving and communication system (PACS) include
1. storage of analog images
2. acquisition of digital images
3. storage of digital images
2 and 3 only
60
How many half-value layers will it take to reduce an x-ray beam whose intensity is 78 R/min to an intensity of less than 10 R/min?
3
61
The kV settings on radiographic equipment must be tested annually and must be accurate to within
+/–4 kV
62
An incorrect relationship between the primary beam and the center of a focused grid results in
1. an increase in scattered radiation production
2. grid cutoff
3. insufficient radiographic density
2 and 3 only
63
The x-ray tube in a CT imaging system is most likely to be associated with
a pulsed x-ray beam
64
Is used to test the timer efficiency of full-wave-rectified single-phase equipment.
Spinning top
65
Conditions that contribute to x-ray tube damage include
1. lengthy anode rotation
2. exposures to a cold anode
3. low-milliampere-seconds/high-kilovoltage exposure factors
1 and 2 only
66
The total brightness gain of an image intensifier is the product of
1. flux gain
2. minification gain
3. focusing gain
1 and 2 only
67
The ratio of the number of x-ray photons at the input phosphor compared to the number light photons at the output phosphor is termed
flux gain
68
Which of the following information is necessary to determine the maximum safe kilovoltage using the appropriate x-ray tube rating chart?
1. Milliamperage and exposure time
2. Focal-spot size
3. Imaging-system speed
1 and 2 only
69
A spinning-top device can be used to evaluate
1. timer accuracy
2. rectifier failure
3. the effect of kilovoltage on contrast
1 and 2 only
70
A device used to ensure reproducible radiographs, regardless of tissuedensity variations, is the
automatic exposure control
71
The device used to change alternating current to unidirectional current is
a solid-state diode
72
In order for the projected light beam to be the same size as the x-ray beam, the focal spot and the light bulb must be
exactly the same distance from the center of the mirror
73
To maintain image clarity in an image-intensifier system, the path of electron flow from the photocathode to the output phosphor is controlled by
electrostatic lenses
74
The image-intensifier tube’s input phosphor functions to convert
x-rays to light
75
Which of the following equipment is mandatory for performance of a myelogram?
Tilting x-ray table
76
Deposition of vaporized tungsten on the inner surface of the x-ray tube glass window
1. acts as additional filtration
2. results in increased tube output
3. results in anode pitting
1 only
77
Design characteristics of x-ray tube targets that determine heat capacity include the
1. rotation of the anode
2. diameter of the anode
3. size of the focal spot
1, 2 and 3
78
Which of the following terms describes the amount of electric charge flowing per second?
(A) Voltage
(B) Current
(C) Resistance
(D) Capacitance
(B) Current
79
The brightness level of the fluoroscopic image can vary with
1. milliamperage
2. kilovoltage
3. patient thickness
1, 2 and 3
80
A high-speed electron, accelerated toward a tungsten atom, is attracted (and “braked,” that is, slowed down) by the positively charged nucleus and therefore is deflected from its original course with resulting loss of energy.
Bremsstrahlung Radiation
81
Which of the following is the correct formula for determining heat units for a three-phase, 12-pulse x-ray machine?
mA × time × kV × 1.41
82
Component parts of a CT imaging system include a(n)
1. high-frequency generator
2. x-ray tube
3. operator console
1, 2, and 3
83
With what frequency must radiographic equipment be checked for linearity and reproducibility?
Annually
84
Which part of an induction motor is located within the x-ray tube glass envelope?
Rotor
85
A technique chart should be prepared for each AEC x-ray unit and should contain which of the following information for each type of examination?
1. Photocell(s) used
2. Optimum kilovoltage
3. Backup time
1, 2 and 3 only
86
A technique chart should be prepared for each AEC x-ray unit and should contain which of the following information for each type of examination?
1. Photocell(s) used
2. Optimum kilovoltage
3. Backup time
1, 2 and 3
87
Which part of an induction motor is located outside the x-ray tube glass envelope?
Stator
88
Moving the image intensifier closer to the patient during fluoroscopy
1. decreases the SID
2. decreases patient dose
3. improves image quality
1, 2 and 3
89
If a radiograph exposed using an AEC is overexposed because an exposure shorter than the minimum response time was required, the radiographer generally should
decrease the milliamperage
90
Exposures less than the minimum response time of an AEC may be required when
1. using high milliamperage
2. using fast film–screen combinations
3. examining large patients or body parts
1 and 2 only
91
Which of the following is/are associated with magnification fluoroscopy?
1. Higher patient dose than nonmagnification fluoroscopy
2. Higher voltage to the focusing lenses
3. Image intensifier focal point closer to the input phosphor
1, 2, and 3 only
92
Advantages of battery-powered mobile x-ray units include their
1. ability to store a large quantity of energy
2. ability to store energy for extended periods of time 3. lightness and ease of maneuverability
1 and 2 only
93
Which of the following modes of a trifield image intensifier will result in the highest patient dose?
(A) Its 25-in. mode
(B) Its 17-in. mode
(C) Its 12-in. mode
(D) Diameter does not affect patient dose
(C) Its 12-in. mode
94
Off-focus, or extrafocal, radiation is minimized by
restricting the x-ray beam as close to its source as possible
95
Circuit devices that permit electrons to flow in only one direction are
solid-state diodes
96
An AEC device can operate on which of the following principles?
1. A photomultiplier tube charged by a fluorescent screen
2. A parallel-plate ionization chamber charged by x-ray photons
3. Motion of magnetic fields inducing current in a conductor
1 and 2 only
97
Which of the following functions to increase the milliamperage?
(A) Increase in charge of anode
(B) Increase in heat of the filament
(C) Increase in kilovoltage
(D) Increase in focal spot size
(B) Increase in heat of the filament
98
If 92 kV and 15 mAs were used for a particular abdominal exposure with single-phase equipment, what milliampere-seconds value would be required to produce a similar radiograph with three-phase, 12-pulse equipment?
7. 5
| * With three-phase, 12-pulse equipment, the original milliampere-seconds would be cut in half (one-half of 15 mAs = 7.5)
99
Fractional-focus tubes, with a 0.3-mm focal spot or smaller, have special application in
magnification radiography
100
Which of the following devices is used to control voltage by varying resistance?
Rheostat
101
Anode angle will have an effect on the
1. severity of the heel effect
2. focal-spot size
3. heat-load capacity
1, 2 and 3
102
Light-sensitive AEC devices are known as
phototimer
103
Which of the following devices is (are) component(s) of a typical fluoroscopic video display system?
1. Videotape recorder
2. TV camera
3. TV monitor
2 and 3 only
104
A relatively low-energy (low kilovoltage) x-ray photon uses all its energy (true/total absorption) to eject an inner-shell electron, leaving an orbital vacancy.
photoelectric effect
105
Which of the following formulas would the radiographer use to determine the total number of heat units produced with a given exposure using three-phase, six-pulse equipment?
(A) mA × time × kV
(B) mA × time × kV × 3.0
(C) mA × time × kV × 1.35
(D) mA × time × kV × 1.41
(C) mA × time × kV × 1.35
106
With three-phase equipment, the voltage across the x-ray tube
1. drops to zero every 180 degrees
2. is 87% to 96% of the maximum value
3. is at nearly constant potential
2 and 3 only
107
Radiographs from a particular single-phase, full-wave-rectified x-ray unit were overexposed, using known correct exposures. A spinning-top test was performed at 200 mA, 0.05 s, and 70 kV , and 8 dots were visualized on the finished film. Which of the following is indicated?
(A) The 0.05-s time station is inaccurate.
(B) The 200-mA station is inaccurate.
(C) A rectifier is not functioning.
(D) The processor needs servicing.
(A) The 0.05-s time station is inaccurate.
* Because single-phase, full-wave-rectified current has 120 useful impulses per second, a 1-s exposure of the spinning top should demonstrate 120 dots. Therefore, a 0.05-s exposure should demonstrate six dots. Anything more or less than this indicates that the time station needs calibration. If exactly onehalf the expected number of dots appears, one should suspect rectifier failure.
108
Which of the following combinations will offer the greatest heat-loading capability?
(A) 17-degree target angle, 1.2-mm actual focal spot
(B) 10-degree target angle, 1.2-mm actual focal spot
(C) 17-degree target angle, 0.6-mm actual focal spot (D) 10-degree target angle, 0.6-mm actual focal spot
(B) 10-degree target angle, 1.2-mm actual focal spot
*As the target angle decreases, the actual focal spot can be increased while still maintaining a small effective
focal spot.
109
Which of the following would be appropriate IP front material(s)?
1. Tungsten
2. Magnesium
3. Bakelite
2 and 3 only
110
How often are radiographic equipment kV settings required to be evaluated?
Annually
111
The filtering effect of the x-ray tube’s glass envelope and its oil coolant are referred to collectively as
Inherent Filtration
112
Accurate operation of the AEC device depends on
1. the thickness and density of the object
2. positioning of the object with respect to the photocell
3. beam restriction
2 and 3 only
113
The image intensifier’s input phosphor generally is composed of
Cesium Iodide
114
The total number of x-ray photons produced at the target is contingent on the
1. tube current
2. target material
3. square of the kilovoltage
1, 2, and 3
115
A photostimulable phosphor plate is used with
CR
116
X-ray tubes used in CT imaging systems must be capable of
1. high short-exposure rating
2. tolerating millions of heat units
3. high-speed anode rotation
1, 2 and 3
117
The device used to test the accuracy of the x-ray timer is the
Spinning top
118
QA was being performed on a three-phase, full-wave-rectified x-ray unit. A synchronous spinning-top test was performed using 300 mA, 60 ms, and 70 kV , and a 22-degree arc is observed on the test film. Which of the following statements regarding these results is most correct?
(A) The timer is inaccurate.
(B) The milliamperage station is inaccurate.
(C) One rectifier is malfunctioning.
(D) The test results are satisfactory.
(D) The test results are satisfactory.
* Because three-phase, full-wave-rectified current would expose a 360-degree arc each second, a 60-ms (0.06-s) exposure should expose a 21.6-degree arc (360 degrees × 0.06 = 21.6 degrees). Anything more or less indicates timer inaccuracy. If exactly onehalf the expected arc appears, rectifier failure should be suspected.
119
Which of the following statements regarding dual x-ray absorptiometry is (are) true?
1. It is a low-dose procedure.
2. Two x-ray photon energies are used.
3. Photon attenuation by bone is calculated.
1,2 and 3
