Equipment Operation & Quality Control Flashcards
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
Thermionic Emission
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
grid-controlled
Typical examples of digital imaging include
- MRI
- CT
- CR
1,2 & 3
Component parts of a CT gantry include
- high-voltage generator
- multidetector array
- x-ray tube
1,2 & 3
Which of the following circuit devices operate(s) on the principle of selfinduction?
- Autotransformer
- Choke coil
- High-voltage transformer
1 & 2 only
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)?
31
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?
200 mA and 110 kV
how many voltage ripple for full wave rectification
100% voltage ripple
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
1 only
The minimum response time of an automatic exposure control (AEC)
is its shortest possible exposure time
Functions to protect the patient from overexposure and the x-ray tube from overload
Back up timer
The electron cloud within the x-ray tube is the product of a process called
Thermionic Emission
Which of the following causes pitting, or many small surface melts, of the anode’s focal track?
Repeated frequent overloading
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.
1,2 & 3
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
AEC
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
1 & 2 only
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) 1.2-mm focal spot, 92 kV , 1.5 mAs
Functions to direct the liberated filament electrons to the focal spot.
Molybdenum Focusing Cup
Congruence of the x-ray beam with the light field is tested using
Radio opaque objects
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
2 & 3 only
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?
55 kV
What is the relationship between kV and HVL?
As kV increases, the HVL increases.
As window level increases
brightness increases
Which of the following is/are components of the secondary, or high voltage, side of the x-ray circuit?
- Rectification system
- Autotransformer
- kV meter
1 only
Patient dose during fluoroscopy is affected by the
- distance between the patient and the input phosphor 2. amount of magnification
- tissue density
1,2 & 3
A backup timer for the AEC serves to
- protect the patient from overexposure
- protect the x-ray tube from excessive heat
- increase or decrease master density
1 & 2 only
Which of the following devices converts electrical energy to mechanical energy? (A) Motor (B) Generator (C) Stator (D) Rotor
motor
The essential function of a phototimer is to
terminate the x-ray exposure once the IR is correctly exposed
A slit camera is used to measure
- focal-spot size
- spatial resolution
- intensifying-screen resolution
1 & 2 only
In which of the following examinations would an IP front with very low absorption properties be especially important?
Mammography
Which of the following will improve the spatial resolution of image intensified images?
- A very thin coating of cesium iodide on the input phosphor
- A smaller-diameter input screen
- Increased total brightness gain
1 and 2 only
The advantages of collimators over aperture diaphragms and flare cones include
- the variety of field sizes available
- more efficient beam restriction
- better cleanup of scattered radiation
1 and 2 only
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.
Characteristics of the metallic element tungsten include
- ready dissipation of heat
- high melting point
- high atomic number
1, 2, and 3
The voltage ripple associated with a three-phase, six-pulse rectified generator is about
13% voltage ripple
The device that receives the remnant beam, converts it into light, and then increases the brightness of that light is the
image intensifier
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
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
Components of digital imaging include
- computer manipulation of the image
- formation of an electronic image on the radiation detector
- formation of an x-ray image directly on the IR
1 and 2 only
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
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
The regular measurement and evaluation of radiographic equipment components and their performance is most accurately termed as
Quality Control
The procedure whose basic operation involves reciprocal motion of the x-ray tube and film is
Tomography
In fluoroscopy, the automatic brightness control is used to adjust the
kilovoltage (kV) and milliamperage (mA)
When the radiographer selects kilovoltage on the control panel, which device is adjusted?
Autotransformer
Star and wye configurations are related to
three-phase transformers
What is the device that directs the light emitted from the image intensifier to various viewing and imaging apparatus?
Beam splitter