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106 Cards in this Set
- Front
- Back
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Examples of dedicated x-ray equipment include __________. |
Mobile equipment Dedicated chest units |
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What part of the X-ray equipment is used for the selection of exam parameters? |
The operating console |
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In a general-purpose x-ray room, the fluoroscopy tube will usually be located ___________. |
Under the x-ray table |
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What characteristics would the X-ray table require if it were to be used for fluoroscopy? |
It would have to be a tilting table; 90° to the feet, 30° to the head |
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What does #1 in this illustration represent? |
The tungsten filament |
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What material is #5 usually made? |
Copper |
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What does #2 represent? |
The focusing cup |
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At what number is the source of electrons? |
#1 |
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For what three reasons is tungsten the target material of choice? |
High atomic number High melting point High thermal conductivity |
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What device functions to rotate the anode? |
The induction motor |
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How do the actual and effective focal spot differ in size? |
The effective focal spot is smaller than the actual focal spot |
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To what does the line focus principle refer? |
The relationship between the actual and effective focal spots |
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The stator and the rotor are the two parts of which device? |
The induction motor |
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Of what material is the anode stem usually made, and what is its purpose? |
Copper; to conduct heat away from the face of the anode |
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List two reasons why x-ray tubes are surrounded with oil. |
To conduct heat away from the anode Insulation |
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What is the heat unit (HU) formula? |
HU = mA • time • kV |
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What is used to determine the maximum safe exposure for a particular x-ray tube? |
Tube rating chart |
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The x-ray tube may accurately be described as a/an __________. |
Diode |
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List the three fundamental parts of the typical diagnostic x-ray tube. |
Anode Cathode Vacuum glass envelope |
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A double-focus x-ray tube is one that has __________. |
Two focal spots with two filaments |
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The x-ray tube filament is made of what |
Tungsten |
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The body of the anode is made of __________ and its focal track is made of __________. |
Molybdenum or graphite disk Tungsten and rhenium alloy |
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What is most damaging to the x-ray tube? |
Heat |
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The type of AEC located behind the IR is the __________. |
Photomultiplier/phototimer type |
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The type of AEC most often used, which is placed between the patient and the IR, is the __________. |
Ionization chamber type |
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When using AEC, the electric (manual) timer acts as the __________ and should be set to 1.5 times the expected exposure time. This is done to protect the __________ and the __________. |
Back up timer Patient X-ray tube |
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What permits density/exposure adjustments when using AEC? |
Plus (+) density and minus (-) density/exposure controls |
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What type of AEC uses a fluorescent screen to terminate the exposure? |
Photomultiplier/phototimer type |
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In order to produce predictable and accurate results, AECs require precise ___________ and __________. |
Positioning Centering of CR |
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Why are the uppermost collimator shutters placed as close as possible to the x-ray tube port window? |
To reduce the amount of off-focus/stem radiation exiting the x-ray tube |
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What are the two important functions of beam restriction? |
Reduce patient dose Improve image contrast |
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X-ray photons produced when projectile electrons interact with structures other than the focal spot are termed __________. |
Off-focus or stem radiation |
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What are the two devices that function to reduce the amount of scattered radiation reaching the IR? |
Beam restrictors Grids |
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In what two ways can we reduce the production of scattered radiation? |
Use of beam restriction Appropriate level kV |
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What is the name of the electrical device that operates on the principle of mutual induction and functions to change the magnitude of voltage and current? |
Transformer |
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What type of current is required to operate a transformer? |
Alternating current |
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A step-up transformer has a __________ number of turns in the secondary coil than in the primary coil. |
Greater |
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How does a step-up transformer change voltage and amperage? |
Voltage is increased and amperage is decreased proportionally |
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Step-up and step-down transformers operate on what principle? |
Mutual induction |
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What type of transformer has a turns ratio greater than 1? |
Step-up transformer |
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In a step-up transformer, the secondary current is __________ the primary current. |
Less than |
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What type of transformer has one coil and varies both the current and voltage? |
Autotransformer |
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What type of transformer is the high-voltage transformer? |
Step-up transformer |
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What type of transformer is the filament transformer? |
A step-down transformer |
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The high-voltage side of the typical x-ray circuit contains which three principal parts? |
High-voltage transformer Filament transformer Rectifiers |
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The process of converting alternating current to unidirectional pulsating current/direct current is called __________. |
Rectification |
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Electronic devices found in the x-ray circuit that allow current to flow in only one direction are called __________. |
Rectifiers |
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On what type of current does the x-ray tube most efficiently operate? |
Unidirectional/dc |
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Most solid-state diode rectifiers are made of what semiconductor material? |
Silicon |
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X-ray equipment operated by three-phase 12-pulse power produces what percentage voltage ripple? |
4% |
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What type of electrical power utilizes 3 simultaneous voltage waveforms out of step with each other by 120°? |
Three-phase power |
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How does the voltage applied to the x-ray tube differ between single-phase and three-phase power? |
Three-phase power: applied voltage never drops to zero |
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What type of voltage generators uses inverter circuits to convert dc into a series of square pulses? |
High-frequency generators |
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X-ray equipment operated by single-phase power produces what percentage voltage ripple? |
100% |
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How much kV reduction can be expected using three-phase equipment compared to single-phase equipment? |
10 kV |
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How are x-ray quantity and quality affected when changing from half-wave to full-wave rectification? |
X-ray quantity doubles Quality remains unchanged |
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What is the name of the electronic vacuum tube that functions to amplify the fluoroscopic image, therefore reducing patient dose? |
Image intensifier |
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Fluoroscopic x-ray photons exiting the patient first encounter which part of the image intensifier? |
Import phosphor |
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What component of the image intensifier emits electrons? |
Photocathode |
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How does the image on the image intensifier's output phosphor compare with the image on its input phosphor? |
The image on the output phosphor is minified, brighter, and inverted |
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What material is the image intensifier's input phosphor usually made? |
Cesium iodide |
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What is emitted by the photocathode when it is struck by light photons emitted by the input phosphor? |
Electrons |
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What component of the image intensifier assists and directing electrons toward the output phosphor? |
Electrostatic focusing lenses |
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Which number in the illustration identifies the photocathode? |
4 |
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Which number in the illustration identifies the output phosphor? |
8 |
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Which number illustrates the use of the default mode? |
1 |
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This equation is used to determine __________. |
Minification gain |
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This equation is known as __________. |
The Transformer Law |
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Minificaton gain • flux gain = |
Total brightness gain |
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How is fluoroscopic magnification mode related to spatial resolution, contrast resolution, and patient dose? |
Improved spatial resolution Improved contrast resolution Higher patient dose |
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The reduction in brightness around the periphery of the fluoroscopic image is termed __________. |
Vignetting |
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What two kinds of devices may be used to convert the fluoroscopic output phosphor image into an electronic signal? |
TV camera Charge coupled device (CCD) |
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The use of pulsed fluoroscopy can function to __________ patient dose. |
Decrease |
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A TV camera and a CCD each function to convert the output phosphor image into __________. |
An electronic signal |
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Which device, a TV camera or a CCD, has greater sensitivity to light and provides a higher SNR and improved contrast resolution? |
CCD |
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The fluoroscopic x-ray tube operates in the radiographic mode during what kind of fluoroscopy? |
Digital |
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A stored fluoroscopic image, from the immediately previous fluoroscopic exposure, is a dose-reducing feature termed __________. |
Last image hold |
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What type of exposures are made during digital fluoroscopy (DF)? |
Pulse exposures |
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In DF, what is the term used to describe the time required for the x-ray tube to be switched on and reach the selected factors? |
Interrogation time |
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In DF, what is the term used to describe the time required for the x-ray tube to terminate its exposure? |
Extinction time |
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During DF, the under-table x-ray tube operates in the __________ mode. |
Radiographic |
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What device is connected to the output phosphor of the DF image intensifier tube? |
The CCD |
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How is the use of CCDs related to spatial resolution, SNR, DQE, and patient dose? |
High spatial resolution High SNR High DQE Lower patient dose |
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How do flat-panel digital fluoroscopy detectors compare to CCDs with respect to contrast resolution, image distortion, and DQE? |
FPDF detectors provide better contrast resolution, uniformly distortion-free images, and high DQE |
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When comparing CR and DR, which CR step is omitted in DR? |
The scintillation step |
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What shape is the image display format in flat-panel digital fluoroscopy compared to traditional image-intensified fluoroscopy? |
FPDF is rectangular rather than circular |
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In which system, FPDF or image-intensified fluoroscopy, are pixels less likely to be distorted? |
FPDF |
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What do FPDF units use to convert x-rays directly into electrical charges? |
An amorphous selenium photoconductor |
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What x-rays scintillator may be used for indirect flat panel radiographic or fluoroscopic imaging? |
Cesium iodide or gadolinium oxysulfide |
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What is the digital imaging postprocessing function that can re-register an image to correct for patient motion during serial image acquisition? |
Pixel shift |
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What is the digital imaging postprocessing function that enables addition of text to an image? |
Annotation |
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The process of transmitting images remotely, and viewing remote images is termed __________. |
Teleradiology |
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What is the fluoroscopic feature that changes kV and/or mA according to part thickness? |
Automatic brightness control |
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Certain materials emit light when they are exposed to another type of light. This characteristic is called __________. |
Photostimulable luminescence (PSL) |
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The storage screens typically used in CR contain what type of phosphor material? |
Europium-activated barium fluorohalide |
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Arrange the following six layers of a PSP screen in correct order from front to back: Reflective layer Phosphor layer Base Protective coat Lead Antistatic layer |
Protective coat Phosphor layer Reflective layer Base Antistatic layer Lead |
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What is the function of the image plate? |
To house and protect the PSP |
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Arrange the following CR steps in order from the first to last: Read Stimulate Erase Expose |
Expose Stimulate Read Erase |
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What kind of light is used to stimulate the PSP? |
Monochromatic helium neon gas laser or a solid state laser beam |
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Why must the image plates be erased after use? |
To remove any residual image |
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What is used to erase the PSP? |
Intense white light |
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Why should PSPs be processed and read soon after exposure? |
Signal loss (image fading) becomes apparent after approximately 8 hours |
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Name the two most common types of mobile/portable x-ray equipment. |
Battery operated and capacitor discharge |
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List three common uses of mobile/portable x-ray equipment. |
Trauma radiography Bedside radiography Surgical radiography |
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What is the term used to describe radiation dose and volume of irritated tissue? |
Dose area product (DAP) |
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What type of mobile x-ray unit uses a grid-controlled x-ray tube? |
Condenser/capacitor discharge mobile unit |
