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Equipment Operation

Equip and QC 465

QuestionAnswer
What is the source of electrons in the x-ray tube? (Lange Prep, p. 431) Heated cathode filament
A high-speed electron passing near/through an atom is attracted to a positively charged nucleus and deflected from its course with a loss of energy. The energy is given up in the form of an x-ray photon.(Lange Prep, p. 431) Bremsstrahlung
What percentage of the x-ray beam is comprised of bremsstrahlung radiation? (Lange Prep, p. 431) 70%-90%
High speed electron encounters a tungsten atom and ejects a K Shell electron leaving a vacancy in the shell. Vacancy is filled by an L Shell electron and emits a K characteristic x-ray. (Lange Prep, p.431) Characteristic radiation
Energy is equal to the difference in energy between the K and L shell energy level. (Lange Prep, p. 431) Characteristic radiation
What percentage of the x-ray beam is made of up characteristic radiation? (Lange Prep, p. 431) 10%-30%
What components are part of the electromagnetic spectrum? (Lange Prep, p. 431) Visible light, microwaves, radio waves, x-rays, and gamma rays
What is the velocity of the electromagnetic spectrum? (Lange Prep, p. 432) 186,000 miles per second (3x10^8 m/s)
The distance between two consecutive waves crests. (Lange Prep, p. 432) Wavelength
The number of cycles per second, measured in hertz (Hz). (Lange Prep, p. 432) Frequency
What is a short wavelength associated with? (Lange Prep, p. 433) Higher frequency, higher energy, increased ionization potential
Radiation that is hazardous to living tissue; Have energetic potential to break apart neutral atoms, result in production of negative/positive ions. (Lange Prep, p.433) Ionizing radiation
Infinitesimal bundles of energy that deposit energy into matter as they travel through it? (Lange Prep, p. 433) Photons
What has the potential to cause chemical and biological damage when photon energy is deposited into matter? (Lange Prep, p. 433) Ionization
Tissue damage is partially dependent upon what two factors of the x-ray beam? (Lange Prep, p. 433) Quality and quantity
The x-ray beam that emerges from the x-ray tube focal spot? (Lange Prep, p. 433) Primary beam
The x-ray photons that emerge from the imaged part is known as what? (Lange Prep, p. 434) Remnant or exit beam
What principle factor affects beam quantity? (Lange Prep, p.434) mAs
What principle factor affects beam quality? (Lange Prep, p. 434) kVp
Gradual decrease in exposure rate as radiation passes through tissues is called? (Lange Prep, p.434) Attenuation
A relatively low-energy x-ray photon uses all its energy to eject an inner shell electron, leaving an orbital vacancy. An electron from above drops down and fills vacancy and gives up energy in the form of a characteristic x-ray. (Lange Prep, p. 434) Photoelectric effect
The photoelectric effect occurs in areas having a _____ _____ ____ and contributes to ____ _____? (Lange Prep, p. 434) High atomic number; patient dose
A high-energy x-ray photon ejects an outer shell electron. There is little radiation hazard to the patient. Some internal scatter contributes to patient dose. (Lange Prep, p. 434) Compton scatter
Contributes to image fog and poses a radiation hazard to personnel. (Lange Prep, p. 434) Compton scatter
Classical, unmodified, or Rayleigh scatter. The interaction between x-rays and matter occurs with very-low energy x-ray photons, energies rarely used in diagnostic radiology. This is the only interaction where no ionization occurs (Lange Prep, p. 435) Coherent (Classical) Scatter
Attenuation of the x-ray beam is dependent upon? (Lange Prep, p. 435) Thickness or size of body parts, atomic number of the tissues, and pathologic indications
The majority of x-ray equipment is in what kind of position: fixed/stationary or mobile? (Lange Prep, p. 437) Fixed/stationary
What are some examples of dedicated equipment? (Lange Prep, p.437) Mammography equipment, chest units, tomographic equipment, bone densitometry and dental units
What changes mechanical energy to electrical energy? (Lange Prep, p. 437) Generators
What changes electrical energy to mechanical energy? (Lange Prep, p. 437) Motors
What is a positive half-cycle peak? (Lange Prep, p. 437) Crest
What is a negative half-cycle peak? (Lange Prep, p. 437) Trough
What is the height of the wave? (Lange Prep, p. 437) Amplitude
What is Hertz? (Lange Prep, p. 437) Unit of frequency
Electrical current flows in how many directions and what type of current does it utilize? (Lange Prep, p. 437) One direction; direct current
Alternating current is characterized by? (Lange Prep, p. 437) Varying amplitude and periodic reversal of polarity
Alternating current is generated in how many Hz each second? (Lange Prep, p. 438) 60
What is Faraday's observation about the operation of electromagnetic devices? (Lange Prep, p. 439) The magnetic field will induce an electric current in a conductor if there is motion of either the magnetic field or the conductor; this is the fundamental operation of a high-voltage transformer
An alternating current, producing a continuously moving magnetic field, is necessary for what to occur? (Lange Prep, p. 439) Mutual induction
A conductive wire shaped like a coil is called? (Lange Prep, p. 439) Helix
What are used to increase the incoming voltage to the more useful kilovoltage required for x-ray production? (Lange Prep, p. 440) Transformers
What kind of transformer increase the voltage and decreases amperage? (Lange Prep, p. 440-441) Step-up transformer or high voltage transformer
The degree to which transformers increase the voltage is determined by? (Lange Prep, p. 440) Turns ratio
As ____ increases, _____ decreases. (Lange Prep, p. 440) Voltage; current
What is the equation of the transformer law? (Lange Prep, p. 440) V^s / V^p = N^s /N^p N^s / N^p = I^p / I^s
The relationship between the turns ratio and the voltage is? (Lange Prep, p. 440) Direct
The relationship between the turns ratio and the current is? (Lange Prep, p. 440) Indirect
What kind of transformer decreases voltage and increases amperage? (Lange Prep, p. 441) Step down transformer
An autotransformer operates on the concept of? (Lange Prep, p. 441) Self-induction
How many coils does an autotransformer have? (Lange Prep, p. 441) One
A single phase full-wave has a ripple percentage of? (Lange Prep, p. 442) 100%
A three phase, six pulse has a ripple percent of? (Lange Prep, p. 442) 13%
A three phase, twelve pulse has a ripple percent of? (Lange Prep, p. 442) 4%
A high frequency generator has a ripple percent of? (Lange Prep, p. 442) <1%
The x-ray tube is made up of what parts? (Lange Prep, p. 444) Anode, cathode, glass envelope
The positive side of the x-ray tube is? (Lange Prep, p. 444) Anode
The negative side of the x-ray tube is? (Lange Prep, p. 444) Cathode
The cathode consists of what parts? (Lange Prep, p. 444) One or more filaments, their supporting wires, and a focusing cup
The anode is made up of what parts? (Lange Prep, p. 445) Molybdenum disk with beveled edge, Tungsten alloy focal track, Copper stem
The boiling off of outer shell tungsten electrons is? (Lange Prep, p. 445) Thermionic emission
The x-ray tube has how many filaments? (Lange Prep, p. 445) Two: large and small
The anode rotates through the use of an? (Lange Prep, p. 445) Induction motor
The induction motor is made up of? (Lange Prep, p. 445) Stator and rotor
What percentage of kinetic energy of the electron stream is converted to x-rays? (Lange Prep, p. 447) 0.2%
The width of the finite area on the tungsten target? (Lange Prep, p. 447) Actual focal spot
The foreshortened size of the focus as it is projected down toward the image receptor, as it would be seen looking up into the x-ray tube. Affected by the degree of focal track bevel or anode angle (Lange Prep, p. 447) Effective/projected or apparent focal spot
The anode angle is how many degrees? (Lange Prep, p. 447) 5-20 degrees
The size of the effective focal spot is dependent upon? (Lange Prep, p. 447) The length of the image receptor; largest at cathode, smallest at anode side
The effective focal spot is always small than the actual focal spot is known as? (Lange Prep, p. 448) Line focus principle
The anode heel effect is used when imaging? (Lange Prep, p. 448) Uneven thickness
The thicker port of the body would be placed near which side of the x-ray tube when using the anode heel effect? (Lange Prep, p. 448) Cathode end
The equation for heat units (HU) is? (Lange Prep, p. 448) HU = mA x s x kV x (single phase)
X-ray tube safety limits are expressed in what two charts? (Lange Prep, p. 449) Tube rate charts and anode cooling curve
What are some causes of x-ray tube failure? (Lange Prep, p. 449) Vaporized tungsten, pitted anode, cracked anode, and gassy tube
Vaporized tungsten is the result of? (Lange Prep, p. 449) Thermionic emission
Pitted anode results from? (Lange Prep, p. 449) Exposures made to the tube exceeding the tube rating chart
Cracked anode results from? (Lange Prep, p. 449) A single large exposure made to a cold anode
Gassy tube results from? (Lange Prep, p. 450) Air molecules colliding with and decelerating the high speed electrons in the vacuum tube, reducing the efficiency of the x-ray production
The primary circuit/low-voltage contains? (Lange Prep, p. 451) The devices on the control console
The filament circuit varies? (Lange Prep, p. 451) The current sent to the filament to provide the required mA value
The high-voltage/secondary circuit includes? (Lange Prep, p. 451) The high voltage transformer, rectification system, and x-ray tube
These are location on the wall in or near the x-ray room and must be closed to energize the equipment. (Lange Prep, p. 451) Main switch and circuit breaker
Variable transformer that operates on AC and enable the radiographer to select kilovoltage. (Lange Prep, p. 451) Autotransformer
Used by the radiographer to choose the kilovoltage, often as kV major and kV minor. (Lange Prep, p. 451) kV selector
Functions to automatically adjust for any fluctuations in incoming voltage supply. (Lange Prep, p. 452) Line voltage compensator
Functions to regulate the length of x-ray exposures. (Lange Prep, p. 452) Timers
Types of timers include? (Lange Prep, p. 452) Mechanical, synchronous, impulse, electronic, mAs, AEC
Type of timer used today is? (Lange Prep, p. 452) Electronic timer
What type of test is used for evaluating timer accuracy? (Lange Prep, p. 454) Spinning top test
The primary/low-voltage circuit components include? (Lange Prep, p. 455) Main switch,/circuit breaker, autotransformer, kV selector switch, Line voltage compensator, timer, primary coil of KV transformer, exposure switch
When testing a three phase, full-rectified equipment, what type of test is used to measure accuracy? (Lange Prep, p. 455) Synchronous (motorized) spinning top
Low voltage entering the primary coil is stepped up to high kilovoltage in the secondary coil by means of mutual induction. (Lange Prep, p. 455) Primary coil of the high voltage transformer
The remote control switch that functions to start the x-ray exposure. (Lange Prep, p. 455) Exposure switch
Supplies low voltage current to the filament of the x-ray tube. Incoming voltage is greater than required, a step-down transformer is placed here. A rheostate/resistor is placed to adjust amperage and corresponds to mA selector. (Lange Prep, p. 455) Filament circuit
Carries the required high voltage for x-ray production. (Lange Prep, p. 455) Secondary coil of high-voltage transformer
Located at the midpoint of the secondary transformer coil. It's grounded and can be safely placed in operator console. (Lange Prep, p. 455) mA meter
System of diodes located between the secondary coil of the high-voltage transformer and x-ray tube. Rectifiers
Final device in secondary circuit. Thermionic electron cloud is driven to the anode target. Electron interaction with tungsten atoms of the target, results in energy conversion to heat and x-rays. (Lange Prep, p. 455) X-ray tube
Consists of hardware (physical component) and software (set of instructions or program to operate it) (Lange Prep, p. 456) Computer system
Computer terminology refers to an individual 1 or 0 and is a single bit of information. (Lange Prep, p. 457) Binary numbers
Two dimensional, picture element, measured in XY direction, image storage. (Lange Prep, p. 457) PIxel
Third dimension, depth, volume element, measured in Z direction. (Lange Prep, p. 457) Voxel
Number of pixels in XY direction. (Lange Prep, p. 457) Matrix
How much of the part/patient is included in the matrix. (Lange Prep, p. 457) Field of View (FOV)
Number of bits required to describe the gray level that each pixel can take on. (Lange Prep, p. 458) Bit depth
The larger the matrix, the better the ____ _______. (Lange Prep, p. 458) Image resolution
Measured in line pairs per millimeter (Lange Prep, p. 458) Spatial resolution
Ability to transmit images over a distance. (Lange Prep, p. 458) Teleradiology
Film-less radiography. A photostimulable storage phosphor within the IP is used as the IR. (Lange Prep, p. 459) Computed radiography
Storage plate receives x-ray photons, x-ray energy interacts with the barium fluorohalide crystals, which emits visible light. Stored energy represents what? (Lange Prep, p. 459) Latent image
Stored image is placed in CR reader, PSP screen is removed and the latent image becomes a? (Lange Prep, p. 460) Visible image
In PSP imaging, the latent image is read by a ______ in the CR reader. (Lange Prep, p. 460) High intensity helium neon laser or a solid state laser
An artifact associated with digital imaging and grids is known as? (Lange Prep, p. 461) Aliasing or the Moire Effect
PSP is erased by exposing the PSP screen to a? (Lange Prep, p. 462) Laser
Process of changing the contrast and density setting on the monitor. (Lange Prep, p. 463) Windowing
Controls the number of shades of gray in the image (Lange Prep, p. 463) Window width
Density/brightness of an image is? (Lange Prep, p. 463) Window level
Range of grays of a particular digital system (Lange Prep, p. 463) Contrast resolution
Term for anything that interferes with visualization of the image. (Lange Prep, p. 463) Noise
Graininess in an image is known as? (Lange Prep, p. 463) Quantum mottle
Digital flat, plate-like, panel. (Lange Prep, p. 465) Flat panel detector
Two types of flat panel detectors are? (Lange Prep, p. 465) Indirect and direct
A type of indirect flat panel detector is? (Lange Prep, p. 465) TFT system
Indirect conversion detectors are? (Lange Prep, p. 466) Converted to light scintillations and light is converted to electric signals
Direct conversion detectors are? (Lange Prep, p. 466) Directly converted to electric signals
Who created the first CT unit? (Lange Prep, p. 467) Sir Godfrey Newbold Hounsfield
The first CT scanner was available in? (Lange Prep, p. 468) 1971
Axial images demonstrate which direction? (Lange Prep, p. 468) Inferior/superior
Coronal images are demonstrated in what direction? (Lange Prep, p. 468) Anterior/posterior
Sagittal images are demonstrated in what direction? (Lange Prep, p. 468) Medial/lateral
What allows for continuous rotation around the CT gantry? (Lange Prep, p. 472) Slip ring technology
What is the term given to the 6th generation CT scanner? (Lange Prep, p. 472) Helical or spiral
What does it mean for a fluoroscopic table to be 90/30? (Lange Prep, p. 475) It goes 90 degrees upright and angle Trendelenburg up to 30 degrees.
What are some advantages of flat panel fluoroscopy? (Lange Prep, p. 476) Pulsed x-ray beam, decreased patient dose, increased sensitivity to x-rays, increased temporal resolution, decreased motion unsharpness, improved contrast resolution
What is the maximum tabletop exposure rate for fluoroscopy? (Lange Prep, p. 478) 10 mR/minute
What type of switch is used in fluoroscopy? (Lange Prep, p. 478) Deadman switch
What are some safety measures taken to reduce exposure to the technologist? (Lange Prep, p. 478) Bucky slot cover, automatic collimation, protective curtain
What type of time is used in fluoroscopy? (Lange Prep, p. 478) 5 minute timer
What is the minimum distance for a fluoroscopic table? (Lange Prep, p. 478) 12 inches
The image intensifier is made of? (Lange Prep, p. 479) Cesium iodide
The ratio of light photons as the output phosphor to the number at the input phosphor. (Lange Prep, p. 480) Flux gain
The amount of fluorescent light emitted from it per unit area is significantly greater than the quantity of light emitted from the input screen. (Lange Prep, p. 480) Minification gain
The equation for minification gain is? (Lange Prep, p. 480) minification gain = (input screen diameter / output screen diameter)^2
A common type of image distortion is called? (Lange Prep, p. 481) Pincushion distortion
_____ is caused by the curvature of the input screen and diminished electron focusing precision at the image periphery. (Lange Prep, p. 481) Pincushion distortion
Entrance skin exposure increases as _____ decreases. (Lange Prep, p. 481) FOV
What are the most common types of analog television cameras? (Lange Prep, p. 482) Vidicon and Plumbicon
Digital images can be stored on? (Lange Prep, p. 483) Magnetic tape, disks, digital videotape, and optical disks and tape
The common spot film sizes are? (Lange Prep, p. 483) 70 mm, 90mm, and 105 mm
CCD converts visible light to what? (Lange Prep, p. 484) Electrical charge
The time it takes the tube reach the required exposure factors? (Lange Prep, p. 484) Interrogation time
The time it takes for the tube to shut off is known as? (Lange Prep, p. 484) Extinction time
The extinction time required is? (Lange Prep, p. 484) 1 millisecond
What are some advantages of DF photospots? (Lange Prep, p. 484) No chemical processing needed, decreased patient dose, postprocessing capability, road-mapping capability
Organized and methodical evaluation of imaging components from the x-ray tube to the automatic film processor, with the purpose of decrease repeat exposures, thus decreasing patient exposure and increase cost effectiveness. (Lange Prep, p. 493) Radiographic quality control
Ranges from daily processor checks to quarterly, semiannual, and annual equipment performance testing. (Lange Prep, p. 493) Frequency of testing
Who is included in the quality control program? (Lange Prep, p. 493) Radiographer, QC technologist, service engineer, and medical physicist
The selected kV and the actual kV should not vary by more than how much? (Lange Prep, p. 494) + or - 4
What tests can be used to check mA? (Lange Prep, p. 495) Aluminum step-wedge
How is linearity of mA checked? (Lange Prep, p. 495) Digital dosimeter
Timer accuracy is checked by using a? (Lange Prep, p. 495) Spinning top test
The exposure time should be accurate to within what percent of the actual exposure time? (Lange Prep, p. 495) 5%
The relationship between the collimator light field and the actual x-ray field. (Lange Prep, p. 496) Congruence
The collimator light field and actual x-ray field should be accurate to within what percent? (Lange Prep, p. 496) 2% of SID
In reproducibility, the digital radiation meter should register radiation output that does not vary more than what percent? (Lange Prep, p. 496) 5%
The thickness of any absorber that will reduce x-ray beam intensity to one-half its original value is? (Lange Prep, p. 496) Half value layer
Focal spot size can be measured with what? (Lange Prep, p. 497) Pinhole camera, slit camera or star-pattern type resolution device
What is used for intensifying screen testing? (Lange Prep, p. 497) Wire mesh
What is the skin entrance dose limit for interventional procedures? (Lange Prep, p. 498) 100 rad
What types of shielding are available for fluoroscopy procedures? (Lange Prep, p. 499) Lead aprons, gloves and thyroid shields
What test is performed to evaluate tube performance? (Lange Prep, p. 499) Sharpness test
Approximately how many exposures can a PSP screen be exposed to during it's lifetime? (Lange Prep, p. 500) 10,000
Created by: KelliAnn2292