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123 Cards in this Set
- Front
- Back
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As the primary x-ray beam passes through anatomic tissue, it will lose some of its energy. This reduction in the energy is known as ___________.
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Attenuation
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Three distinct processes occur during beam attenuation:_____________, _____________ and _____________.
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Absorption, scattering and photon transmission
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The ability to remove electrons is known as _____________.
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Ionization
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The ejected electron during absorption is called a _______________.
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Photoelectron
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As the energy of the primary x-ray beam is deposited within the atoms of the tissue, some photons will be completely ____________.
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Absorbed
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The process of image formation is a result of ____________ ___________ of the x-ray beam as it interacts with the anatomic tissue.
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Differential Absorption
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If all photons passed through a patient, the image would be _________.
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Black
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If no photons passed through a patient, the image would be __________.
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White
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The x-ray photon responsible for absorption is ___________.
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Photoelectric
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When a photons interacts with an outer shell electron, knocks it out and changes direction (scatters), this is called the ___________ ___________.
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Compton Effect
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Some incoming photons are not absorbed, but instead lose energy during interactions with the atoms comprising the tissue. This process is called ___________.
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Scattering
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Compton Interactions occur within all diagnostic radiation.
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True
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At a fairly low KvP, you have more _________ __________ than you will Compton.
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Photoelectric interactions
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At a higher KvP, you will have more ___________ interactions
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Compton
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When the incoming photon passes through the anatomic part without any interaction with the atomic structure, this is called ______________.
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Transmission
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____________ radiation creates unwanted density called fog.
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Scatter
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When the attenuated x-ray beam leaves the patient, the remaining x-ray beam is referred to as ___________ ____________.
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Remnant radiation
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Exit, or remnant, radiation is composed of both ___________ and ____________ radiation.
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transmitted and scattered
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The exit radiation that interacts with an image receptor creates the latent image.
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True
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__________ allows imaging of the movement of internal structures. This imaging involves constant radiation exposure.
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Fluoroscopy
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What percent of the primary x-ray beam interacting with the anatomic part actually reaches the image receptor?
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5%
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Dynamic imaging of internal anatomic structures can be visualized with the use of an ___________ ___________.
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Image Intensifier
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Digital imaging is converted to ________ _________.
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Digital Data
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What converts electrons to visible light?
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Input Phosphor
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Two types of digital radiographic systems are in use today. They are _______ and ________.
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CR and DR
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_______is cassette type radiography,
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CR (Computed Radiography)
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________is cassetteless type radiography.
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DR (Direct Digital Radiography)
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Once the fluoroscopic image is digitized, a computer can manipulate the image in a variety of ways.
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True
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________ _________ creates a brighter image for viewing by the combination of flux gain and minification gain.
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Image intensification
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What image intensifier component converts the visible light intensities from the input phosphor to electrons?
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photocathode
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_________ __________ is the amount of overall blackness produced on the image after processing.
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Radiographic density
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A primary responsibility of the radiographer is to __________ radiographic images to determine whether sufficient information exists for diagnosis.
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Evaluate
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A radiograph that needs no improvement is defined as _________.
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Optimal
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Techs will evaluate the image for which two properties?
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Photographic and Geometric
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Factors that affect the visibility of a radiographic image are known as ____________
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Photographic
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Factors that directly affect density are identified as ________ ________.
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Controlling Factors
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Factors that indirectly affect density are identified as _________ __________.
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Influencing Factors
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The two Controlling Factors that directly affect density are __________ and ___________.
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mA and Exposure Time
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Milliamperage and exposure time control the __________ of radiation reaching the Image Receptor.
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Quantity
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The number of electrons boiled off the filament is ___________
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mA
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If the image is too light or too dark you will adjust the __________.
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mAs
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If you increase the quantity of x-rays, you (increase/decrease) radiographic density.
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increase
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Amount of radiation produced (mAs) is (directly/indirectly) proportional to the amount of radiographic density.
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Directly
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mAs can be doubled by doubling the mA or doubling the _______ ________.
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Exposure Time
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mA and Exposure Time have an _________ relationship when maintaining mAs..
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Inverse
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100 mA @ 0.10 s = 10mAs. To increase the mAs to 20 you could use
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200 mA @ 0.10s
or 100 mA @ 0.20s |
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The minimum change needed to correct for a density error is determined by multiplying or dividing the mAs by ________.
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2
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Making a visible change in density requires that the minimum amount of change in mAs be approximately ____%.
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30
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Adjusting kVp has a(n) (controlling/influencing) factor on radiographic density.
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Influencing
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kVp affects radiographic density because it alters the amount and penetrating ability of the x-ray beam.
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True
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Increasing the kVp (increase/decreases) the quantity of radiation reaching the IR and therefore (increases/decreases) radiographic density.
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Increase
Increases |
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Maintaining mAs. 100 mA @ 100 ms = 10 mAs. To maintain the mAs, you could use...
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200 mA @ 50 ms = 10 mAs
or 50 mA @ 200 ms = 10 mAs |
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if al photons went through the patient - what color would the image be?
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black
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if no xrays made it to the IR, what color would the image be?
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clear or white
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What level of density would a bone be? low, medium, or high?
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low - shows up white
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If an image shows up gray, how many photons are reaching the IR?
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some
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What level of density would the lung be? Low, medium or high?
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High - shows up black
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Potoelectric effect is __________ asorption.
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total asporption
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Scatter radiation has: lower or higher energy?
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lower
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What does scatter create on an image?
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fog
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There are 2 types of scatter interaction - what are they?
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coherent & compton effects
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What is more prevelent? Compton effet or Coherent?
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Compton
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When does the Compton effect occur?
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within all diagnostic ratiation
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The higher the kVp, the higher or lower the absorption?
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Lower (less absorption)
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The lower the kVp, the higher or lower the absorption
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more absorption
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Incomming phoon passes through patient without any interactions is called what? ___________ __________________
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transmission process
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the lower the kVp the more/ less photons pass through the patient therefore they are/are not absorbed
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less photons - are absorbed
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The higher the kVp the more/ less photons pass through the patient therefore they are/ are not absorbed
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more photons - are NOT absorbed
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What are xrays in real time?
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fluro
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what does the image intensifier do?
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intensifies the image :) brighness gain makes the image brighter.
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What is it called when information on an IR is converted to numerical data?
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Digital imaging
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What properties are a visably recorded detail?
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photographic properties
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what is the overall blackness produced on image after process?
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Density
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There are 2 types of factors that affect radiographic density - what are they?
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controlling & influencing factors
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What are the 2 controlling (primary) factors of density?
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miliamprage (mA)
exposure time (s) |
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mAs affects the quality/ quantity of xray photons?
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quantity
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the more mAs the lighter/ darker your image?
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darker
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if an image is too light or too dark, what would you change?
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the mAs
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if you increase the quantity of xrays the rad density would increase/ decrease and the mAs would increase/ decrease
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both would increase
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the amount of mAs (radiation) produces is directly/ indirectly proportional to radiographic density?
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directly
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in order to really see a difference in an image you'll have to ______ or ______ your mAs.
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double or 1/2
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in order to retake an image the change would have to be by at least ____% in order to see the changes.
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30#
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What factors INDIRECTLY influence radiographic density.
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influencing (secondary) factors
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kVp in/directly affects radiographic densityby congtrolling penetrating ability.
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indirectly
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what rule is used to maintain or adjust rad density.
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15% rule
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what effect does the 15% rule have to the density.
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the same as doubling the mAs (examples of this being done for pregnant lady, portable equiptment)
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to increase density by 15% rule (double darkness) starting w/ 80 kVp, what would the new KVP be?
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92 kVp
80 kVp x 15%= 12 80 kVp + 12 = 92 kVp |
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to decrease density using 15% rule (1/2 the light)
starting w/ 80 kVp, what would the new kVp be? |
68 kVp
80 kVp x 15% = 12 80 kVp - 12 = 68 kVp |
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to maintain density using 15% rule you would?
note: using 80 kVp |
increase =
80kVp + 15% = 92 kVp; mAs/ 2 decrease = 80 kVp - 15% = 68 kVp, mAs x 2 |
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as the SID increases the density in/decreases?
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decreases
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as the SID decreases the density in/decreases?
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increases
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what law states that the intesity of of xray beam is inversly proportional to the square of the distance of the source
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inverse square law
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what is the inverse square law?
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(write in)
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As the SID is increased the intensity is: spread out or more concentrated
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spread out
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As the SID is decreased the intensity is: spread out or more conentrated
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more concentrated
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the maintenance density formula is used when? and what is the formula?
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patient in traction or trauma - when don't have distance needed
(write in formula) |
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a large OID will reduce/ increase the rad density?
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reduce
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Grids absorb xrays therefore you'll have to increase/ decrease the ____
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increase the mAs
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Know the grid conversion chart (p. 74)
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Grid Ratio GCF
no grid 1 5:1 2 6:1 3 8:1 4 12:1 5 16:1 6 |
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the higher the grid ration the more/ less mAs is needed?
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more
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Grid conversion factor
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write in
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the more sensitie the film screen system the more/ less sensitive the greater the speed.
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more
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Film screen grid formula
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write in
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Collumation: the smaller the field size s increasing/ decreasing collumation; therefore increasing/ decreasing the density
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increasing collumation, decreasig the density
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when considering anatomial body parts - for every difference in part thickness of ____ cm, you adjust the mAs by a factor of _____
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4 cm, factor of 2
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When using the anode heel effect the thick/ thin part goes under the cathode because the beam is more/ less intense than the anode side.
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thick portion, more intense
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Decreasing collimation (wider field sizes) (increases/decreases) density.
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Increases
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What is a device that is placed between the patient and IR to absorb scatter radiation exiting the patient?
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Radiographic Grid
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The (slower/faster) the film speed the more detail on the image.
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slower
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What is the degree of difference between adjacent densities?
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Contrast
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_________ ___________ is a result of the absorption characteristics of the anatomic tissue radigraphed and the level of kV used.
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Subject Contrast
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What is considered the controlling factor for radiographic contrast?
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kVp
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As the thickness of a given type of anatomic tissue increases, the amount of scatter radiation (increases/decreases) and contrast (increases/decreases).
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increases
decreases |
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The higher the atomic number of an anatomic tissue the (more/less) absorption occurs.
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more
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The lungs have a higher atomic # than bone.
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False
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The less scatter that reaches the IR, the (higher/lower) the contrast.
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higher
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Increased collimation (increases/decreases) radiographic contrast.
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increases
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Increased collimation (increases/decreases) radiographic density.
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decreases
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The greater the OID, the less scatter hits the IR, the (greater/lesser) the contrast
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greater
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Whenever the amount of scatter radiation reaching the IR is reduced, the radiographic contrast is (increased/decreased)
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increased
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Increased energy = increased scatter = (increased/decreased) contrast.
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decreased
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What is a negative contrast media?
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Air
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A substance that can be instilled into the body by injection or ingestion.
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Contrast Media
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