Term
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Definition
unit of length equal to 10^-10 (one tenbillionth of a meter)
used for wavelength |
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Term
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Definition
| number of complete oscillations per second of an electromagnetic wave |
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Term
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Definition
| the smallest quantity of any type of electromagnetic radiation |
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Term
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Definition
| a small bundle of photon energy |
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Term
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Definition
distance between two successive similar points on a wave
length of one cycle |
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Term
| electromagnetic radiation |
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Definition
wavelike fluctuations of electric magnetic fields set up in space by oscillating electrons
includes xrays gammarays, etc |
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Term
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Definition
| the degree of blackening of a radiograph resulting from radiation exposure and processing |
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Term
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Definition
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Term
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Definition
| represents high optical density |
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Term
| factors that affect density |
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Definition
MAS
time
distance
kvp
film processing
filtration
patient factor
heel effect
intensifying screens |
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Term
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Definition
also called exit radiation
radiation that exits the anatomic part and exposes the radiographic screens placed in the cassette |
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Term
| composition of xray beams (electromagnetic radiation) |
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Definition
white light
UV light
infrared
microwaves
radiowaves |
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Term
| properties of electromagnetic radiation |
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Definition
highly penetrating, invisible rays
electrically neutral
polyenergetic
liberates minute amounts of heat
travels in straight lines at the speed of light
ionizes gasses indirectly
causes flourescence of certain crystals
cannot be focused by a lens
affects photographic film
produce scattered radiation |
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Term
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Definition
3 x 108 m/s
186,000 miles per second in vacuum |
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Term
| three regions of importance to radiography |
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Definition
visible light
radiofrequency
xradiation
only difference is in frequency and wavelength |
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Term
| velocity= frequency x wavelength |
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Definition
| c= frequency x wavelength |
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Term
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Definition
| an increase in frequency would cause a ____ in wavelength |
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Term
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Definition
| directly proportional to the photon frequency |
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Term
| the constant of proportionality |
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Definition
Plank's constant
symbolized by h
4.15 x 10^-15 ev/s |
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Term
| the relationship between energy and frequency |
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Definition
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Term
| the relationship between energy and frequency |
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Definition
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Term
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Definition
radiation intensity from an xray tube varies inversely with the square of the distance from the target
I1/I2=(D2)^2/ (D1)^2 |
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Term
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Definition
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Term
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Definition
| involves a change in direction |
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Term
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Definition
| the dark areas on a radiograph represent the area where the xray beam hit the film unaltered |
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Term
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Definition
unmodified scatter/thompson effect/ coherent scatter
low every photon is absorbed by an outer shell electron and becomes excited, photon released by atom with same amount of energy as incident photon and goes on a random course |
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Term
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Definition
| moderate to high energy photon interacts with outershell electron, outershell electron is ejected, photon is scattered with less energy and less penetration |
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Term
| almost the entire scatter that we encounter in radiology |
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Definition
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Term
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Definition
a form of noise that degrades the image
caused by compton scattering |
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Term
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Definition
moderate to high energy photon interacts with inner shell electrons
inner shell electron is ejected
most probably when electron binding energy is only slightly less than the energy of the incident photon
varies directly with atomic number of irradiated tissue |
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Term
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Definition
| PE is ___times more likely in bone rather than soft tissue |
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Term
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Definition
high energy photon interacts with nuclear electrostatic field
occurs with photon energy of at least 1.02 MeV |
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Term
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Definition
negative charge
eventually becomes an orbital electron |
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Term
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Definition
| positively charged that eventually combines with a free electron and forms positronium that only exists for 10^-10 seconds |
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Term
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Definition
thee second stage of pair production
positronium disappears, giving rise to two photons, each having an energy of .51 MeV |
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Term
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Definition
high energy photon interacts with the nucleus of an atom
occurs with photon energy above 10 MeV |
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Term
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Definition
only three important xray interactions
compton effect
photoelectric effect
transmission of photon |
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