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69 Cards in this Set
- Front
- Back
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an increase in kvp will increase the speed of these in the current.
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electrons
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measured in units called Milliamperes (mA)
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tube current
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this prime factor when increased will decrease contrast
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kVp
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only factor for contrast
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kvp
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this prime factor when increased will decrease the quantity of photons reaching the IR
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SID
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this material has a high atomic #, a high melting pt. & high thermal conductivity
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tungsten
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the target is made of what
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tungsten
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this provides thermal storage for the anode
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graphite
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the electric motor that is a series of electromagnetic that is outside the glass envelope
in glass |
stator
rotor |
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a radio graph w/ few densities but great difference among them is said to have
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high contrast/short scale
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instrument used to measure density on a radiograph
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densitometer
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science of measuring densities using a densitometer
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sensitometry
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based on this principle the smaller the angle the smaller the effective focal spot
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line focus principle
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reduction in the energy of the primary x-ray beam as it passes through anatomic tissue
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attenuation
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a device used to reduce scatter radiation in the remnant x-ray beam
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Grid
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physical area of the target that is bombarded by electrons during tray production
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focal spot
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area over which electrons from the cathode strike the target
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focal spot
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a metal that abruptly decelerates & stops electrons in the tube current
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tungsten
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a devise used t measure optical densities
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densitometer
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focus the stream of electrons
made of ? charge? |
focusing cup
nickel negative |
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measure of the maximum electrical potential across an x-ray tube
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kVp
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images too light ( not enough density) to be diagnostic
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underexposed
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to correct underexposed images
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increase mAs
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refers to the " absorbing ability" of the structure in the path of the x-ray
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subject contrast
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energy loss during the braking slowing is emitted as this type of x-ray photon
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bremsstrahlung
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as long as mAs stays constant
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any combination of mA and time
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200 mA and 0.5 sec. will provide what mAs
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100
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the intensity of radiation @ a given distance from a pt source is inversely proportional to the square of the distance
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inverse square law
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tiny particles that have a negative electrical charge
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electrons
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has positive electrical charge
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protons
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neutral charge ...no charge
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neutrons
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limits # of electrons that can escape from the filament
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space charge effect
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occurs when electrons interact w/ an inner shell electrons (k shell only )
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characteristic interaction
15% increase 70 kvp |
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majority of x-rays interactions produce in diagnostic radiology result from this interaction
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bremsstrahlung
Brem 85% above kvp |
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from long scale to short
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kvp increase and density increase and vis versa
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increase kvp by 15%
reduce kvp by 15% |
double mAs
cut density in half |
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overexposed
underexposed |
cut mas in half
double mas |
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to emit electrons when heated
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filament
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lead-lined prevents leakage radiation from escaping & provides structure for x-ray tube
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protective tube housing
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is determined by the filament size
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focal spot size
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positively charged electrode of the x-ray tube contains stator, rotor, and target
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anode
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anode material that conducts heat from target
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molybdenum (moleleddicum)
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called cold cathode x-ray tube
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crooks tube
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hot cathode tube has full vacuum
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Coolidge tube
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window / port is made of this material allows primary beam to escape beam
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beryllium
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used in low out put clinical circumstance such as central x-ray machine
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stationary anode target
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used to eliminate exposure of body regions not required in image
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collimator
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makes tungsten flexible and resistant to wear from impact of the electron beam
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rhenium
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a device that receives the radiation leaving the pt
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image receptor
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exposed in seconds or milliseconds
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exposure time
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distance from an object or a specific portion of the object to the imaging receptor
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OID object - image distance
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the flexible plate inside the CR cassette where the photon intensities are absorbed by the phosphor
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imaging plate (IP)
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radiation which has changed direction from the primary beam and towards in random directions
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scatter radiation
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product of mA and time
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mAs
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radiation generated in the x-ray tube that does not exit from the port but rather penetrates through the protective housing
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leakage radiation
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device used to reduce scatter radiation in the remnant x-ray beam
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grid
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the distance b/w 2 successive crests or troughs
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wave lengths
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the ability of phosphors to emit visible light only when exposed to x-ray
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florescence
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a form of energy that moves in waves that have wave lengths and frequency
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electromagnetic radiation
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a small dis create bundle of energy
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photon or quantum
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the # of waves passing a given pt. per given unit of time
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frequency
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mAs
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density
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higher energy x-rays have decreased wave length and increased frequency
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true
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an image w/ high contrast is to be long scale
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false
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xrays have a dual nature, which means that they behave like both charged and uncharged particles
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false
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the negatively charged electrons of the x-ray tube
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cathode
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xrays have a positive charge
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false neutral
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the xray beam used in diagnostic radiography can be described as being poly energetic
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true
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an increase in mAs will increase density
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true
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