Ch 1, 2, 3
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
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| List 7 Characteristics of X-rays: | * Invisible
* Electrically neutral
* No mass
* Cannot be optically focused
* Travel @ speed of light in vaccum
* Form a polyenergetic beam
* Can be produced in a range of
energies
* Can cause some substances to
fluoresce
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| List 7 more Characteristics of X-rays | * Travel in a straight line
* Can cause some substances to
fluoresce
* Cause chemical changes in
radiographic & photographic film
* Can penetrate body
* Can be absorbed or scattered in
the body
* Can produce secondary radiation
* Can dam
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| What is the medically useful diagnostic range of x-ray energies? | 30 to 150 kVp
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| In what year were x-rays discovered? | 1895
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| What is the speed of light? | 3 x 10 to the eighth
or 186,000 mph.
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| In what year were some of the biologically damaging effects of x-rays discovered? | 1898
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| X-rays were discovered in experiments dealing with: | the conduction of high-voltage electricity through low-vacuum tubes
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| X-rays were discovered when they caused a barium platinocyanide-coated plate to: | fluoresce
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| X-radiation is part of which spectrum? | electromagnetic
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| X-rays have a dual nature, which means that they behave like both: | waves and particles
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| How are the wavelength and frequency of x-rays related? | inversely
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| Who won the 1st Nobel prize in physics in 1901? | Wilhelm Conrad Roentgen
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| How fast does a rotating anode spin? | 3,000 to 10,000 rpm
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| What is the atomic number of tungsten? | 74
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| What is a mammography target made of? | Molybdenum - atomic #42
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| Where to the majority of heat come from in x-ray production? | the anode
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| What percent of the primary beam reaches the image receptor? | 5%
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| The physical area of the target that is bombarded by electrons during x-ray production? | Focal spot
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| The actual focal spot and effective focal spot are related: | Directly
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| What is the advantage of a rotating anode verses a stationary anode? | Rotating anode dissipates heat better
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| What is the acceptable leakage radiation? | 100 mR per hr no more than 1 meter from the source
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| What is the Source-to-skin distance requirements? | Shall not be less than 12 inches and should not be less than 15 inches
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| What percentage of interactions above 70kVp are Bremsstrahlung? | 85%
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| What percentage of interactions below 70kVp are Bremsstrahlung? | 100%
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| Produced when a projectile electron interacts with an electron from the inner shell (K-shell) of the tungsten atom | Characteristic interactions
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| A German word meaning "braking" or "slowing down" | Bremmstrahlung
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| True or False: There is no difference between a Bremsstrahlung interaction and a Characteristic interaction at the same energy level. | True
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| What determines the speed at which the electrons in the tube current move? | kVp
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| What is the unit used to measure the tube current? | milliampere (mA)
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| Coiled tungsten wire that is the source of electrons during x-ray production | filament
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| What is made up of nickel & nearly surrounds the filament? | focusing cup
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| Allows electrons to flow freely across the tube from the cathode to the anode | focusing cup
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| positively charged electrode | anode
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| a metal that abruptly decelerates & stops electrons coming from the tube current, thereby allowing the production of x-rays | target
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| What is the target of rotating anode tubes made of? | Tungsten
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| Atomic # of tungsten | 74
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| What is the melting point of tungsten? | 3370 C
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| In mammography, what is the target made of? | Molybdenum
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| Atomic # of molybdenum | 42
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| What has a high melting point, but produces a much lower x-ray beam? | Molybdenum
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| Number of waves passing a given point per given unit of time. | Frequency
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| What is the difference between Bremstrahlung & Characteristic x-rays at the same energy level? | There is no difference, they are just different processes.
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| What turns the rotor at a very high speed? | stator
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| What rotates rapidly during x-ray production? | rotor
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| The physical area of the target that is bombarded by electrons during x-ray production. | focal spot
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| Any x-rays other than the primary beam that escape the tube housing. | leakage radiation
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| In what direction do electrons travel? | cathode to anode
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| How fast do electrons travel? | half the speed of light
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| What 2 interactions produce x-ray photons? | Bremsstrahlung & Characteristic
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| German word that means "breaking" or "slowing down" | Bremsstrahlung
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| Focal spot size as measured directly under anode target | Effective focal spot size
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| True or False: The amount of anode angle determines the size of the focal spot. | True
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| Describes how x-ray intensity is greater on cathode side, with the intensity diminishing | Anode heel effect
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| How is mAs calculated? | mA x s
milliamperage x seconds
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| Doesn't allow any more electrons to be boiled off the filament. | space charge effect
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| What is the ejected electron in Compton effect called? | compton electron or recoil electron
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| single-phase factor | 1.0
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| The amount of heat produced from an exposure is expressed by the... | heat unit
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| What factors do radiographers select to produce a quality image? | * kilovoltage (kVp)
* milliampere (mA)
* exposure time
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| How is mAs calculated? | mA x s
milliamperage x seconds
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| Doesn't allow any more electrons to be boiled off the filament. | space charge effect
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| What is the ejected electron in Compton effect called? | compton electron or recoil electron
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| single-phase factor | 1.0
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| The amount of heat produced from an exposure is expressed by the... | heat unit
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| What factors do radiographers select to produce a quality image? | * kilovoltage (kVp)
* milliampere (mA)
* exposure time
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| Allows imaging movement of internal structures. | fluoroscopy
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| invisible until processed | latent image
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| visible image | manifest image
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| positively charged electrode | anode
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| How are the quantity of electrons that flow from cathode to anode & the quantity of x-rays produced related to exposure time? | they are directly proportional
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| The most important part of the x-ray machine because it is where x-rays are produced. | x-ray tube
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| Describes how x-ray intensity is greater on cathode side, with the intensity diminishing toward the anode side. | Anode heel effect
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| x-rays are also called | photons
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| A radiographic image is created by passing an x-ray beam through the patient & interacting with the | image receptor
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| True or False: At higher kilovoltages, fewer photon interactions occur, resulting in more x-ray transmissions. | True
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| What percentage of electrons in the tube current is converted to heat? | 99%
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| What kind of paper was Roentgen using when he discovered x-rays? | barium platinocyanide
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| Absorption is similar to what interaction? | Characteristic
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| negatively charged electrode | cathode
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| focuses electrons | electrostatic lenses
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| Flow of electrons from cathode to anode | tube current
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| Process where some of the x-ray beam is absorbed in the tissue & some passes through the body | Differential absorption
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| True or False: The more mA, the more x-rays produced | True - they are directly related
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| How are wavelength and frequency related? | inversely
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| Three types of x-ray generators: | * Single-phase
* Three-phase 6 pulse
* Three-phase 12 pulse
* High frequency
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| Type of double-wedge filter used for AP projection of the thorax | trough filter
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| How fast is the speed of light? | 3 * 10^8 meters per second
186,000 miles per second
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| X-ray tubes operating above 70 kVp must have a minimum total filtration of ______ or its equivalent | 2.5 mm of aluminum
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| What percentage of electrons in the tube current are converted to x-rays? | 1%
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| Type of double-wedge filter used for AP projection of the thorax | trough filter
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| How fast is the speed of light? | 3 * 10^8 meters per second
186,000 miles per second
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| X-ray tubes operating above 70 kVp must have a minimum total filtration of ______ or its equivalent | 2.5 mm of aluminum
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| What percentage of electrons in the tube current are converted to x-rays? | 1%
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| Incoming x-ray photon passes through the anatomic part without interactions | transmission
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| What kind of relationship does the speed of electrons traveling from cathode to anode have with kilovoltage? | direct relationship; speed of electrons increase as kilovoltage increases
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| Heat unit equation | HU = mA * time * kVp * gen. factor
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| Boiling off of electrons from the filament | thermiotic emission
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| What is made of nickel & nearly surrounds the filament? | focusing cup
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| Coiled tungsten wire that is the source of electrons during x-ray production | filament
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| Occurs with low energy x-rays; photon interacts with atom & excites it; the atom DOES NOT lose energy, but it does change direction | Coherent scattering
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| cloud that forms around filament after thermiotic emission | space charge
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| Three-phase 6 pulse factor | 1.35
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| Three-phase 12 pulse | 1.41
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| Filtration added to the port of the x-ray tube | Added filtration
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| Most common type of compensating filter - thicker portion is lined up with thinner portion of body | wedge filter
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| When the attenuated x-ray beam leaves the patient, the beam is called | exit radiation
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| During this interaction, projectile electrons interacts with k-shell electron & produces a "cascading" effect which produces x-ray photons | Characteristic interaction
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| What heats the tungsten filament? | filament current
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| filtration permanently in the path of the x-ray | inherent filtration
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| the amount of filtration that reduces the intensity of the x-ray to 1/2 its original value | half-value layer
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| radiation that has both electrical & magnetic properties | electromagnetic radiation
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| creates brighter image | output phosphor
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| any x-rays other than the primary beam that escape the tube housing | leakage radiation
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| tube current is measured in | mA
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| Incoming photons are not absorbed, but they lose energy during interaction in the body | scattering
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| When does complete absorption occur? | when incoming x-ray photon has enough energy to remove the inner shell electron
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| Components that contribute to inherent filtration: | * glass envelope
* oil that surrounds tube
* mirror inside collimator
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| can be added to the primary beam to alter intensity | compensating filters
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| What is used to determine whether a particular exposure will be safe to make? | instantaneous load tube rating chart
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| Bremsstrahlung Interaction | electron avoids orbital electrons & get close to nucleus & changes directions
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| polyenergetic beam that consists of a wide range of energies | x-ray emission spectrum
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| focal spot size as measured directly under anode target | effective focal spot size
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| interactions that can occur within all diagnostic x-ray energies | Compton interactions
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| allows electrons to flow freely across the tube from the cathode to the anode | focusing cup
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| What exposure factors allow the x-ray beam to be altered? | * quality
* quantity
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| What do low energy photons do? | Contribute to patient dose. They do NOT contribute to image formation.
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| radiation measuring device | dosimeter
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| distance between two successive crests or troughs | wavelength
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| The ejected electron resulting from total absorption of the photon during the photoelectric effect interaction. | photoelectron
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| the ability of an x-ray photon to remove an electron | ionization
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| In what year did they discover that x-rays could cause biological damage? | 1898
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| converts light to electrons | photocathode
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| What converts exit radiation photons to visible light in the image intensifier? | input phosphor
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| Interaction where energy scatters and changes direction | Compton effect
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| Process in which exit radiation from the area of interest interacts with light emitting material | image intensification
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| What is x-ray energy measured in? | kiloelectron volts (kev)
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| density on the x-ray is equal for any combination of mA & time as long as the product is equal | mAs reciprocity
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| High frequency generator factor | 1.45
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| Product of both flux/minification gain | Brightness gain
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| When ionization occurs in the diagnostic range | Photoelectric effect
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| What is exit radiation composed of? | * transmitted radiation
* scattered radiation
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| Added filtration and inherent filtration | total filtration
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| What kind of tubes was Roentgen working with when he discovered x-rays? | Crookes tubes
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| Reduction in the energy of the primary beam | attenuation
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| refers to the instantaneous production of light resulting from the interaction of some type of energy & some element/compound | fluorescence
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| What determines the length of time that the x-ray tube produces x-rays? | exposure time
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| size of the area on the anode target that is exposed to electrons from the tube current | actual focal spot
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| the relationship between the actual focal spot & the effective focal spot | Line-focus principle
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| What relationship does kVp and penetrability have? | Direct relationship: as kVp increases, penetrability increases
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| What is the device that receives the radiation that exits the patient to create the radiographic image? | image receptor
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| What are some factors that affect the beam interaction? | * quantity of primary beam
* quality of primary beam
* composition of the anatomic tissues
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| The process of image formation is a result of: | differential absorption
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| What is the process whereby some of the x-ray beam is absorbed in the tissue and some passes through the anatomic part? | differential absorption
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| What does the word "differential" mean? | varying
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| Does differential absorption increase or decrease as kVp is reduced? | increase
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| What are the processes that occur during beam attenuation? | * absorption
* scattering
* transmission
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| The variations between _______ and __________ of the exiting x-ray beam will structurally represent the anatomic area of interest. | absorption and transmission
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| The reduction in the energy of the primary beam is known as: | attenuation
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| When absorption takes place, what is the ejected electron called? | photoelectron
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| A total x-ray absorption interaction | Photoelectric Effect or Photoelectric Interaction
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| Photoelectric interaction results in areas in the radiograph that are ____. This means that the resulting image will possess ______ density. | light
low
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| Probability of total photon absorption is dependent on: | * the energy of the incoming x-ray
photon
* the composition of the anatomic
tissue
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| What is the ability of an x-ray photon to remove an electron? | ionization
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| The photoelectric effect if responsible for total ________ of the incoming x-ray photon. | absorption
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| The energy of the incoming x-ray photon must be at least _____ to the binding energy of inner shell electrons. | equal
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| True or False: The overall energy of the primary beam increases as it passes through the anatomic part. | False
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| The process of ________ means that the photons lose energy and are not absorbed during interaction; instead, the photon changes direction. | Compton scattering
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| _____ is an outer shell electron interaction. | Compton effect
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| The electron that is ejected during the compton effect is called a | compton electron or recoil electron
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| During the process of Compton scattering, the incident photon continues on an altered path, scattered, with less energy and a _____ wavelength than before the collision. | longer
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| True or False: Scattered radiation contributes to radiation dose to the patient and provides useful information about the anatomic area of interest. | False
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| The percentage of Photoelectric interactions _______ at a higher kilovoltage. | decrease
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| The percentage of Compton interactions _______ at higher kilovoltage. | increase
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| If the incoming x-ray photon passes through the anatomic part without any interaction with the same atomic structures, it is called: | transmission
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| Transmission is more likely to occur with ________ kVp. | high
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| The incoming x-ray photons that are transmitted create the _______ areas on the radiograph and the resulting image will produce _______ density. | dark / high
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| True or False: The quality of the image created is compromised if the scattered x-ray photon strikes the image receptor. | True
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| Radiation that leaves the patient is called: | exit radiation
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| Exit radiation consists of ________ and ________ radiation. | transmitted and scattered
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| Scatter radiation creates unwanted density on the image called: | fog
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| What percentage of the primary x-ray beam actually reaches the image receptor? | less than 5%
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| The x-ray beam that reaches the image receptor creates the ______ or invisible image. | latent
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| Developing and processing an exposed film produces the _______ image. | manifest
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| Anatomic tissues that vary in absorption and transmission create the ___________ on the image. | range of densities
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| Imaging the movement of internal structures is known as: | fluoroscopy
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| What is the process in which the exit radiation form the anatomic area of interest interacts with a light emitting material for conversion to visible light? | image intensification
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| The light emitting material is called | input phosphor
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| Which image intensifier component converts the visible light intensities from the input phosphor to electrons? | photocathode
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| What is the purpose of electrostatic focusing lenses? | to focus electrons into a narrow stream toward the output phosphor
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| The image light intensities from the output phosphor are converted to an __________ and sent to a TV monitor for viewing. | electronic video signal
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| What are the 2 types of digital radiography that is commonly used today? | CR - Computed radiography
DR - Direct digital radiography
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| True or False: Regardless of whether the imaging is CR or DR, the computer can manipulate radiographic image in a variety of ways. | True
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| In digital imaging, the latent image is stored as ________ and must be processed by computer for viewing. | digital data
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| True or False: The process of differential absorption is different on each type of image receptor. | False
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