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80 Cards in this Set
- Front
- Back
how does image production work |
photons pass through tissue and interact with the image receptor |
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what is an image receptor |
a device that receives the radiation leaving the patient |
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what affects the primary x-ray beam interaction with the various tissues that make up the anatomic part |
quantity and quality of the beam |
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___________ of the anatomic tissues affects the beam interaction |
composition |
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composition of anatomic tissues |
thickness, atomic number, tissue density |
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what determines absorption characteristics of anatomic parts |
its composition |
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how is the late image formed |
radiation exits the patient and is composed of varying energies and interacts with the IR |
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as the primary beam passes through anatomic tissue, it loses some of its energy. This reduction in the energy or number of photons in the primary x-ray beam is known as what |
beam attenuation |
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beam attenuation occurs as a result of what |
the photon interactions with the atomic structures that compose the tissue |
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when does complete absorption of the incoming x-ray photon occur |
when it has enough energy to eject an inner-shell electron |
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what is the name of the electron that is ejected from the inner-shell during complete absorption |
photoelectron |
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quickly loses energy by interacting with nearby tissue |
photoelectron |
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what is ionization
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the ability to eject electrons |
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in the diagnostic range the ability to eject electrons is known as |
the photoelectric effect |
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with the _____________ ______ the ionized atom has a vacancy or electron hole in its inner shell. An election from an _____-_____ drops down to fill the vacancy |
photoelectric effect outer-shell |
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for photoelectric events to occur, |
the incident x-ray energy must be equal or greater than the orbital shells binding energy the incident x-ray photon interacts with the inner-shell electron of a tissue atom and remove it from orbit |
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in this process the incident x-ray photon expends all of its energy and it totally absorbed |
photoelectric effect |
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when incoming photons are not absorbed,but instead lose energy during interaction with the atoms composing the tissue its called __________ and is a result of _______ ______ |
scattering compton effect |
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results from the diagnostic x-ray interaction known as the compton effect
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scatter |
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the loss of some energy of the incoming photon occurs when it ejects an outer-shell electron from a tissue atom. The ejected electron is called a |
compton electron or secondary electron |
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in the compton effect the remaining low energy photon changes direction and may do what |
leave the anatomic part to interact with the IR |
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does scatter contribute to useful information to the image, why or why not |
no, it only results in image fog |
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why is it desired to minimize compton scatter |
because most scattered photons are still directed towards the IR and fog the image |
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why are compton interactions important in radiography |
because they can occur within all diagnostic x-ray energies |
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the probability of a commton interaction occurring depends on what |
the energy of the incoming photon |
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does common interaction depend on anatomic tissue |
no |
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incoming photon has sufficient energy to eject an inner-shell electron and be completely absorbed |
photoelectric effect |
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incoming photon loses energy when it ejects an outer-shell electron and changes direction |
compton effect |
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an electron from an outer-shell fill the electron hole or vacancy in |
the photoelectric effect |
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the scattered photon may be absorbed within the patients tissues, leave the anatomic part, interact with the image receptor, or expose anyone nearby in |
the compton effect |
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a secondary photon is credited because of the difference in binding energies in |
the photoelectric effect |
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scattered photon strike the IR and provide no useful information in |
the compton effect |
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the probability of the photoelectric effect depends on what |
the energy of the incoming x-ray photon and the composition of the anatomic tissue |
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fewer photon interactions happen at _____ kVp settings, but of those interaction, a smaller percentage are _____________ ____________ |
higher photoelectric interactions |
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when does coherent scattering |
with low-energy x-rays, typically below the diagnostic range |
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what happens in coherent scattering |
the incoming photon interacts with the atom, causing it to become excited. The x-ray does not lose energy but changes direction |
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is coherent scatter considered an important interaction in radiography |
no |
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what is it called if the incoming x-ray photon passes through the anatomic structures without the anatomic structures, it is called |
transmission |
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the combination of __________ and____________ of the x-ray beam provides an image that structurally represents the anatomic part |
absorption and tranmission |
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what factors affect beam attenuation |
tissue thickness, type of tissue, and x-ray beam quality |
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x-ray are attenuated ___________ and generally reduced by __% for every _-_ cm of tissue thickness |
exponentially 50% 4-5 |
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the _______ the anatomic tissue the more x-ray are needed |
thicker |
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tissue with a higher ______ ______ attenuates the -ray beam more than tissues with lower ______ _______ |
atomic number atomic numbers |
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what does higher atomic number of tissue indicate |
there are more atomic particles to absorb or scatter the x-ray photon |
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absorption is not likely to occur in tissues with a higher atomic number tor f |
false |
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tissues that absorb more x-rays demonstrate what on film and what in digital |
light areas on film greater brightness in digital |
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tissues with more transmission demonstrate what on film and what in digital |
darker on film less brightness in digital |
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how does tissue density affect beam attenuation |
the more dense the more attenuation |
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during x-ray production what determines the energy or penetrability of the x-ray photon and its attenuation in anatomic tissue |
kVp |
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what energy x-ray beam decreases beam attenuation and what increases it |
higher energy x-ray beam lower energy x-ray bean |
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higher penetrating x-ray are more likely to |
be transmitted though anatomic tissue without interacting with the tissues' anatomic structures |
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higher penetrating x-rays are _____ in wavelength and _____ in frequency |
shorter higher |
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lower penetrating x-rays are more likely to |
interact with the anatomic structures and either be absorbed or scattered |
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lower penetrating x-rays are ______ in wavelength and _____ in frequency
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longer lower |
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what percentage of the x-ray beam interacting with the anatomic part reaches the IR how much is used to create the radiographic image |
less than 5% reaches the IR and an even less percentage of that creates the image |
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what creates the latent image |
the exit or remnant radiation leaving the patient interacts with an IR to create the latent image |
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how do you produce the manifest image |
by processing the film |
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how many types of IR are there and what kind of image do they produce |
two types: film/screen and digital and they both produce static images of the area of interest |
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what type of IR uses a cassette for the film and the film is placed between two intensifying screens within the cassette |
film/screen |
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what is a cassette |
light-tight container |
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when exit radiation interacts with the intensifying screens in film/screen what is it converted too |
light |
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the visual light emitted by the intensifying screen is proportional to what |
the radiation exiting the patient |
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why can less radiation be used when using film/screen |
because of the intensifying screens |
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do intensifying screens reduce patient exposure |
yes |
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what type of imaging can be accomplished by using a specialized IR that acquires the latent image and then the computers processes the manifest image for monitor display |
digital imaging |
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there is only one type of IR used for digital imaging t or f |
no there are several |
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film acquires, process, and displays image |
film/screen |
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IR acquires, computer processes, monitor displays |
digital |
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reguardless of the type of digital IR the image is composed of digital data and can be manipulated t or f |
true |
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how does fluoroscopy differ for static imaging |
it uses a continuous beam of x-rays to create images go moving internal structures that can be viewed on a monitor |
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internal structures, such as vascular or gastrointestinal systems, can be visualized in their normal state of motion with the aid of ________ _____ that are ________ or ________ |
contrast media injected or ingested |
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in fluro internal images can be best visualized when the images are brighter, which is accomplished with _____ _______________ |
image intensification |
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what is image intensification |
the process in which radiation from the anatomic area of interest interacts with a light-emitting material (input phosphor) for conversion to visible light |
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in image intensification the light intensities (________) are equal to the intensity of the ____ _________ and are converted to _________ by a ____________ |
energies exit radiation electron photocathode |
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in image intensification the electrons are focused by _____________ ________ ______ and the accelerated toward an _____ to strike the output phosphor and create a ________ _____ (__________ ____) |
electrostatic focusing lenses anode brighter image brightness gain |
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accelerating the electrons increases the light intensities at the output phosphor is what |
flux gain |
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the reduction in the size of the output phosphor image as compared with input phosphor also increases the light intensifies is what |
minification gain |
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what is brightness gain |
the product of flux gain and magnification gain and results in brighter image on the output phosphor |
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In what are the image light intensities from the output phosphor are converted to an electronic video signal to display for monitor viewing |
dynamic IR: Fluoroscopy |
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what additional filming devices can be attached to the fluoroscopic system to create permanent radiographic images of specific areas of interest |
spot film or cine |