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RAD BIO ch 9 bushongs
Terms in this set (59)
____ occurs because of compton scatter, photoelectric effect, and x-ray transmission
5 ways x-rays interact
compton scatter and photoelectric
only ____ are important in making an x-ray image
the interaction between electromagnetic radiation and matter has ___ and ___ properties
similar in size
Electromagnetic radiation interacts with structures that are_____ to the wavelength of the radiation.
x-rays have ____ wavelengths (10^-8 to 10^-9m)
The _____the energy of an x-ray, the _____is its wavelength.
low-energy x-rays tend to interact with _____, which have diameters of approximately 10−9 to 10−10 m
moderate-energy x-rays generally interact with _____
high-energy x-rays generally interact with _____.
X-rays with energies below approximately 10 keV (low energies) interact with matter by ____, sometimes called classical scattering or Thompson scattering
in coherent scattering, a target atom immediately releases excess energy (scatter) with wavelengths that are ____ to that of the incident ray
in coherent scatter, the direction of the x-ray changes (usually forward) without a change in its ____; therefore NO IONIZATION occurs
Coherent Scatter diagram
At 70 kVp, a few percent of the x-rays undergo coherent scattering, which contributes slightly to ____
X-rays throughout the diagnostic range can undergo an interaction with outer-shell electrons that not only scatters the x-ray but reduces its energy and ionizes the atom as well. This interaction is called ____
In Compton scattering, the ejected electron is called a ____. The x-ray continues in a different direction with less energy.
equal to the difference between the energy of the incident x-ray and the energy of the ejected electron.
The energy of the Compton-scattered x-ray is _____; the scatter usually retains most the energy
Ei = Es (Eb + EKE)
In compton scattering, the energy of the ejected electron is equal to its binding energy plus the kinetic energy with which it leaves the atom
In compton scattering, both the scattered x-ray and the compton electron may continue to ____ till they lose all energy, and will ultimately be absorbed photoelectrically
In compton scatter, if a deflection of____occurs, no energy is transferred
X-rays scattered back in the direction of the incident x-ray beam are called ____
the probability of compton scatter ____ as x-ray energy ____; it is inversely proportional to x-ray energy
atomic number of the atom involved
The probability of Compton scattering does not depend on the ____
Compton scattering reduces ____ by producing optical density
no useful information
Scattered x-rays provide ____ on the radiograph
as mass density of absorber ____, compton scatter ____
____ is the source of most of the occupational radiation exposure that radiographers receive.
The x-ray is not scattered, but it is totally absorbed; Ei = Eb + EKE
the photoelectric effect earned ____ the 1921 Nobel Prize in physics
The electron removed from the atom, called a ____, escapes with kinetic energy equal to the difference between the energy of the incident x-ray and the binding energy of the electron.
____x-rays are produced after a photoelectric interaction
characteristic x-rays consist of _____
do not penetrate to the image receptor
characteristic x-rays have such low energy that they _____
x-ray energy, atomic number of which it interacts
photoelectric interactions depend on the ____ and the ____
electron binding energy
A photoelectric interaction cannot occur unless the incident x-ray has energy equal to or greater than the ____
atomic number of the absorbing material (Z3), 3rd power of the x-ray energy
The probability of photoelectric effect is directly proportional to the third power of the____ and inversely proportional to the ____
The interaction between the x-ray and the nuclear field causes the x-ray to disappear, and in its place, two electrons appear, one positively charged (positron) and one negatively charged
as mass density of an absorber increases, photoelectric absorption ____
An x-ray with less than ____ cannot undergo pair production
distributed equally between the two electrons as kinetic energy.
in pair production Any of the x-ray's energy in excess of 1.02 MeV is ____
in pair production, The positron unites with a free electron, and the mass of both particles is converted to energy in a process called ____
pair production is very important for positron emission tomography imaging in ____
X-rays with energy above approximately 10 MeV can escape interaction with electrons and the nuclear field and be absorbed directly by the nucleus.
bremsstrahlung and characteristic
the 2 methods of x-ray production are
absorption and transmission
the difference in ____ is the differential absorption
____of the x-rays incident on a patient reach the image receptor.
the radiographic image results from approximately ____of the x-rays emitted by the x-ray tube.
kVp is reduced.
Differential absorption increases as the____; therefore the contrast on the image increases and so does patient dose
With higher x-ray energy, ____interactions occur, so ____ x-rays are transmitted without interaction.
To image small differences in soft tissue, one must use ____ to get maximum differential absorption.
do not affect
Grids do not affect ____the magnitude of the differential absorption; they clean up scatter from soft tissue scatter
a ____ beam contains x-rays that all have the same energy
clinical x-rays are ____. They are emitted over an entire spectrum of energies.
air has higher Z than soft tissue because it has more____.
The total reduction in the number of x-rays remaining in an x-ray beam after penetration through a given thickness of tissue is called ____.
absorption and scattering
Attenuation is the product of ____.
alpha and beta
particulate particles that can only penetrate so far before being absorbed
THIS SET IS OFTEN IN FOLDERS WITH...
RadBio CH 29 Human Biology
RADBIO CH 25 (B)
RAD BIO chapter 36 (B)
RAD BIO ch 30
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