Exam II Flashcards
If the distance from the source is changed from 72” to 36” and the original intensity was 200mR, what is the new intensity?
800 mR
When filament electrons enter the anode target, they interact with
Outer shell electrons of tungsten atoms
The x-axis for all emission spectra represents the
Energy levels of the photons
Increasing the kVp results in
An increase along the y-axis and a shift to the right along the x-axis
The purpose of beam filtration is to
Reduce patient dose.
During the bremsstrahlung interaction, the filament electron
Is attracted to the nucleus not absorbed
Changing from a high frequency generator to a single phase generator in the x-ray emission spectrum
Both: changes along the x-axis and y-axis
True or False:
When the kVp is changed from 60 to 120, the discrete line on the x-ray emission spectrum shifts to the right.
False
If a filament electron leaves the tungsten atom with 15 keV of energy and the brems photon produced is 65 keV, how much energy did the incoming filament electron have?
80 keV.
Adding filtration in the path of the beam results in the x-ray emission spectrum
Both: Changing along the x-axis and the y-axis
The energy of the characteristic x-ray photon depends on:
All of these.
The binding energy of the inner shell electron, the energy level of the filament electron, and the shell of the electron that is dropping into the vacancy.
One HVL reduces the intensity of the x-ray beam to ______ of its original
One half
Changes along the x-axis of the x-ray emission spectrum reflect changes in ___ of the x-ray beam
Quality
True or False
HVL is described as a certain amount of tungsten or its equivalent that will reduce beam intensity by one half.
False
The x-ray emission spectrum is a graphic illustration of
Characteristic radiation and bremsstrahlung radiation.
The process of a series of outer-shell electrons filling inner-shell vacancies right after the other is called
Characteristic cascade
Changing the _____ results in changes to the x-axis, y-axis, and location of the discrete line of the x-ray emission spectrum
Target material
If kVp is doubled, the quantity of radiation increases by a factor of
4
A continuous emission spectrum is a graphic representation of
Bremsstrahlung radiation
Filtration placed in the path of the x-ray beam
Absorbs low-energy photons.
If filament electron enters the tungsten atom with 80 keV of energy and leaves the atom with 75 keV energy:
The filament electron traveled very far from the nucleus
With a 75 kVp exposure,the peak of the curve on the continuous emission spectrum is approximately
25 keV
The y-axis for all emission spectra represents the
Number of photons
If the distance is doubled, the quantity of radiation reaching a specific area is ____ the original
One fourth (1/4)
A filament electron removes a k shell electron and an M shell electrons fills the vacancy. The k shell binding energy is 69.5 keV and the M shell binding energy is 2.8 keV. What is the energy of the k-characteristic photon produced?
66.7 keV
To double the beam quantity
Double the mAs
It is recommended that kVp not be used to control beam quantity because
All of the above.
It affects scatter production
It affects penetrability of a beam
it is less predictable in how changing the kVp affects the image
The beam that is found leaving the collimator and exposes the patient is called the
Primary beam
Beam quality refers to
The energy level of the radiation
A higher energy beam is said to be a
Hard beam
Placing filtration in the path of the beam results in
A harder beam
During x-ray production the electrons penetrate the target approximately
0.5mm
To increase the quantity of radiation by adjusting the kVp to the same level as doubling the mAs, increase kVp by a factor of
15%
Half value layer (HVL) is used to measure
Beam quality
X-rays are produced by
Characteristic and bremsstrahlung interations
The remnant radiation that have an interaction with an anatomic structure is
Scattered radiation
If the intensity of the beam is 900 mR at a distance of 21 inches, what does the distance need to be for the intensity to measure 100mR?
63”
The discrete emission spectrum typically displays
Both K and L characteristic photon energies
Which of the following factors affect beam quantity?
All
-kVp
-Distance
-Filtration
Which of the following results in the equivalent of doubling the mAs if the original kVp is 80?
92 kVp
True or False:
A 65 keV filament electron is not able to produce characteristic radiation
True.
To produce characteristic radiation, the electron’s energy must be greater than the orbital electron’s binding energy.
The x-ray beam that leaves the patient to expose the IR is called the
Remnant beam
The remnant radiation that did not interact with any anatomic structure is
Transmitted radiation
L-characteristic and higher photon energies are not usually displayed on a discrete emission spectrum because
The energies of the photons are too low for image formation
True or False
The probability of Compton scattering depends on the atomic number of the atom.
The x-ray photons that are produced as a result of a characteristic cascade during a Compton interaction
are characteristic x-ray photons.
Secondary photons produced during a Compton interaction
contribute to patient dose.
The Compton electron
has enough energy to produce further interactions.
For photoelectric interactions to occur, the energy of the incident photon
may be the same or greater than the binding energy of an inner-shell electron.
True or false
Deoxyribonucleic acid (DNA) is the most sensitive human cell molecule.
True
After ejection from the atom’s nucleus, when the positron interacts with an electron
all of these.
The fog seen on the radiographic image is the result of
Compton interactions
Compton scattering typically occurs with x-ray photons in the energy range of
20-40
The Compton scatter photon
may exit the patient as part of the remnant radiation and has enough energy to produce further interactions.
Pair production
never occurs during radiographic procedures
A positron is
a positively charged electron.
Compton scattering results in
All of these
The energy of the photoelectron is the least as a result of a photoelectric interaction in
Bone
True or False
Irradiation of water can create harmful free radicals that then indirectly damage molecules and cells.
True
True or False
The photoelectric interaction and Compton interaction can both result in a characteristic cascade, producing characteristic radiation.
True
True or False
All Compton scatter photons travel in the direction of the image receptor.
False
The greater the absorption of radiation
the greater the patient dose.
The energy of the photoelectron is equal to
the energy of the incident photon minus the binding energy of the orbital electron.
When it does interact with the image receptor, the Compton scatter photon contributes no useful information because
it has changed direction.
The primary source of radiation exposure to the radiographer who is in the room during an exposure is
from scatter from the patient.
With Compton scattering, the incident photon
loses up to one third of its energy.
True or False
Potential biological damage can occur as a result of a Compton interaction because of the ionization of atoms.
True
Compton scattering involves the x-ray photon
removing a middle- or outer-shell electron.
The greater the angle of deflection of a Compton scatter photon:
the lower the energy of the photon.
True or False
The probability of Compton scattering depends on the atomic number of the atom.
False
Pair production occurs when the incident photon interacts with
the nucleus of the atom
Compton scattering typically occurs with
moderate-energy photons.
Photodisintegration occurs when the incident photon interacts with
the nucleus of the atom.
Dense material, like bone, is considered:
radiopaque.
During a photoelectric interaction,
an inner-shell electron is ejected.
Barium sulfate is used as a contrast agent to visualize soft tissue structures such as the stomach because it
has a high atomic number.
The end product(s) of a photoelectric interaction is (are)
a photoelectron and an ionized atom.
In reference to patient radiation dose, classical scatter interactions
slightly increase dose.
The x-ray photon produced during classical scattering
is the same energy as the incident photon.
Most classical scatter photons
are absorbed in the body.
No matter which direction the Compton scatter photon goes, it retains approximately
two thirds of its energy.
The major source of radiation exposure to technologists is due to
Compton interactions
True or False
The more the energy of the incident x-ray photon exceeds the binding energy of the inner-shell electron, the greater the probability of a photoelectric interaction.
False
For photodisintegration to occur, the incident photon must have an energy level of at least
10 mev
What is produced as a result of pair production, a(n)
positron and electron only.
Protective apparel is often made of lead because it
has a high atomic number
To produce a radiographic image that represents anatomy, there must be
All of these
True or False
Without differential absorption, the image would be a single shade of gray.
True
Photodisintegration interactions
never occur during radiographic procedures.
If a middle-shell electron is removed during a Compton interaction
All of these
Coherent scattering involves
an x-ray photon with low energy.
To minimize occupational exposure, the technologist should
wear protective apparel (lead aprons, gloves, etc.) when in the room during imaging.
Reducing the amount of Compton scattering
all of these.
True or False
The probability of a photoelectric interaction depends on the atomic number of the atom.
True
Air is considered
Radiolucent
Following absorption of the incident photon in the atoms nucleus, a photodisintegration interaction may result in
neutrons and protons being ejected from the nucleus
Photoelectric interactions
Contribute significantly to patient dose
true or false
the higher the atomic number of an atom, the greater the probability of a photoelectric interaction
true
radiation interacting with air is more likely to be ___ resulting in that area of the image being darker
transmitted
photoelectric interactions are more likely to occur in
bone
the probability of Compton scattering depends on the energy level of the incident x-ray photon
true
after a photoelectric interaction, the incident photons
loses all of its energy and no longer exists
classical interactions are also known as
thompson and coherent scattering
the x-ray photon being produced during classical scattering
travels in a different direction than the incoming photon
excessive absorption is the result of
using a kvp too low for the examination
the effect of classical scatter interactions on image quality
is minimal
secondary x-ray photons are the result of
Compton interactions and photoelectric interactions
pair production requires an x-ray photon with an energy of at least
1.02 MeV
true or false
the probability of a photoelectric interaction depends on the energy level of the incident x-ray photon
true
The greater the absorption of radiation
the greater the patient dose.
