Midterm Test Flashcards
What is the most effective method to reduce image blur due to pt movement?
Good Communication
Which of the following techniques will result in the highest pt dose?
Low kvp, high grid ratio
Which of the following describes grid ratio?
The height of the lead strips divided by the distance between them.
Which of the following will increase xray beam attenuation?
Increased tissue density & lower kvp
As mAs decreases, the quantity of radiation reaching the IR?
Decreases
Which interaction results in the most pt dose in diagnostic imaging?
Photoelectric effect
Which of the following interactions results in the production of fog?
Compton
For characteristic radiation, an orbital electron must be removed from which shell to produce a useful xray photon?
K Shell
How much total filtration is required for xray tubes that operate above 70kvp?
2.5mm Al
What mA is necessary to produce 24 mAs if you select 0.06 seconds?
400mA
What can the radiographer do to reduce the appearance of noise on a radiographic image
Increase mAs & decrease grid ratio
Which of the following materials is commonly used for beam filtration?
Aluminum
1Which of the following interactions between xray phtons & tissue results in the production of secondary xray photon?
Compton interaction
Why is PBL useful in radiography?
To reduce pt dose by limiting the size of the exposure to the size of the receptor.
A tech receives an exposure of40 mR at a distance of 6 feet from the source of exposure. What is the exposure if they were 3 feet from the source of the exposure?
160 mR
To keep pt dose to a minimum, the tech should use?
Higher kVp, lower mAs.
An xray beam passes through tissue and loses some of its energy. This is known as?
Attenuation
During a photoelectric interaction, the energy of the photoelectron ejected is = to?
Incident photon energy – binding energy.
If the SID Is doubled, what happens to the intensity of the xray beam?
Intensity decreases by a factor of 4.
What happens to the xray emission spectrum when the kvp is increased?
The amplitude increases and the spectrum shifts to the right.
Which of the following occurs when a projectile electron undergoes a characteristic interaction?
An inner shell electron is ionized.
Which interaction, within the diagnostic range, does not involve the removal of an orbital electron?
Classical scattering.
Given the following set of exposure factors (40” SID, 200mA, 0.05 seconds, 70kvp, 0.5” OID), which change would result in the greatest increase in magnification?
4” OID
All of the following are true about Compton scattered photons, except?
If the scattered photon strikes the IR, it will provide useful info.
Which factor listed results in images with a long scale of contrast?
Increased kVp
If the mAs is too low and the number of photons reaching the IR is too few, the image will display which of the following?
More noise
Which of the following is the term used to describe the blurring around the periphery of the image?
Penumbra
The energy of a scattered xray photon is?
less than the energy of the primary beam
Which of the following is a measure of beam quality?
Half value layer
Which of the following describes the production of xrays due to a collision between an incident electron and a k shell electron?
Characteristic interaction
Which of the following statements is true about xray interactions with matter?
Decreasing xray beam quality increases beam attenuation.
Which of the following describes automatic variable aperture collimation?
PBL
The xray beam that leaves the pt in the direction of the IR is often referred to as?
Remnant radiation and exit radiation
Which of the following affect size distortion?
SID & OID
Which of the following will result in the biggest increase in distortion on a radiographic image?
Increasing CR angle & decreasing SID?
Which of the following interactions in the diagnostic range involves the total absorption of the incident photon?
Photodisintegration
When using a wedge filter:
the thickest portion of the filter is placed over the thinnest part of the pt.
Which of the following help reduce the amount of scattered radiation reaching the IR?
Increased collimation
A thicker body part results in which of the following?
increased beam attenuation
Which of the following occurs if there is not enough tube filtration?
An increase in high energy photons & increased pt dose
An incident photon can be described as an xray photon that has:
not yet hit an object
Which of the following statements regarding radiographic grids is true?
If the height of the grid strips increases, & the space between them decreases, the grid will be more efficient.
A radiograph of an ankle is taken with the CR perpendicular to the IR but the ankle is not parallel to the IR. What type of distortion will be demonstrated on the image?
foreshortening
The ability to distinguish between adjacent similar tissues best describes?
contrast resolution
How much radiation can be attenuated by a high quality grid?
Up to 97%
Which of the following sets of exposure factors would create the highest radiographic beam quality?
80kVp, 2.5 mm Al filtration
When comparing low kVp techniques to high kVp techniques, which of the following is true?
Higher kVp results in fewer photon interactions & increased transmission.
What is the purpose of a compensating filter?
to replace a radiographic grid
Which of the following occurs when collimation is increased?
scatter radiation decreases & image contrast increases.
The electrostatic attraction between an incident electron & the nucleus of an atom will result in the production of which of the following?
Bremsstrahlung xray photon
Which of the following affects the amount of scatter radiation interacting with the IR, but does not affect the production of scatter radiation?
grid ratio
A photon of 10 MeV colliding with a nucleus of an atom will likely result in which of the following interactions?
photodisintegration
When you increase beam restriction, which of the following occurs?
pt dose decreases & image contrast increases
A pt has an external fixation device on their lower extremity. This results in a large OID. What can the radiographer do to minimize the resultant distortion on the image?
Increase SID
Which of the following factors will result in more xray beam transmission?
smaller body parts
As the exposure field size increases, pt dose ___, due to ___.
increases, increased scatter
How does filtration affect pt dose?
As filtration decreases, pt dose increases.
Which of the following circumstances would require the use of a grid?
12cm part thickness
Which of the following occurs when the volume of tissue irradiates is reduced?
decreased amount of scatter production
An xray photon looses part of its energy when it interacts with an outer shell electron in a pts tissue. This is known as?
attenuation
What is the relationship between mAs & pt dose?
Directly related
The photoelectric effect results in an increased dose to the __, and results in a ___contrast image.
pt, high
Grids are composed of lead strips & ?
aluminum interspace material
plastic fiber interspace material
A tech is going to perform a portable abdomen xray on an ICU pt. Which of the following grids would be the most appropriate choice to use?
6:1 parallel grid
The contrast on an image with a grid divided by the contrast on an image without a grid best describes which of the following?
contrast improvement
Which of the following will result in the greatest pt radiation dose?
Changing from a lower to higher ratio grid
Which interaction requires 1.02 MeV of energy?
pair production
Which of the following exposure factors will result in the greatest exposure to the IR?
0.04 secs, 800 mA
If collimation is reduced, the image contrast will ___ & the pt dose will____?
decrease, increase
Which of the following describes how much technique or pt dose increases with the use of a grid?
bucky factor
The amount of detail present in an image is known as?
spatial resolution
All of the following help to reduce the production of scatter radiation, EXCEPT?
increasing grid ratio
As the xray beam interacts with tissue some of the radiation will be absorbed in the tissue & some will be transmitted & strike the IR. This process is referred to as?
differential absorption
The purpose of filtration is?
to remove high energy xray photons
Which type of grid must be used at specific distances?
focused
