146 terms

Rad Image I Final

Which of the following terms could be defined as the instantaneous production of light caused by an interaction between a type of energy and some element or compound?
a. phosphorescence
b. afterglow
c. glowing
d. fluorescence
Erythema, an early sign of biological damage due to x-ray exposure is:
a. reddening of he skin
b. malignant tumor
c. chromosomal change
d. one of the most serious effects of x-ray exposure
Which of the following is correct description of the relationship between the wavelength and the frequency of the x-ray photon?
a. wavelength and frequency are directly proportional
b. wavelength and frequency are inversely related by the square root of lambda
c. frequency and wavelength are inversely related
d. wavelength and frequency have no relationship to each other
________ is a small, discrete bundle of energy
The speed of light:
a. 3 x 10^8 meters per second
b. 3 x 10^8 miles per second
c. 186,000 miles per second
d. a and c
True/False. X-rays are invisible
True/False X-rays carry a negative charge that causes ionization.
True/False X-ray photons travel at the speed of light in a vacuum.
True/False X-ray photons are capable of traveling around corners.
True/False Chemical changes may occur as a result of exposure to ionizing radiation.
The _____ is the portion of the x-ray tube that contains the filament.
a. cathode
b. anode
c. rotor
d. rotating disk
The positive side of the x-ray tube is:
a. anode
b. cathode
c. window
d. stream of electrons
What is the name of the exact area on the anode that is struck by the electron beam?
a. focal spot
b. focal point
c. target
d. any of the above
What is an acceptable level of leakage from the tube housing?
a. 100 mR/hr measured 6 ft away
b. 10 mR/hr measured 1 ft away
c. 1000 R/hr measured at a distance of 4 meters
d. 100 mR/hr measured at distance of 1 meter
________ is the boiling off of electrons from the filament when current is applied.
thermionic emission
mA is the measure of _____ that flows from the cathode to the anode.
a. filament current
b. tube current
c. space charge
d. thermionic emission
Increasing the kVp will do which of the following?
a. decrease the tube current
b. increase the speed of electrons
c. increase the penetrability of the beam
d. b and c
The filtration of the x-ray beam results in:
a. increased beam quantity
b. increased beam quality
c. lower average energy photons
d. b and c
The amt of filtration required to reduce the exposure of the beam to half of its original intensity is defined as:
a. wedge filtration
b. HVL
c. mAs compensator
d. mA linearity
_____ results in the process of the image formation, whereby the x-ray beam interacts with the anatomic tissue and a portion of the beam strikes the image receptor.
Differential absorption
______ is loss of some of the energy from the x-ray beam as it passes through the tissue being imaged
True/False. The photoelectric effect is dependent on both the energy of the x-ray photon and the composition of the anatomic tissue.
When the x-ray photon travels completely through the part, that activity is called:
a. acceleration
b. penetration
c. transmission
d. absorption
The xray beam that leaves the patient in the direction of the image receptor is often referred to as:
a. primary radiation
b. exit radiation
c. absorbed radiation
d. scattered radiation
Unwanted density on the radiograph due to scatter radiation is called:
a. latent
b. manifest
c. fog
d. backscatter
True/False More than 15% of the primary xray beam actually reaches the image reception
_____ image occurs first on the image receptor, and the _____ iamge occurs following proper image development/processing.
a. manifest, latent
b. invisible, latent
c. visible, manifest
d. latent, manifest
At higher kV, _____ photon interactions occur, resulting in _____ transmission
a. more, increased
b. more, less
c. fewer, increased
d. fewer, less
Imaging of the movement of internal structures is known as:
a. image intensification
b. digital imaging
c. photoelectric effect
d. fluoroscopy
The digital radiographic system that uses a cassette is:
a. DR
b CT
c CS
d CR
What effect does using a grid have on contrast?
a. Produce a longer scale of contrast
b. decrease contrast
c. increase contrast
d. have no effect on contrast
True/False For a given exposure technique, increasing part thickness decreases radiographic density.
If a person stands 12 ft from the source of exposure, receives an exposure of 16 R/min, and then moves 3 ft from the source of exposure, what would be the new exposure rate according to the inverse square law?
a. 256 R/min
b. 64 R/min
c. 1 R/min
d. 4 R/min
a; I1/I2 = (D2/D1)^2
If the first radiograph of a chest is done using 72" and 12 mAs and a second radiograph is done using 40 ", how much mAs should be used to maintain density?
a. 7 mAs
b. 2 mAs
c. 9 mAs
d 4 mAs
d; mAs1/mAs2=(D1/D2)^2
If a person stands 3 ft from the source of exposure, receives an exposure of 16 R/min and then moves to 6 ft from the source of exposure, what would the new exposure rate according to the inverse square law?
a. 4 R/min
b. 64 R/min
c. 256 R/min
d. 1 R/min
a; I1/I2=(D2/D1)^2
If the first radiograph of a foot is done using 4 mAs at 40" and a second radiograph is done using 50", how much mAs should be used to maintain density?
a. 12
b. 1
c. 2
d. 6
d; mAs1/mAs2=(D1/D2)^2
Considering the primary controller of radiographic density, which film has the greatest density?
a. 800 mA, .01 sec
b. 400 mA, 2 sec
c. 100 mA, .5 sec
d. 300 mA, 1 sec
In order to reduce patient exposure a _____ kVp and _____ mAs should be used when possible.
higher, lower
If mAs were fixed, which kVp would produce th greatest density?
a. 80
b. 90
c. 70
d. 100
What is the minimum change in mAs that would result in a visible change in radiographic density?
When imaging the thoracic spine, in order to take advantage of the anode heel effect the most superior portion of the patient's spine should be placed beneath:
a. the cathode end of the tube
b. either end; it doesnt matter
c. middle of the tube
d. anode end of the tube
For every ______ of part thickness, the radiographer should adjust the mAs by a factor by 2.
4-5 cm
A quality radiograph is dones using 10 mAs, 70 kVp, and 12:1 ratio grid. How much mAs is needed to produce an image with the same density when the grid is removed?
a. 50
b. 15
c. 2
d. 5
c; mAs1/mAs2=grid1/grid2
none = 1
5:1 = 2
6:1 = 3
8:1 = 4
12:1 = 5
16:1 = 6
True/False kV does not affect radiographic density until adequate penetration is reached.
Density is a ______ property of radiographic image.
Contrast is a _____ property of radiographic image
Density is:
measuring of the overall blackening of the radiographic image
If kVp decreased 15% and no change to mAs then:
density would decrease contrast would increase
What would be appropriate change in mAs if kVp decrease by 15% and density needed to be maintained?
twice the mAs
Assuming all exposure factors remain unchanged what is result of changing to an IR with higher relative speed?
Density increases
Assuming all produce appropriate density images, which of hte following would be best exposure technique choice when perform cxr on infant?
use 40 ms exposure time; shortest exposure time
When radiograph need to repeat bc its too dark, minimum change in mAs needed is:
reduce mAs by 50%
All factor same, patient w/which body habitus would require highest exposure?
Generally what added pathologic condition require?
increase kVp
Which of the following changes will result in increased density w/ no change in contrast?
decrease SID
Which is destructive pathology?
Barium sulfate is contrast, its necessary to:
increase kVp
What are the four primary exposure factors?
kVp, mAs, time and SID
An increase in mAs causes _______ in beam quality and _____ in beam quantity
no change, increase
if mAs is increased from 20 mAs to 40 mAs, the patient does will ______.
Beam penetrability is increased if _____ is/are increased.
a. mAs
b. SID
c. kVp
d. all above
A ____% increase in kVp has the same effect on optical density as doubling the mAs.
A radiograph taken using 75 kVp @ 20 mAs. Which change in technique would increase contrast but maintain the same density?
a. 85 kVp @ 10 mAs
b. 85 kVp @ 40 mAs
c. 65 kVp @ 20 mAs
d. 65 kVp @ 40 mAs
d, decrease kVp = increase contrast
At least a ____% change in mAs is necessary to produce a visible change in optical density.
A radiograph taken using 65 kVp @ 10 mAs is too light. Which technique would double the optical density while produce a wider scale of contrast?
a. 75 @ 10
b. 75 @ 20
c. 55 @ 10
d. 55 @ 20
Which technique would give the highest patient dose?
a. 90 kVp/200 mA @ .02 sec
b. 87 kVp/400 mA @ .02 sec
c. 74 kVp/400 mA @ .04 sec
d. 65 kVp/300 mA @ .1 sec
Added filtration has the effect of ______ beam quality and ______ patient dose.
increasing, reducing
Which medical condition may require a lower technique?
a. atelectasis
b. emphysema
c. pneumonia
d. pleural effusion
When only the optical density needs to be changed, only the ____ should be adjusted.
a. mAs
b, kVp
c. SID
d. filtration
With aec the exposure is terminated when the optimum ______ is reached.
a. optical density
b. time
c. mAs
d. kVp
An image with low contrast appears:
a. black and white
b. very gray
c. very dark
d. very light
A radiograph with few densities but great differences among them is said to have:
a. high contrast
b. low contrast
c. long-scale contrast
d. medium-scale contrast
What is the primary controller of image contrast?
a. kvp
b. ma
c. second
d. none
Reducing the area of exposure (increasing collimation) _____ image contrast.
Abdomen image is done using 66 kVp and 40 mAs. Image desnity is appropriate but the image has too high (short scale) contrast. Which of these exposure factors would be the best change to make?
a. 56 @ 60
b. 66 @ 20
c. 76 @ 40
d. 76 @ 20
Image-forming xray include those which have been ____.
a. transmitted without interaction
b. scattered through compton scatter
c. absorbed through photoelectric interaction
d. b and a
Compton scatter contributes to ______.
image noise
Decreasing the kVp will increase _____.
patient dose
Photoelectric interaction increase when ______ is decreased
Scattered radiation increases as _______ increases.
a. photoelectric absorption
b. field size
c. filtration
d. contrast
The xrays that are transmitted through the patient w/o interaction contribute to ______.
a. useful information
b. film fog
c. image noise
d. all above
The most commonly used beam restricting device is the ______
a. extension cone
b. variable collimator
c. aperture diaphragm
d. compression device
Lower kVp _____ patient dose and _______ image contrast.
increases, increases
The use of ____ improves contrast and reduces patient dose.
a. collimation
b. high kVp
c. low kVp
d. less filtration
_____ is define as the ability to image two separate objects and visually detect one from the other.
a. contrast
b. resolution
c. detail
d. noise
The technologist primarily controls radiographic contrast by varying the ______.
a. image receptor
b. kV
c. voltage ripple
d. mA
Optical density is primarily controlled by changing the _____.
Which kVp would result most scatter?
highest kVp
Approximately ____% xray beam incident on patient is transmitted through patient w/o interaction to become part image from beam.
Xray interaction contribute to clear part image:
photoelectric interaction
3 primary factor influencing intensity of scatter in image forming beam:
kVp, field size, patient thickness
Contrast resolution is improve by ____
tight collimation, lower kVp, patient compression
use compression device will increase
PBL assure that ray beam is collimate ______
image receptor size
How can you improve image contrast w/ heavy pt w/o increase pt dose?
use tight collimation
Which grid design is manufactured to match divergence xray beam
focused grid
True/False Use grid device reduce amt scatter radiation produce
Cxr norm 72" use 2.5 mAs what mAs @ 60"?
True/False Every photon penetrate equally, still have scale contrast.
Number lead strip per inch in grid is measured as
grid frequency
Low kVp technique use and light image result what happen to xr photon in beam?
most absorbed
What occur when scatter strike film
radiographic contrast decreases
9x9 open to 14x17, no change, what density?
Height lead strip relative to distance btwn lead strip measure of?
grid ratio
What determine # boil off of electron
What grid ratio for kVp of 100?
Waht influence amt scatter strike IR not production scatter?
increase grid ratio
Which kVp setting will provide the most kinetic energy to filament electrons?
highest kVp
Which kVp is capable of producing the lowest contrast?
highest kVp
Why is scatter radiation exposure undesireable?
Decrease contrast
What is the xray absorbing material in grid?
Collimation acts to reduce scatter and its resultant image fog primarily by which of the following?
limiting area of exposure
A positive contrast media will have what effect on radiographic contrast?
Change in kVp affect:
a. optical density
b. image contrast
c. image noise
d. all above
A radiograph with long scale of contrast will have ____ latitude and ____ contrast.
wide, low
Radiograph ________ is random fluctuation in the optical density of a radiograph.
Higher speed image receptors generally produce images with _______.
a. better resolution
b. increased noise
c. higher contrast
d. improved detail
The slope of the ____ portion of the characteristic curve shows the film contrast.
a. base
b. shoulder
c. toe
d. straight line
In general radiography the useful optical densities lie between ___ and ___
.25 and 2.5
What is the formula for optical density?
OD= log10(I0/It)
If 10% of view box light is transmitted through an area of film, what is the optical density in that area?
The densities above 2.5 on a film are represented in the ______ portion of the characteristic curve.
An image receptor with ____ can be used over a greater range of exposures.
wide latitude
Subject contrast is affected by
patient thickness
Which of these body parts has the highest subj contrast?
a. abdomen
b. skull
c. chest
d. pelvis
An artifact can be _______.
a. an object that is not part of the radiographed anatomy
b. patient motion
c. an improper grid or warped cassette
d. any of above
____ is example of an exposure artifact.
foreign object
A static mark artifact is created during ____ of the film.
Grid-cassette htat is improperly positioned can cause a ____ artifact
grid cut off
What can cause image blur on the finished radiograph?
patient motion
Kink marks are caused by ______.
bending of film
What is the purpose of the technique chart?
a. decrease patient exposure by always using the highest kVp
b. to ensure consistent image quality
c. to reduce repeats due to technique error and in turn reduce patient exposure
d. b and c
A technique chart should be est for:
each tube
Which of the following is/are true regarding development of an effective technique chart?
a. processor must be consistent
b. equipment must be calibrated
c. equipment must be from same manufacturer
d. a and b
What are calipers used for?
measure the part
Which of the following is NOT required to be part of a standardized technique chart?
a. SID
b. OID
c. mA
d. kVp
What is the appropriate change in kVp when using a variable kVp/fixed mAs for a 1 cm change in tissue thickness?
2 kVp
What kind of chart uses a kVp value that is high enough to adequately penetrate the part but doesnt diminish radiographic contrast?
fixed kVp
When using the fixed kVp/variable mAs, if part thickness increases by 5 cm what needs to happen to the mAs?
True/False Technique charts are still needed when using AEC
True/False Technique chart will provide info as to how to recognize and compensate for additive pathology.
Departmental standard such as the SID or whether an exam is done table top or bucky should be determined.
prior to the development of technique chart
Accurate patient measurement is most critical for the:
variable kVp/ fixed mAs
Generally speaking patient dose will decrease with the:
fixed kVp/variable mAs
True/False Optimal kVp values for each anatomic area have been established.
Patient measuring 26 cm requires 25 mAs @ 75 kVp based on fixed kVp/variable mAs technique chart. What technique should be used for the next patient who measures 34 cm?
100 mAs @ 75 kVp