Image Acquisition and Evaluation Flashcards
Geometric blur can be evaluated using all the ff devices except
a. star pattern
b. slit camera
c. penetrometer
d. pinhole camera
Penetrometer
What pixel size has a 512 x 512 matrix with a 20 cm field of view (FOV)?
0.40 mm/pixel
In electronic imaging, as digital image matrix size increases
- pixel size decreases
- resolution decreases
- pixel depth decreases
1 only
An increase in added filtration will result in
- an increase in maximum energy of the xray beam
- a decrease in xray intensity
- an increase in effective energy of the xray beam
2 and 3 only
SID affects recorded detail in which of the ff ways?
Recorded detail is directly related to SID
Grid interspace material can be made of
- carbon fiber
- aluminum
- plastic fiber
2 and 3 only
The exposure factors used for a particular nongrid xray image were 300 mA, 4 ms, and 90 kV. Another image, using an 8:1 grid, is requested. Which of the ff groups of factors is most appropriate?
400 mA, 12ms, 19kv
An increase in kilovoltage will have which of the ff effects?
- More scattered radiation will be produced.
- The exposure rate will increase.
- Radiographic contrast will increase.
10
The xray tube used in CT must be capable of
- high-speed rotation
- short pulsed exposures
- withstanding millions of heat units
all
Decreasing field size from 14x17 in to 8x10 in, with no other changes will
decrease the amount of scaterred radiation generated within the part
Which of the ff groups of exposure factors will produce the most radiographic density?
400 mA, 70ms
The component of a CR image plate (IP) that records the radiologic image is the
photostimulable phospor
An xray image of the ankle was made at 40 SID, 200 mA, 50 ms, 70 kV, 0.6 mm focal spot, and minimal OID. Which of the ff modifications would result in the greatest increase in magnification?
4-in OID
A lateral radiograph of the cervical spine was made at 40 in using 300 mA and 0.03 second exposure. If it is desired to increase the distance to 72 in, what should be the new milliampere (mA) setting, all other factors remaining constant?
300
Which of the ff statements regarding dual xray absorptiometry is (are) true?
- Radiation dose is low.
- Only low-energy photons are used.
- Photon attenuation by bone is calculated.
1 and 3 only
The luminescent light emitted by the PSP is transformed into the image seen on the CRT by the
ADC
Which of the ff is/are true when comparing film-screen imaging to CR imaging?
- CR DQE is better than film-screen DQE.
- CR has a wider exposure range than film-screen.
- CR has better spatial resolution than film-screen.
1 and 2 only
The term windowing describes the practice of
changing the image brightness and/or contrast scale
Foreshortening can be caused by
the radiographic object being placed at an angle to the IR
Acceptable method(s) of minimizing motion unsharpness is (are)
- suspended respiration
- short exposure time
- patient instruction
all
Using fixed milliampere-seconds and variable kilovoltage technical factors, each centimeter increase in patient thickness requires what adjustment in kilovoltage?
Increase 2 kV
Unopened boxes of radiographic film should be stored away from radiation
in the vertical position
If a duration of 0.05 second was selected for a particular exposure, what milliamperage would be necessary to produce 30 mAs?
600
Factors that contribute to film fog include
- the age of the film
- excessive exposure to safelight
- processor chemistry
all
Xray photon energy is inversely related to
- photon wavelength
- applied miiliamperes (mA)
- applied kilovoltage (kV)
1 only
Characteristics of DR imaging include
- solid state detector receptor plates
- a direct-capture imaging system
- immediate image display
all
Compared with a low-ratio grid, a high-ratio grid will
- allow more centering latitude
- absorb more scattered radiation
- absorb more primary radiation
2 and 3 only
Subject/object unsharpness can result from all of the ff except when
anatomic object(s) of interest is/are in the path of CR
To be suitable for use in an image intensifier’s input screen, a phosphor should have which of the following characteristics?
all
Resolution in CR increases as
- laser beam size decreases
- monitor matrix size decreases
- PSP crystal size decreases
1 and 3 only
Pathologic or abnormal conditions that would require an increase in exposure factors include all of the following except
a. atelectasis
2. pneumoperitoneum
c. Paget Disease
d. CHF
pneumoperitoneum
In radiography of a large abdomen, which of the ff is (are) effective way(s) to minimize the amount of scattered radiation reaching the imgae receptor (IR)?
- Use of close collimation
- Use of low mAs
- Use of a low-ratio grid
1 only
Which of the ff factors contribute (s) to the efficient performance of a grid?
1. Grid ratio
2, Number of lead strips per inch
3. Amount of scatter transmitted through the grid
all
All of the ff affect the exposure rate of the primary beam except
a. mA
b. kV
c. distance
d. field size
field size
Factors that determine the production of scattered radiation include
- field size
- beam restriction
- kilovoltage
all
Image contrast is a result of
- differential tissue absorption
- atomic number of tissue being traversed
- proper regulation of milliampere-seconds
1 and 2 only
A 5-in. object to be radiographed at a 44-in SID lies 6 in. from the IR. What will be the image width?
5.7 in.
In comparison with 60 kV, 80 kV will
- permit greater exposure latitude
- produce more scatter radiaiton
- produce shorter-scale contrast
1 and 2 only
The term pixel is associated with all of the ff except
a. two dimensional
b. picture element
c. measured in xy direction
d. how much of the part is included in the matrix
d
Misalignment of the tube-part-IR relationship results in
two dimentional
Causes of grid cutoff, when using focused reciprocating grids, include the ff?
- Inadequate SID
- Xray tube off-center with the long axis of the lead strips
- Angling the beam in the direction of the lead strips
1 only
Using a short (25–30 in.) SID with a large (14 × 17 in.) IR is likely to
Increase the anode heel effect
Which of the following groups of factors would produce the least
radiographic density?
(A) 400 mA, 0.010 second, 94 kV, 100-speed screens
(B) 500 mA, 0.008 second, 94 kV, 200-speed screens
(C) 200 mA, 0.040 second, 94 kV, 50-speed screens
(D) 100 mA, 0.020 second, 80 kV, 200-speed screens
100 mA, 0.020 second, 80 kV, 200-speed screens
Chemical fog may be attributed to
- excessive developer temperature
- oxidized developer
- excessive replenishment
1,2 and 3
Greater latitude is available to the radiographer in which of the following circumstances? 1. Using high-kV technical factors 2. Using a low-ratio grid 3. Using low-kV technical factors
1 and 2 only
The differences between CR and DR include
- CR uses IPs.
- CR has higher DQE and lower patient dose.
- CR images are displayed immediately
1 only
The term voxel is associated with all of the following except (A) bit depth (B) volume element (C) measured in Z direction (D) field of view
Field of view
Using a 48-in. SID, how much OID must be introduced to magnify an object
two times?
24 inch OID
A particular radiograph was produced using 12 mAs and 85 kV with a 16:1
ratio grid. The radiograph is to be repeated using an 8:1 ratio grid. What
should be the new milliampere-seconds value?
8
The main difference between direct capture and indirect capture DR is that
Direct capture/convertion has no scontillator
The direction of electron travel in the x-ray tube is
Cathode to anode
Which of the following technical changes would best serve to remedy the
effect of very dissimilar tissue densities?
(A) Use of a small focal spot
(B) Use of a high-ratio grid
(C) High-kilovoltage exposure factors
(D) High milliampere-seconds exposure factors
High-kilovoltage exposure factors
For the same FOV, spatial resolution will be improved using
A large matrix
Which of the following are methods of limiting the production of scattered
radiation?
1. Using moderate ratio grids
2. Using the prone position for abdominal examinations
3. Restricting the field size to the smallest practical size
2 and 3 only
The absorption of useful radiation by a grid is called
Grid cut off
Types of shape distortion include
- magnification
- elongation
- foreshortening
2 and 3 only
For the same FOV, as the matrix size increases
- spatial resolution increases
- image quality increases
- pixel size decreases
1,2 and 3
During CR imaging, the latent image present on the PSP is changed to a
computerized image by the
ADC
All the following are related to recorded detail except 464 (A) milliamperage (B) focal-spot size (C) SID (D) OID
Milliamperage
A satisfactory radiograph was made using a 36-in. SID, 12 mAs, and a 12:1
grid. If the examination will be repeated at a distance of 42 in. and using a
5:1 grid, what should be the new milliampere-seconds value to maintain the
original density?
6.5
Of the following groups of exposure factors, which will produce the most radiographic density?
200 mA, 60ms, 36-in SID
Which of the following groups of exposure factors will produce the shortest
scale of contrast?
(A) 200 mA, 0.08 second, 95 kV, 12:1 grid
(B) 500 mA, 0.03 second, 70 kV, 8:1 grid
(C) 300 mA, 0.05 second, 95 kV, 8:1 grid
(D) 600 mA, 1/40 seconds, 70 kV, 6:1 grid
500 mA, 0.03 second, 70 kV, 8:1 grid
Pathologic or abnormal conditions that would require a decrease in exposure
factors include all of the following except
465
(A) osteoporosis
(B) osteomalacia
(C) emphysema
(D) pneumonia
pneumonia
Which of the following is likely to contribute to the radiographic contrast present on the finished radiograph? 1. Atomic number of tissues radiographed 2. Any pathologic processes 3. Degree of muscle development
1,2 and 3
Which of the following factors influence(s) the production of scattered radiation? 1. Kilovoltage level 2. Tissue density 3. Size of field
1,2, and 3
A 15% decrease in kilovoltage accompanied by a 50% increase in
milliampere-seconds will result in a(n)
Shorter scale contrast
Which of the following factors impact(s) recorded detail?
- Focal-spot size
- Subject motion
- SOD
1,2 and 3
Which of the following is (are) tested as part of a quality assurance (QA) program? 1. Beam alignment 2. Reproducibility 3. Linearity
1,2 and 3
Focal-spot blur is greatest
Toward the cathode end of the xray tube
How are mAs and patient dose related?
Directly proportional
Image plate front material can be made of which of the following?
- Carbon fiber
- Magnesium
- Lead
1 and 2 only
Which of the following pathologic conditions would require a decrease in exposure factors? (A) Congestive heart failure (B) Pneumonia (C) Emphysema (D) Pleural effusion
Emphysema
If a radiograph exposed using a 12:1 ratio grid exhibits increased
brightness/loss of density at its lateral edges, it is probably because the
SID was too great
. Practice(s) that enable the radiographer to reduce the exposure time required for a particular image include 1. use of a higher milliamperage 2. use of a higher kilovoltage 3. use of a higher ratio grid
1 and 2 only
If 400 mA, 10 ms, and 90 kV were used for a particular exposure using threephase, 12-pulse equipment, which of the following exposure changes would
be most appropriate for use on single-phase equipment to produce a similar
image?
Use 0.2 second
Which of the following materials may be used as grid interspace material?
- Lead
- Plastic
- Aluminum
2 and 3 only
Which of the following can impact the visibility of the anode heel effect?
- SID
- IR size
- Focal spot size
1 and 2 only
An increase in the kilovoltage applied to the x-ray tube increases the
- x-ray wavelength
- exposure rate
- patient absorption
2 only
Which of the following statements about histograms is/are true?
- A histogram illustrates pixel value distribution.
- There is a default histogram for each/different body parts.
- A histogram is representative of the image grayscale.
1,2 and 3
Which of the following is the correct order of radiographic film processing? 471 (A) Developer, wash, fixer, dry (B) Fixer, wash, developer, dry (C) Developer, fixer, wash, dry (D) Fixer, developer, wash, dry
Developer, fixer, wash, dry
If the radiographer is unable to achieve a short OID because of the structure of
the body part or patient condition, which of the following adjustments can be
made to minimize magnification distortion?
A longer SID should be used
The reduction in x-ray photon intensity as the photon passes through material
is termed
Attenuation
Exposure rate will decrease with an increase in
- SID
- kilovoltage
- focal spot size
1 only
Which of the following pathologic conditions probably will require a decrease in exposure factors?
(A) Osteomyelitis
(B) Osteoporosis
(C) Osteosclerosis
(D) Osteochondritis
Osteoporosis
Diagnostic x-rays are generally associated with
High frequency, ahort wavelength
A film/screen image exhibiting insufficient density might be attributed to
- inadequate kilovoltage
- inadequate SID
- grid cutoff
1 and 3 only
If a lateral projection of the chest is being performed on an asthenic patient
and the outer photocells are selected, what is likely to be the outcome?
Decrease density
Which of the following devices is used to overcome severe variation in patient
anatomy or tissue density, providing more uniform radiographic density?
(A) Compensating filter
(B) Grid
(C) Collimator
(D) Added filtration
Compensating filter
What are the effects of scattered radiation on a radiographic image?
- It produces fog.
- It increases contrast.
- It increases grid cutoff
1 only
Which of the following groups of exposure factors would be most appropriate to control involuntary motion? (A) 400 mA, 0.03 second (B) 200 mA, 0.06 second (C) 600 mA, 0.02 second (D) 100 mA, 0.12 second
600 mA, 0.02 second
Methods that help to reduce the production of scattered radiation include using
- compression
- beam restriction
- a grid
1 and 2 only
The function(s) of the developer in film processing is (are) to
- remove the unexposed silver bromide crystals
- change the exposed silver bromide crystals to black metallic silver
- harden the emulsion
2 only
. Although the stated focal spot size is measured directly under the actual focal
spot, focal spot size actually varies along the length of the x-ray beam. At
which portion of the x-ray beam is the effective focal spot the largest?
At the cathode end
Which of the following affect(s) both the quantity and the quality of the primary beam? 1. Half-value layer (HVL) 2. Kilovoltage (kV) 3. Milliamperage (mA)
1 and 2 only
The intensity of ionizing radiation decreases as
Distance from the source of radiation increases
Which of the following would be useful for an examination of a patient suffering from Parkinson’s disease? 1. Short exposure time 2. Decreased SID 3. Compensating filtration
Short exposure time
Underexposure of a radiograph can be caused by all the following except insufficient (A) milliamperage (mA) (B) exposure time (C) Kilovoltage (D) SID
SID
Potential digital image postprocessing tasks include
- PACS
- annotation
- inversion/reversa
2 and 3 only
An anteroposterior (AP) projection of the femur was made using 300 mA, 0.03 second, 76 kV, 40-in. SID, 1.2-mm focal spot, and a 400-speed film–screen system. With all other factors remaining constant, which of the following exposure times would be required to maintain radiographic density/brightness at a 44-in. SID using 500 mA?
22 ms
An AP radiograph of the femur was made using 300 mA, 30 ms, 76 kV, 40-in.
SID, and 1.2-mm focal spot. With all other factors remaining constant, which
of the following exposure times would be required to maintain
brightness/density using 87 kV and the addition of a 12:1 grid?
75 ms
HVLis affected by the amount of
- kVp
- beam filtration
- tissue density
1 and 2 only
In a posteroanterior (PA) projection of the chest being used for cardiac
evaluation, the heart measures 14.7 cm between its widest points. If the
magnification factor is known to be 1.2, what is the actual diameter of the
heart?
12.25 cm
Bone densitometry is often performed to
- measure degree of bone (de) mineralization
- evaluate the results of osteoporosis treatment/therapy
- evaluate the condition of soft tissue adjacent to bone
1 and 2 only
The differences between CR and DR include
- DR images are displayed immediately.
- DR has higher DQE and lower patient dose.
- DR uses IPs.
1 and 2 only
The process of “windowing” of digital images determines the image
Contrast
What is the purpose of the thin layer of lead that is often located in the rear
portion of an IP?
To increase speed
The purpose of the electroconductive layer of a CR PSP plate is to
Facilitate transportation through the scanner/reader
Which of the following combinations is most likely to be associated with
quantum mottle?
Decrease milliampere seconds, increase kilovoltage
What pixel size has a 2,048 × 2,048 matrix with a 60-cm FOV?
0.3 mm
Which of the following possesses the widest dynamic range? (A) Film/screen imaging (B) Beam restriction (C) AEC (D) CR
CR
Which of the following matrix sizes is most likely to produce the best image
resolution?
126
Factors that determine recorded detail in digital imaging include
- part motion
- geometric factors
- spatial resolution
1,2 and 3
Examples of health care informatics include
- HIS
- RIS
- PACS
1,2 and 3
The exposure factors of 400 mA, 17 ms, and 82 kV produce a milliampereseconds value of
6.8
All the following statements regarding CR IPs are true except
(A) IPs do not contain radiographic film.
(B) IPs use no intensifying screens.
(C) IPs must exclude all white light.
(D) IPs function to protect the PSP
& 131
The radiographic accessory used to measure the thickness of body parts in
order to determine optimal selection of exposure factors is the
Caliper
The x-ray image seen on the computer display monitor is a (an)
Analog image
A focal-spot size of 0.3 mm or smaller is essential for
Magnification radiography
For which of the following examinations can the anode heel effect be an important consideration? 1. Lateral thoracic spine 2. AP femur 3. Right anterior oblique (RAO) sternum
1 and 2 only
All the following have an impact on radiographic contrast except (A) photon energy (B) grid ratio (C) OID (D) focal-spot size
Focal spot size
A radiograph made with a parallel grid demonstrates decreased density on its
lateral edges. This is most likely due to
Decrease SID
A particular milliampere-seconds value, regardless of the combination of
milliamperes and time, will reproduce the same radiographic density. This is
a statement of the
Reciprocity Law
OID is related to recorded detail in which of the following ways?
(A) Radiographic detail is directly related to OID.
(B) Radiographic detail is inversely related to OID.
(C) As OID increases, so does radiographic detail.
(D) OID is unrelated to radiographic detail
Radiographic detail is inversely related to OID.
If 300 mA has been selected for a particular exposure, what exposure time
would be required to produce 6 mAs?
20 ms
In digital imaging, as DELsize decreases
Spatial resolution increases
An increase in kilovoltage will serve to
Prodeuce a longer scale contrast
The functions of automatic beam limitation devices include
- reducing the production of scattered radiation
- increasing the absorption of scattered radiation
- changing the quality of the x-ray beam
1 only
Recorded detail/resolution is inversely related to
- SID
- OID
- part motion
2 and 3 only
Of the following groups of exposure factors, which will produce the shortest scale of radiographic contrast? (A) 500 mA, 0.040 second, 70 kV (B) 100 mA, 0.100 second, 80 kV (C) 200 mA, 0.025 second, 92 kV (D) 700 mA, 0.014 second, 80 kV
500 mA, 0.040 second, 70 kV
Magnification fluoroscopy is accomplished by
- moving the image intensifier focal point further from the output phosphor
- selecting a smaller portion of the input phosphor
- decreasing the voltage to the electrostatic lenses
1 and 2 only
Of the following groups of technical factors, which will produce the greatest
radiographic density?
10 mAs, 74kV, 36 SID
Which of the following requires two exposures to evaluate focal-spot accuracy? (A) Pinhole camera (B) Slit camera (C) Star pattern (D) Bar pattern
Slit camera
Focusing distance is associated with which of the following? (A) Computed tomography (B) Chest radiography (C) Magnification radiography (D) Grids
Grids
The processing algorithm represents the
Anatomical part and projection
. The relationship between the height of a grid’s lead strips and the distance
between them is referred to as grid
ratio
. Because of the anode heel effect, the intensity of the x-ray beam is greatest
along the
cathode end of the beam
Characteristics of high-ratio focused grids, compared with lower-ratio grids,
include which of the following?
1. They allow more positioning latitude.
2. They are more efficient in collecting SR.
3. They absorb more of the useful beam.
2 and 3 only
Factors that can affect histogram appearance include
- beam restriction
- centering errors
- incorrect SID
1, 2, and 3
Changes in milliampere-seconds can affect all the following except (A) quantity of x-ray photons produced (B) exposure rate (C) optical density (D) recorded detail
recorded detail
Low-kilovoltage exposure factors usually are indicated for radiographic examinations using 1. water-soluble, iodinated media 2. a negative contrast agent 3. barium sulfate
1 and 2 only
Which of the following examinations might require the use of 70 kV?
- AP abdomen
- Chest radiograph
- Barium-filled stomach
1 only
Which of the following is/are associated with magnification fluoroscopy?
- Increased mA
- Smaller portion of the input phosphor is used.
- Image intensifier focal point moves closer to the output phosphor.
1 and 2 only
A lateral projection of the lumbar spine was made using 200 mA, 1-second
exposure, and 90 kV. If the exposure factors were changed to 200 mA, 0.5
second, and 104 kV, there would be an obvious change in which of the
following?
1. Radiographic density
2. Scale of radiographic contrast
3. Distortion
2 only
A decrease in kilovoltage will result in
a decrease in optical density
Brightness and contrast resolution in digital imaging can be influenced by
- window level (WL)
- window width (WW)
- look-up table (LUT)
1, 2, and 3
What feature is used to display RIS information on current patients?
Modality work list
A decrease from 200 to 100 mA will result in a decrease in which of the following? 496 1. Wavelength 2. Exposure rate 3. Beam intensity
2 and 3 only
The effect described as dif erential absorption is
- responsible for radiographic contrast
- a result of attenuating characteristics of tissue
- minimized by the use of a high peak kilovoltage
1, 2, and 3
A satisfactory radiograph of the abdomen was made at a 38-in. SID using 400
mA, 60-ms exposure, and 80 kV. If the distance is changed to 42 in., what
new exposure time would be required?
73 ms
Which of the following is (are) associated with subject contrast?
- Patient thickness
- Tissue density
- Kilovoltage
1, 2, and 3
Typical patient demographic and examination information include(s)
- type of examination
- accession number
- date and time of examination
1, 2, 3
For which of the following examinations might the use of a grid not be
necessary in an adult patient?
Knee
The quantity of scattered radiation reaching the IR can be reduced through the use of 1. a fast imaging system 2. an air gap 3. a stationary grid
2 and 3 only
Why is a very short exposure time essential in chest radiography?
To minimize involuntary motion
Beam attenuation characteristics, or density values, in CT are expressed as
- Hounsfield units
- CT numbers
- heat units
1 only
An exposure was made at a 36-in. SID using 300 mA, a 30-ms exposure, and
80 kV and an 8:1 grid. It is desired to repeat the radiograph using a 40-in.
SID and 70 kV. With all other factors remaining constant, what new exposure
time will be required?
1 and 2 only
Which of the following is (are) characteristic(s) of a 5:1 grid?
- It allows some positioning latitude.
- It is used with high-kilovoltage exposures.
- It absorbs a high percentage of scattered radiation.
0.07 second
How is SID related to exposure rate and image density?
- It allows some positioning latitude.
- It is used with high-kilovoltage exposures.
- It absorbs a high percentage of scattered radiation.
1 only
An x-ray exposure of a particular part is made and restricted to a 14 × 17 in. field size. The same exposure is repeated, but the x-ray beam is restricted to
a 4 × 4 in. field. Compared with the first image, the second image will
demonstrate
1. more contrast
2. higher contrast
3. more density
As SID increases, exposure rate decreases and image density decreases.
In digital imaging, TFT DELsize is related to (A) contrast (B) brightness (C) spatial resolution (D) plate size
spatial resolution
Which of the following pathologic conditions would require an increase in exposure factors? (A) Pneumoperitoneum (B) Obstructed bowel (C) Renal colic (D) Ascites
Ascites
Factors that determine recorded detail in digital imaging include
- focal spot size
- SID
- DEL size
1, 2, and 3
The photostimulable phosphor (PSP) plates used in CR are constructed in layers that include 1. light shield layer 2. support layer 3. electroconductive layer
1, 2, and 3
A QA program serves to
- keep patient dose to a minimum
- keep radiographic quality consistent
- ensure equipment efficiency
1, 2, and 3
The purpose of the electroconductive layer of a CR PSP plate is to
facilitate transportation through the scanner/reader
Any images obtained using dual x-ray absorptiometry (DXA) bone
densitometry
1. are used to evaluate accuracy of the region of interest (ROI)
2. are used as evaluation for various bone/joint disorders
3. reflect the similar attenuation properties of soft tissue and bone
1 only
Foreshortening of an anatomic structure means that
it is projected on the IR smaller than its actual size
To produce a just perceptible increase in radiographic density, the radiographer must increase the
mAs by 30%
A radiograph made using 300 mA, 0.1 second, and 75 kV exhibits motion unsharpness but otherwise satisfactory technical quality. The radiograph will
be repeated using a shorter exposure time. Using 86 kV and 400 mA, what
should be the new exposure time?
37 ms
X-ray tubes used in CT differ from those used in x-ray, in that CT x-ray tubes
must
505
1. have a very high short-exposure rating
2. be capable of tolerating several million heat units
3. have a small focal spot for optimal resolution
1, 2, and 3
Exposure-type artifacts include
- double exposure
- motion
- image fading
2 and 3 only
When involuntary motion must be considered, the exposure time may be cut in
half if the kilovoltage is
increased by 15%
Which of the following groups of exposure factors would be most effective in
eliminating prominent pulmonary vascular markings in the RAO position of
the sternum?
(A) 500 mA, 1/30 s, 70 kV
(B) 200 mA, 0.04 second, 80 kV
(C) 300 mA, 1/10 s, 80 kV
(D) 25 mA, 7/10 s, 70 kV
200 mA, 0.04 second, 80 kV
An exposure was made of a part using 300 mA and 0.06 second with a 200- speed film–screen combination. An additional radiograph is requested using a 400-speed system to reduce motion unsharpness. Using 400 mA, all other
factors remaining constant, what should be the new exposure time?
5 ms
HVLis affected by the amount of
- kVp
- beam filtration
- tissue density
200
The attenuation of x-ray photons is not influenced by
- pathology
- structure atomic number
- photon quantity
3 only
If, upon QC testing, the HVLof the x-ray beam produced by a particular x-ray
tube increases, it is an indication of
1. vaporized tungsten deposited on the inner surface of the glass envelope
2. an increase in the kilovoltage being produced by the tube
3. a decrease in the kilovoltage being produced by the tube
1 and 2 only
A compensating filter is used to
even out widely differing tissue densities
Boxes of film stored in too warm an area may be subject to
film fog
Which of the following will influence recorded detail?
- Dynamic range
- Part motion
- Focal spot
2 and 3 only
Which interaction is responsible for producing the most x-ray photons at the xray tube target?
Bremsstrahlung
Which of the following terms is used to describe unsharp edges of tiny
radiographic details?
Blur
Which of the following is (are) classified as rare earth phosphors?
- Lanthanum oxybromide
- Gadolinium oxysulfide
- Cesium iodide
1 and 2 only
As grid ratio is decreased,
the scale of contrast becomes longer
X-ray film emulsion is most sensitive to safelight fog
after exposure
Which of the following focal-spot sizes should be employed for magnification radiography? (A) 0.2 mm (B) 0.6 mm (C) 1.2 mm (D) 2.0 mm
0.2 mm
If a 6-in. OID is introduced during a particular radiographic examination, what
change in SID will be necessary to overcome objectionable magnification?
The SID must be increased by 42 in..
. If a particular grid has lead strips 0.40 mm thick, 4.0 mm high, and 0.25 mm
apart, what is its grid ratio?
16:1
The line-focus principle expresses the relationship between
the actual and the effective focal spot
Which of the following has the greatest effect on radiographic density/brightness? (A) Aluminum filtration (B) Kilovoltage (C) SID (D) Scattered radiation
SID
Shape distortion is influenced by the relationship between the
- x-ray tube and the part to be imaged
- part to be imaged and the IR
- IR and the x-ray tube
1, 2, and 3
IRs frequently have a rear lead-foil layer that functions to
absorb backscatter
The continued emission of light by a phosphor after the activating source has
ceased is termed
phosphorescence
How often are radiographic equipment collimators required to be evaluated?
Semiannually
In digital imaging, as the size of the image matrix increases,
- FOV increases
- pixel size decreases
- spatial resolution increases
2 and 3 only
Exposed silver halide crystals are changed to black metallic silver by the
reducers
Grid cutoff due to off-centering would result in
overall loss of density
The advantage(s) of high-kilovoltage chest radiography is (are) that
- exposure latitude is increased
- it produces long-scale contrast
- it reduces patient dose
1, 2, and 3
The exposure factors of 400 mA, 70 ms, and 78 kV were used to produce a particular radiographic density and contrast. A similar radiograph can be
produced using 500 mA, 90 kV, and
28 ms
Disadvantages of using low-kilovoltage technical factors include
- insufficient penetration
- increased patient dose
- diminished latitude
1, 2, and 3
Geometric unsharpness is directly influenced by
- OID
- SOD
- SID
1 only
Which of the following is/are associated with magnification fluoroscopy?
- Less noise
- Improved contrast resolution
- Improved spatial resolution
1, 2, and 3
Which of the following may be used to reduce the effect of scattered radiation on a finished radiograph? 1. Grids 2. Collimators 3. Compression bands
1, 2, and 3
Which of the following is (are) directly related to photon energy?
- Kilovoltage
- Milliamperes
- Wavelength
1 only
What information, located on each box of film, is important to note and has a
direct relationship to image quality?
Expiration date
If 40 mAs and a 200-speed screen–film system were used for a particular exposure, what new milliampere-seconds value would be required to
produce the same density if the screen–film system were changed to 800
speed?
10
An exposure was made using 8 mAs and 60 kV. If the kilovoltage was changed
to 70 to obtain longer-scale contrast, what new milliampere-seconds value is
required to maintain density?
4
Recorded detail can be improved by decreasing
- the SID
- the OID
- patient/part motion
2 and 3 only
Compression of the breast during mammo-graphic imaging improves the technical quality of the image because 1. geometric blurring is decreased 2. less scattered radiation is produced 3. patient motion is reduced
1, 2, and 3
Distortion can be caused by
- tube angle
- the position of the organ or structure within the body
- the radiographic positioning of the part
1, 2, and 3
As window level increases
brightness increases
What is the relationship between tissue attenuation coefficient in CT and its
related Hounsfield unit (HU)?
The greater the tissue attenuation coefficient, the higher the HU value
A grid usually is employed in which of the following circumstances?
- When radiographing a large or dense body part
- When using high kilovoltage
- When a lower patient dose is required
1 and 2 only
Exposure factors of 90 kV and 3 mAs are used for a particular nongrid
exposure. What should be the new milliampere-seconds (mAs) value if a
12: 1 grid is added?
15
An exposure was made using 300 mA, 40 ms exposure, and 85 kV. Each of the
following changes will decrease the radiographic density by one half except
a change to
10 mAs
Which of the following units is (are) used to express resolution?
- Line-spread function
- Line pairs per millimeter
- Line-focus principle
1 and 2 only
Which of the following is (are) methods used for x-ray film silver reclamation? 524 1. Photoelectric method 2. Metallic replacement method 3. Electrolytic method
2 and 3 only
In which of the following examinations should 70 kV not be exceeded? (A) Upper GI (UGI) (B) Barium enema (BE) (C) Intravenous urogram (IVU) (D) Chest
Intravenous urogram (IVU)
