Image Production: Image Acquisition and Evaluation Flashcards
166 - What will happen to radiographic density if mAs increases, and all other exposure variables remain constant?
A. Density will decrease
B. Density will remain unchanged, and radiographic contrast will increase
C. Density will increase
D. Density will remain unchanged, and radiographic contrast will decrease
C. Density will increase
Radiographic density and mAs have a direct correlation. As mAs increases, the radiography density will also increase if all other exposure variables stay unchanged.
167 - If all other exposure factors remain constant as kVp rises, what will happen to radiographic contrast and density?
A. Contrast will decrease, and density will remain unchanged
B. Contrast will increase and density will decrease
C. Contrast will decrease, and density will increase
D. Contrast and density will decrease
E. Contrast and density will increase
C. Contrast will decrease, and density will increase
An increase in kVp will result in a reduction in radiographic contrast and an increase in radiographic density, assuming that all other exposure variables stay the same. There is an inverse relationship between kVp and contrast and a direct relationship between kVp and density.
168 - What is the effect of increasing radiographic object to image receptor distance (OID) on acquired image detail?
A. Recorded detail will remain unchanged, and size distortion will decrease
B. As OID increases spatial resolution increases
C. As OID increases spatial resolution decreases
D. OID is unrelated to spatial resolution
E. Recorded detail will remain unchanged, and shape distortion will increase
C. As OID increases spatial resolution decreases
The capacity to distinguish between two adjacent anatomic structures as being different from one another can be defined as spatial resolution. Terms like definition and visibility of detail are also relevant. In terms of spatial resolution, line pairs per millimeter (lp mm) is used. Blur is the absence of optimal spatial resolution on a radiographic image. Screen film devices, when properly calibrated, offer very high spatial resolution, while electronic detectors are restricted by the size of their pixels. At a viewing distance of 25 centimeters, human eyes can differentiate a spatial resolution of 5 line pairs per millimeter. Spatial resolution and OID have an inverse relationship. Size distortion of the anatomical part is apparent and spatial resolution decreases with increasing OID. Moving an object farther away from the image receptor results in increased magnification. Consequently, an 8-inch OID would appear magnified to a greater extent than a 4 inch OID.
169 - Which of the following controls how much magnification is present on the radiographic image?
A. OID
B. SID
C. CR angulation
D. A, B, and C
E. A and B
E. A and B
Magnification is governed by the distances between the source and the image receptor (SID) and the object and the image receptor (OID). The tube’s distance from the image receptor is known as the SID. There will be less magnification on the resulting radiograph as SID is increased. The distance between the object and the image detector is known as the OID. There will be less magnification and visual distortion the closer the anatomic part is to the detector. Magnification is unrelated to CR angulation.
170 - Which change will occur if SID doubles?
A. Exposure rate will quadruple
B. Beam intensity reaching the IR will be one-fourth of the initial intensity
C. Exposure rate will double
D. Beam intensity reaching the IR will be one-half of the initial intensity
B. Beam intensity reaching the IR will be one-fourth of the initial intensity
An important factor influencing x-ray beam intensity which reaches the IR is the source-to-image-receptor distance (SID). The inverse-square law indicates that as the distance between the x-ray tube and the imaging detector increases, the intensity, exposure rate, and dose that contribute to radiographic density decrease. The beam intensity that results from halving the SID will be four times higher than the initial intensity. The resultant beam intensity will be one-fourth of the initial intensity if the SID is doubled. This is because, in accordance with the inverse-square law, the exposure rate is inversely proportional to the square of the distance.
171 - Which of the following statements about spatial resolution in relation to SID is correct?
A. There is an inverse relationship between SID and spatial resolution
B. As SID increases, spatial resolution decreases
C. SID and spatial resolution are directly related
D. Spatial resolution is unrelated to SID
C. SID and spatial resolution are directly related
The degree of divergence of the x-ray beam and the data captured on the radiograph are both influenced by geometric factors. Among these geometric factors is SID. There is a direct relationship between SID and recorded detail. Spatial resolution increases with increasing SID.
172 - After exposure and processing, the degree of darkness on the radiographic image is referred to as:
A. Resolution
B. Photographic factor
C. Contrast
D. Density
D. Density
The amount of exposure that reaches the image receptor is influenced by photographic imaging characteristics. After exposure and processing, radiographic density is the extent of blackness on the radiographic image.
173 - The spectrum of density variations seen on the radiographic image is known as the contrast scale. Which contrast-type involves limited variations in density, with considerable differences between densities?
A. Long-scale contrast
B. Short-scale contrast
C. Subject contrast
D. Developer contrast
B. Short-scale contrast
Short-scale radiographs are categorized as high-contrast because, although density differences are larger, there are generally fewer density steps, or fewer shades of gray, on the contrast scale. Because long-scale radiographs show more grayscale tones on the contrast scale but fewer noticeable density shifts, they are referred to as low-contrast images. When studying the lung fields, long-scale radiographs are desirable since slight differences in density could provide valuable diagnostic information.
174 - What impact will the usage of a grid have on film contrast if all other exposure parameters stay constant?
A. Contrast will remain unchanged, and radiographic density will increase
B. Contrast will decrease
C. Contrast will remain unchanged, and radiographic density will decrease
D. Contrast will increase
D. Contrast will increase
There is a clear correlation between radiographic contrast and grid utilization. Using a grid will improve radiographic contrast if all other exposure factors remain the same. Use of a grid and radiographic density exhibit an inverse relationship. Radiographic density will be reduced by using a grid.
175 - What effect does an increase in the amount of filtration in the X-ray beam’s path have on radiographic density and patient skin exposure?
A. Radiographic density increases, patient skin exposure decreases
B. Radiographic density increases, patient skin exposure increases
C. Radiographic density decreases, patient skin exposure increases
D. Radiographic density decreases, patient skin exposure decreases
D. Radiographic density decreases, patient skin exposure decreases
With implementation of a filter, radiographic density will decrease as there is less radiation available to expose the radiograph due to increased filtration in the path of the X-ray beam. The use of a filter also lessens the patient’s skin exposure.
176 - The relationship between radiographic contrast and beam restriction is best described by which of the following?
A. Radiographic contrast and beam restriction exhibit an inverse relationship
B. Beam restriction and radiographic contrast are unrelated
C. Greater beam restriction causes radiographic contrast to increase proportionately
D. Increasing beam restriction decreases radiographic contrast
C. Greater beam restriction causes radiographic contrast to increase proportionately
The radiographic density will be lower, and the radiographic contrast will be higher the more the x-ray beam is restricted.
177 - Consider the relationship between spatial resolution and patient motion. Which of the following will happen when motion increases?
A. Spatial resolution and patient motion exhibit a direct relationship
B. As patient movement increases, recorded detail increases
C. An increase in motion decreases spatial resolution
D. Patient movement and spatial resolution are unrelated
C. An increase in motion decreases spatial resolution
There is an inverse relationship between patient movement and spatial resolution. Increased patient motion will cause a deterioration in spatial resolution and an increase in unsharpness.
178 - Which combination would result in a more noticeable anode heel effect?
A. 72” SID, 14” x 17” IR
B. 40” SID, 14” x 17” IR
C. 72” SID, 10” x 12” IR
D. 40” SID, 8” x 10” IR
B. 40” SID, 14” x 17” IR
The anode heel effect becomes significantly more noticeable when a large-size IR and a short SID are used. At anode angles of 10 degrees or less, the anode heel effect is also discernible. More divergence of the X-ray beam is required to cover a greater IR size. The X-ray beam needs to deviate significantly more for coverage when the SID decreases. In practice, the X-ray beam diverges toward the cathode end of the beam; however, as it approaches the anode, X-ray photons are absorbed by the anode, causing the X-ray beam to eventually stop diverging further. This leads to a decrease in beam intensity at the anode end of the beam and is consistent with the anode heel effect.
179 - What is the name for a fluctuation in x-ray beam intensity which demonstrates a rise in intensity toward the cathode end of the beam and a decline in intensity toward the anode end?
A. Air gap phenomenon
B. Line-focus principle
C. Anode heel effect
D. Reciprocity law
C. Anode heel effect
The anode heel effect is a variation in x-ray beam intensity where the intensity increases toward the cathode end of the beam and decreases toward the anode end. The anode heel effect is most pronounced when imaging a body part with variable part thickness at its ends, such as the anteroposterior thoracic spine or femur, and when attempting to obtain images that require large field size in line with the long axis of the tube. By adjusting the anatomic part’s position to align its thicker end with the cathode end of the tube or by using a compensating filter, the anode heel effect can be mitigated. One type of compensating filter that would be suitable for minimizing the anode heel effect is a wedge filter.
180 - Low bone mass and deteriorating bone structure are the hallmarks of osteoporosis, a degenerative disease process that makes bones more brittle and raises the risk of fracture. How can osteoporosis progress influence radiographic contrast?
A. Increasingly destructive disease processes decrease radiographic contrast
B. Radiographic contrast is increased with osteoporosis
C. Osteoporosis has no effect on radiographic contrast
D. The less that osteoporosis progresses, the more radiographic contrast will decrease
A. Increasingly destructive disease processes decrease radiographic contrast
There is an inverse association between radiographic contrast and destructive bony disease processes. The more destructive a bony disease process is, the lower the radiographic contrast. Destructive disease processes exhibit a direct relationship to radiographic density. As the disease process progresses, the anatomic part undergoes less attenuation and radiographic density increases.
181 - The patient’s right femur is being examined by a radiographer. Which of the following would be appropriate to minimize the anode heel effect?
A. A wedge filter should be used placing the thicker part of the wedge near the proximal epiphysis
B. The femoral head should be directed toward the cathode end of the tube
C. The distal epiphysis should be directed toward the cathode end of the tube
D. The femoral head should be directed toward the anode end of the tube
B. The femoral head should be directed toward the cathode end of the tube
The anode heel effect is a variation in x-ray beam intensity where the intensity increases toward the cathode end of the beam and decreases toward the anode end. The anode heel effect is most pronounced when imaging a body part with variable part thickness at its ends, such as the anteroposterior thoracic spine or femur, and when attempting to obtain images that require large field size in line with the long axis of the tube. By adjusting the anatomic part’s position to align its thicker end with the cathode end of the tube or by using a compensating filter, the anode heel effect can be mitigated. One type of compensating filter that would be suitable for minimizing the anode heel effect is a wedge filter.
182 - A deviation from the true dimensions or shape of the anatomical part imaged is referred to as:
A. Magnification
B. Foreshortening
C. Distortion
D. Elongation
C. Distortion
An inaccurate display of the true size or shape of the anatomic part being imaged is called distortion. Shape distortion includes elongation and foreshortening. These may result from erroneous alignment of the X-ray tube, IR, or anatomic part being imaged. Magnification is a form of size distortion.
183 - Which of the following will cause the anatomic part to appear foreshortened?
A. Perpendicular alignment of the anatomic part, IR, and X-ray tube
B. Parallel alignment of the anatomic part, IR, and X-ray tube
C. Angulation of the anatomic part’s long axis relative to the IR
D. The anatomic part’s short axis is angulated with regard to the IR
C. Angulation of the anatomic part’s long axis relative to the IR
An anatomic part will appear foreshortened on the resultant radiograph when the long axis of the anatomic part is angled relative to the imaging receptor (IR). Orienting the IR, anatomical part, and X-ray tube to ensure they are parallel minimizes the shape distortion.
184 - Under which circumstance will image distortion be most prevalent?
A. The anatomic part is located further from the IR
B. The anatomic part is located closer to the X-ray source
C. The anatomic part is placed directly on the IR (i.e., tabletop examination)
D. A and B
E. B and C
D. A and B
Because of the location and form of anatomical structures within the body, radiographic images always have some intrinsic object unsharpness. The human body is composed of anatomical parts that are arranged in divergent planes. The three-dimensional forms of solid anatomic structures seldom coincide with the shape of the divergent beam. As a result, the forms of anatomical structures might be incorrectly represented, and some structures are depicted with more intrinsic distortion than others. Structures located further away from the imaging receptor (IR) exhibit more distortion than anatomic parts nearer the IR. Structures positioned closer to the X-ray source will be more distorted than anatomic parts positioned more distant from the X-ray source.
185 - The main factor that influences radiographic contrast is kVp. What impact will a rise in kVp have on radiographic contrast?
A. Increasing kVp will increase radiographic contrast
B. An increase in kVp will produce a low-contrast radiograph
C. An increase in kVp can only affect radiographic contrast when specific film and screen speed criteria are met
D. A short-scale contrast radiograph will result from an increase in kVp
B. An increase in kVp will produce a low-contrast radiograph
kVp is the primary factor that affects radiographic contrast. There is an inverse relationship between contrast and kVp. Contrast will decrease as kVp rises. Variations in mAs and SID, in comparison with kVp, have no influence on radiographic contrast.
186 - A radiographer uses a technique of 70 kVp at 6.4 mAs to perform an AP projection of a patient’s right shoulder. The same projection is performed on another patient whose shoulder is 3 cm thicker. What radiographic technique should be used?
A. 70 kVp at 6.4 mAs
B. 72 kVp at 6.4 mAs
C. 76 kVp at 6.4 mAs
D. 74 kVp at 6.4 mAs
C. 76 kVp at 6.4 mAs
Each anatomic part is assigned a specific value of milliampere seconds when a variable-kilovoltage technique is applied. The kilovoltage, or penetration, rises in proportion to part thickness. The radiographic exposure is increased by 2 kV for every centimeter that an anatomic part thickens. In this case, if a technique of 70 kVp at 6.4 mAs is used, and part thickness increases by 3 cm, a technique adjustment of 6 kVp is required (i.e., 2 kV x 3 cm). For this reason, it is necessary to note the size of the anatomical part during radiographic imaging.
187 - The radiographer must consider how the patient’s cast increases part thickness and influences the radiographic technique selected. For a medium-sized dry plaster cast, what kV increase is recommended?
A. 1 to 2 kV increase
B. 2 to 4 kV increase
C. 5 to 8 kV increase
D. 12 to 15 kV increase
C. 5 to 8 kV increase
An increase of 5 to 8 kVp would be necessary for a dry plaster cast. If kVp remains unchanged, a 50 to 60% mAs increase would also be acceptable. Either an 8 to 10 increase in kVp or a 100% increase in mAs would be necessary for a wet plaster cast. A fiberglass cast often calls for a mAs increase between 25% and 30% or a kVp increase of 3 to 4.
188 - When a radiographer must maintain a uniform density over a range of distances, which formula may they use?
A. The 15% rule
B. The inverse square law
C. The direct square law
D. The line-focus principle
C. The direct square law
The direct square law formula is also called the density maintenance formula. When the radiographer must maintain a consistent density when there is a change in distance, the direct square law formula is applied.
189 - When choosing a technique, the radiographer must consider the patient’s age. One of the challenges of working with pediatric patients is the likelihood of radiographic motion. How can the radiographer modify their technical factors to overcome this challenge?
A. Increase exposure time, increase mA
B. Decrease exposure time, increase mA
C. Increase exposure time, decrease mA
D. Decrease exposure time, decrease mA
B. Decrease exposure time, increase mA
Changes in mAs, mA, or time have a direct relationship with exposure to the image receptor (IR). This indicates that IR exposure increases when mAs, mA, or time increase, and decreases when mAs, mA, or time decrease. In order to maintain mAs, mA must decrease when time increases, and time must decrease when mA increases. It is possible to minimize any possible motion displayed on the resultant radiograph by using a shorter exposure period. When imaging mobile pediatric patients, this is a helpful modification.
190 - An ideal radiographic image may be challenging to obtain from a patient with a higher BMI. Radiation scatter may cause an image’s quality to deteriorate when imaging thicker anatomic parts. Which one of these techniques can be applied to reduce resultant scatter-related image deterioration?
A. Use a smaller air gap between the anatomic part and the detector
B. Utilize a grid
C. Increase the kVp
D. Implement a larger field of view
B. Utilize a grid
Using an anti-scatter grid, a larger air gap between the anatomic part and the IR, and a smaller field of view (FOV) are a few potential techniques that may be implemented to limit scattered radiation.
191 - A radiographer is performing a small bowel series on a patient involving the use of an iodinated water-based contrast medium. Which of the following modifications to the technical factors is appropriate?
A. It is recommended to implement a kVp ≤ 70
B. Exposure time should be decreased
C. A lower kVp should be selected compared to that which is used for a standard abdominal radiograph
D. A kVp of ≥ 80 should be utilized
A. It is recommended to implement a kVp ≤ 70
Negative radiographic contrast agents are radiolucent (i.e., air), whereas positive contrast materials are radiopaque. The most common application of barium sulfate, a radiopaque positive contrast material, is for imaging examinations involving the digestive tract. To adequately penetrate the barium, higher kVp is necessary. Positive contrast agents also include iodinated water-based contrast media (i.e., Conray). However, using voltages considerably higher than 70 kV with these materials is not permitted due to iodine’s K-edge binding energy. The contrast agent’s impact will be eliminated at higher kilovoltage levels.
192 - A radiographer uses a grid with a 5:1 grid ratio. What is the mAs multiplication factor?
A. 1
B. 4
C. 6
D. 2
D. 2
Utilizing a grid in X-ray imaging presents both advantages and disadvantages. Grids play a crucial role in eliminating scattered radiation, thereby ameliorating overall image quality by reducing radiographic imaging fog. Furthermore, employing a grid enhances image contrast by limiting the amount of scattered radiation that reaches the detector, resulting in clearer delineation of anatomical structures.
However, the use of grids is not without its drawbacks. A significant disadvantage lies in the grid’s ability to attenuate the X-ray beam, leading to a reduction in radiographic density unless adjustments are made to technique factors, notably by increasing exposure parameters such as mAs. Compensatory modifications in mAs are imperative when a grid is positioned between the patient and the image receptor (IR) to maintain adequate radiographic density. Charts exist to determine the requisite mAs adjustments based on the grid ratio. For instance, in the case of a 5:1 grid, the mAs multiplication factor is 2. When an 8:1 grid is used, the mAs multiplication factor is 4. A 12:1 grid requires a mAs multiplication factor of 5. A 16:1 grid necessitates a mAs multiplication factor of 6.. Consequently, the necessary escalation in mAs to sustain radiographic density often translates into a heightened patient dose to counteract the attenuation effects induced by the grid. Consequently, the augmented radiation dose received by the patient is a pertinent concern in terms of radiation safety.
While grids contribute to enhanced image quality by mitigating scattered radiation and enhancing contrast, they also entail the drawback of attenuating the X-ray beam, potentially necessitating an increase in patient dose. Thus, meticulous consideration and optimization of technique factors are essential when incorporating grids in X-ray imaging protocols to strike a delicate balance between image quality and radiation dose.
193 - What are the effects on attenuation and radiographic density when a part’s atomic number increases?
A. Attenuation increases, radiographic density increases
B. Attenuation decreases, radiographic density decreases
C. Attenuation decreases, radiographic density increases
D. Attenuation increases, radiographic density decreases
D. Attenuation increases, radiographic density decreases
The atomic number is one variable that affects a body part’s capacity to absorb radiation. Attenuation will rise with an object’s atomic number, resulting in a reduction in radiographic density.
194 - If the required mAs is too low, use of automatic exposure control (AEC) may result in quantum mottle. How might this be mitigated?
A. Increasing kVp will cause an increase in mAs
B. Only kVp is adjusted with use of AEC
C. This can be avoided by lowering kVp, which will cause mAs to increase
D. It is not possible to expose using AEC if the mAs is set too low
C. This can be avoided by lowering kVp, which will cause mAs to increase
If the necessary mAs is too low, use of an automatic exposure control (AEC) technique may result in quantum mottle. This can be avoided by lowering kVp, which will cause mAs to increase.
195 - As film and screen speed increase, what happens to the recorded detail of the radiographic image?
A. Recorded detail decreases
B. Recorded detail increases
C. Film speed has no effect on spatial resolution
D. Screen speed has no effect on spatial resolution
E. C and D
A. Recorded detail decreases
Larger phosphor and thicker-layered silver halide crystals are used to achieve faster film and screen speeds. Because of the coarseness of the phosphor and crystal grain utilized to create the image, recorded detail decreases with increasing screen and film speeds. A standard extremity cassette is typically 100 speed, for instance. This increased speed leads to loss of detail.
196 - The effective focal spot also goes by the terminology:
A. Projected focal spot
B. Useful focal spot
C. Actual focal spot
D. A and B
E. A and C
D. A and B
One geometric factor that directly influences the amount of penumbra captured on the radiographic image is the focal spot size. Recorded detail reduces as focal spot size increases. Density and contrast are unaffected by variations in focal spot size while an adequate mAs is maintained. The measurement of the actual focal spot is taken perpendicular to the anode’s surface. The size of the exposure filament is reflected in its measurement.
The projected or useful focal spot are alternative names for the effective focal spot. The measurement of the effective focus spot is taken perpendicular to the x-ray tube’s long axis. The effective focal spot decreases with decreasing anode angle. The line focus principle refers to this decrease in focal size that is directed toward the IR, relative to the size of the actual area on the anode’s surface which is subjected to incoming electrons.
197 - What happens to the effective focal spot as the anode’s angle decreases?
A. The effective focal spot increases
B. The effective focal spot remains unchanged, while the actual focal spot increases
C. The effective focal spot decreases
D. The effective focal spot remains unchanged, while the actual focal spot decreases
C. The effective focal spot decreases
One geometric factor that directly influences the amount of penumbra captured on the radiographic image is the focal spot size. Recorded detail reduces as focal spot size increases. Density and contrast are unaffected by variations in focal spot size while an adequate mAs is maintained. The measurement of the actual focal spot is taken perpendicular to the anode’s surface. The size of the exposure filament is reflected in its measurement.
The projected or useful focal spot are alternative names for the effective focal spot. The measurement of the effective focus spot is taken perpendicular to the x-ray tube’s long axis. The effective focal spot decreases with decreasing anode angle. The line focus principle refers to this decrease in focal size that is directed toward the IR, relative to the size of the actual area on the anode’s surface which is subjected to incoming electrons.
198 - What happens to the recorded detail of the radiographic image as focal spot size increases?
A. Recorded detail decreases
B. Spatial resolution and focal spot size are directly related
C. Changes in focal spot size have no effect on recorded detail
D. Spatial resolution increases
A. Recorded detail decreases
One geometric factor that directly influences the amount of penumbra captured on the radiographic image is the focal spot size. Recorded detail reduces as focal spot size increases. Density and contrast are unaffected by variations in focal spot size while an adequate mAs is maintained. The measurement of the actual focal spot is taken perpendicular to the anode’s surface. The size of the exposure filament is reflected in its measurement.
The projected or useful focal spot are alternative names for the effective focal spot. The measurement of the effective focus spot is taken perpendicular to the x-ray tube’s long axis. The effective focal spot decreases with decreasing anode angle. The line focus principle refers to this decrease in focal size that is directed toward the IR, relative to the size of the actual area on the anode’s surface which is subjected to incoming electrons.
199 - Which of the following factors affects image contrast?
A. Window width
B. Quantity of voxels
C. Window level
D. Quality of pixels
A. Window width
An image’s brightness and density are controlled by the window level. The contrast and grayscale presentation of the tissue under study in the image are determined by the window width. A low contrast image (i.e., long grayscale) results from a wide window width. A narrow window width will result in a high contrast image (i.e., short grayscale).
200 - An image matrix is used to create digital images. A matrix is composed of:
A. A series of rows
B. A series of columns
C. Pixels
D. Picture elements
E. All of the above
E. All of the above
An image matrix is used to create digital images. Pixels, or picture elements, are created by a sequence of rows and columns that make up the image matrix.
201 - In computed radiography (CR), an interference pattern that resembles slightly wavy linear lines results when the lead strip pattern (i.e., frequency) of a stationary grid matches the scanning (sampling) pattern of the scanner/reader. What is the name of this interference pattern?
A. Aliasing
B. Moiré effect
C. Grid cutoff
D. Vignetting
E. A and B
E. A and B
The Moiré effect, sometimes referred to as aliasing in computed radiography (CR), is an interference pattern that appears when a stationary grid’s lead strip pattern, or frequency, coincides with the scanning pattern of the scanner or reader. Another name for the scanning pattern is a sampling pattern. The resultant interference pattern is a succession of aligned, slightly wavy lines.
202 - Within a matrix, pixel size increases. How is spatial resolution affected?
A. Spatial resolution is enhanced
B. Spatial resolution is unaffected, but field of view decreases
C. Spatial resolution decreases
D. Spatial resolution is unaffected, but field of view increases
C. Spatial resolution decreases
Pixel size in digital imaging is calculated by dividing the FOV (field of view) by the matrix. FOV and matrix size are unrelated. Although, modifications to the FOV or matrix size have an impact on pixel size. For instance, pixel size decreases with increasing matrix size and increases with increasing FOV. Resolution has an inverse relationship with pixel size. Resolution declines as pixel size rises.
203 - The degree of resolution that has been transmitted to the IR is indicated by each of the following, except:
A. Line pairs per millimeter
B. Modulation transfer function
C. Line spread function
D. Pixel pitch
D. Pixel pitch
The ability of an imaging modality to distinguish between two nearby structures as separate entities is referred to as spatial resolution. Line pairs per millimeter (lp/mm), line-spread function (LSP), or modulation transfer function (MTF) can be used to indicate the degree of resolution transferred to the IR. This degree of resolution is dependent on the resolving capability of each system component. The MTF quantifies the amount of data lost between the part being imaged and the IR.
204 - Which of the following makes use of a photostimulable phosphor?
A. Direct digital radiography
B. Digital radiography
C. Computed radiography
D. B and C
E. A, B, and C
D. B and C
A reusable solid-state image receptor and photostimulable phosphor (PSP) are used in computed radiography (CR), a type of digital radiography. The active ingredient in the cassette-based CR system is europium-activated barium fluorohalide. The PSP’s sensitivity is comparable to that of a 200-speed film/screen system.
205 - What establishes the number of displayable shades of gray and contrast resolution of a radiographic image?
A. S-number
B. Exposure index
C. Pixel size
D. Bit depth
D. Bit depth
A two-dimensional picture element is called a pixel. The depth of a matrix of pixels is represented by the third dimension, or “Z” dimension, and is known as a “voxel,” or volume element. The depth of the voxel is relative to the quantity of bits needed to characterize the gray level that each pixel can assume. Bit depth is defined as the number of bits per pixel. Higher bit depths are linked to more gray shades and higher contrast resolution.
206 - Which system offers a greater detective quantum efficiency?
A. DR system utilizing a-Se
B. Film-screen system
C. DQE is equivalent amongst all imaging systems
D. DR system utilizing CsI phosphor
D. DR system utilizing CsI phosphor
The cassette-less direct digital radiography system uses solid-state detectors. There are two approaches to processing: the first applies a cesium iodide scintillation phosphor to an active matrix array of amorphous silicon photodiodes, while the second approach does not. Remnant radiation directly interacts with a thin layer of amorphous selenium (a-Se) in the approach that does not make use of the phosphor coating, creating electron hole pairs (EHP). The EHP signal charges the active matrix array (AMA) of thin-film transistors (TFTs). The a-Se processing method without phosphor coating can yield better spatial resolution. In contrast, the CsI phosphor technique offers two advantages: a lower radiation exposure to the patient and a higher detective quantum efficiency (DQE).
207 - Which S-number denotes an excess of exposure, and which denotes an underexposure?
A. <100 overexposure; >250 underexposure
B. >100 overexposure; <250 underexposure
C. >250 overexposure; <100 underexposure
D. <25 overexposure; >100 underexposure
A. <100 overexposure; >250 underexposure
Some manufacturers of diagnostic digital imaging equipment employ an exposure index system which assigns an S-number. The amount of radiation striking the image receptor is inversely related to the S-number. An ideal S-number ranges between 100 and 250. A value of more than 250 denotes underexposure, whereas a value of less than 100 implies overexposure.
208 - Exposure index is an entity of:
A. Film-screen systems
B. Computed radiography
C. Digital radiography
D. Direct digital radiography
D. Direct digital radiography
The exposure index, or EI, is a numerical value that represents the exposure that the image receptor received and is used in the majority of direct digital imaging systems. It is derived from logarithmic calculations and is directly proportional to the intensity of radiation that strikes the detector. Let’s say an appropriate EI, for instance, ranges between 1.0 and 1.8; an EI below 1.0 would indicate underexposure, and a reading beyond 1.8 would indicate overexposure.
209 - What is the name for the randomized X-ray photon or quanta disturbance that can be seen throughout the radiographic image?
A. Quantum mottle
B. Fog
C. Fluorescence
D. Phosphorescence
A. Quantum mottle
Some radiographs produced with a very fast imaging system can display a granular appearance known as quantum mottle. It is characterized as a random disruption of X-ray photons or quanta visible throughout the radiographic image. This is typically generated when trying to capture images of anatomical regions with low tissue density and a rapid exposure time. When utilizing automatic exposure control (AEC) technology, quantum mottle is relatively common. A lower mA setting can be used to extend the exposure period to compensate for the existence of quantum mottle with a phototimer unit.
210 - Which of the following would impair contrast resolution?
A. Low signal to noise ratio (SNR)
B. Remnant radiation
C. High signal to noise ratio (SNR)
D. Increasing mAs by >15%
A. Low signal to noise ratio (SNR)
The actual signal and anatomical representation of a radiographic image are measured in proportion to noise (i.e., spurious quantum mottle) using a metric known as the signal to noise ratio (SNR). A low SNR is associated with a substantially reduced contrast resolution and a noisy, granular imaging image. As SNR rises, overall image resolution improves. In radiography, the square root of the number of photons delivered and the contrast level are proportional to the SNR and perceived noisiness of the image. The SNR can be increased via methods of increasing photon count, such as by raising the mAs.
211 - What is the fluoroscopic resolution range?
A. 8-11 lp/mm
B. 5-8 lp/mm
C. 1-3 lp/mm
D. 13-15 lp/mm
C. 1-3 lp/mm
A fluoroscopic image has a resolution of 1–3 line pairs per millimeter (lp/mm). In contrast, detail-enhancing screens in film-screen systems are able to display up to 15 lp/mm
212 - What is the typical scanning rate of image frames in a fluoroscopic TV monitor system?
A. 14 frames per second
B. 52 frames per second
C. 8 frames per second
D. 30 frames per second
D. 30 frames per second
A television monitor system, along with a mirror optics system and Patterson screen, are several ways to observe a fluoroscopic image. Using the TV monitor technology, a pattern made up of several imaging frames composed of multiple scanlines and presented in an interlacing pattern creates the displayed video image. For these image frames, a scan rate of about 30 frames per second is employed.
213 - Acquisition is the process of obtaining and recreating an image on a digital platform. Digital values produce a graph of the exposure information called a histogram. What is the name of the histogram which displays luminance values obtained during image acquisition?
A. Sensitometric table
B. S-number
C. Exposure index
D. Look-up table
D. Look-up table
A look-up table is an image acquisition histogram that shows brightness values. In order to achieve the proper density and contrast in the final image, each pixel is converted to a new gray value, called gray level transformation.
214 - What is vignetting?
A. Loss of detail and decrease in brightness at the center of a fluoroscopic image
B. Decrease in clarity and brightness at the edge of a fluoroscopic image
C. Decreased detail and an increase in brightness at the edge of a fluoroscopic image
D. Enhanced detail and increased brightness at the center of a fluoroscopic image
B. Decrease in clarity and brightness at the edge of a fluoroscopic image
Vignetting is the noticeable reduction of detail and luminance at the edge of the fluoroscopic image caused by the curved input surface of the image intensification tube
215 - Which sensitometric monitoring instrument measures the opacity recorded on the processed radiograph?
A. Sensitometer
B. Densitometer
C. Penetrometer
D. Look-up table
B. Densitometer
Penetrometers, sensitometers, and densitometers are among the equipment used in sensitometric monitoring. These devices create perceptible effects relative to contrast, fog, density, and speed variations. Another name for a penetrometer is a step wedge; it needs to be calibrated so that exposure factor adjustments can be made using step variations in film densities as a guide. The optical densities or opacities captured on a processed radiograph are measured using a densitometer. For processor evaluation, a sensitometer makes use of a calibrated light source that can generate reproducible density strips.
216 - Which recording system or systems functions using an electrical signal delivered from the TV camera circuitry connected to the output end of the image intensifier?
A. Digital storage device
B. Photospot film device
C. Magnetic tape recorder
D. A and C
E. A, B, and C
D. A and C
A photospot film device, cinefluoroscopic device, spot films, digital storage device, and magnetic tape recorder are just a few of several recording systems available. An electronic signal sent from the TV camera circuitry attached to the image intensifier’s output end drives the digital storage device and magnetic tape recorder.
217 - In a diagnostic radiology setting, which test would expose a patient to the highest degree of acute radiation exposure?
A. Scoliosis series
B. Rhese and Haas cranial projections
C. Voiding cystourethrogram
D. AP lumbar spine radiograph
C. Voiding cystourethrogram
The greatest cause of acute radiation exposure for patients in the diagnostic radiology setting is fluoroscopy.
218 - Which relevant information must be included on a radiographic image in order for it to be accepted as valid legal evidence in a court case?
A. The radiographer’s name or initials
B. The study date and time
C. The name of the facility where the radiograph was produced
D. Patient date of birth
C. The name of the facility where the radiograph was produced
In medical disputes, X-ray images are frequently subpoenaed as evidence in court. Any radiographic image that is intended to be used as valid legal evidence needs to include the following essential information: the patient’s identity, the name of the facility where the X-ray examination was conducted, the study date, and a radiographic marker indicating laterality. Additional patient demographics like the patient’s date of birth, the name of the referring physician, the time of day the study was conducted, and the identity or initials of the radiographer conducting the examination are all helpful details that may be included but are not deemed necessary for legal purposes.
219 - What is the cause of an artifact which appears as a black, spider-like region on the radiograph?
A. Static electricity
B. Use of a very fast film-screen system
C. Increased developer temperature
D. Use of a stationary grid
A. Static electricity
Radiographic film exposed to the open air may cause a static electricity discharge. This shows up as a black, spider-like artifact on the radiograph.
220 - Which of the following would result in a higher “base plus fog” density on an imaging film?
A. Film storage at high temperatures
B. Upright film storage
C. Film storage at low humidity
D. Storage in a lead-lined cabinet
A. Film storage at high temperatures
In healthcare facilities that still use film, the radiographer must ensure that the film is stored properly. To avoid pressure desensitization that happens when several boxes are stacked flat on top of one another, film boxes should always be stored standing on edge. In addition, storage environments should be dry and cool, with a temperature between 50- and 70-degrees Fahrenheit and a humidity level between 40 and 60%. Film aging is exacerbated by storage at high temperatures, which will increase the “base plus fog” density on the film.
