Chapter 13: Radiographic Image Characteristics
Which combination of variables will results in a radiograph with the lowest receptor exposure? (letter) a. 100 kVp, 50 mAs, 14x17 receptor b. 85 kVp, 100 mAs, 10x12 receptor c. 75 kVp. 50 mAs, 14x17 receptor d. 85 kVp, 25 mAs, 10x12 receptor
D
The greater the OID, the ________ the magnification will be. a. greater b. less
greater
The greater the number of photons (intensity) that reach the image receptor, the: a. greater the penumbra b. greater the contrast c. greater the density d. lower the contrast
greater the density
Choose the term that is synonymous with short gray scale. a. high contrast b. low contrast c. many shades of gray
high contrast
An image with high spatial resolution would also be described as having: a. high blur b. high mottle c. high sharpness d. high distortion
high sharpness
An image is blurred. To increase sharpness of detail, the technologist could: a. increase exposure time b. decrease kVp and mAs c. use a double screen cassette d. increase SID
increase SID
A decubitus radiograph is acquired using 72 kVp, a 12:1 grid, 72 inch SID, 600 mA, and using AEC. Which of these variable modifications will decrease the exposure time? a. decrease kVp b. increase the grid ratio c. increase mA d. increase SID
increase mA
If only mAs increases, then IR intensity and patient absorbed dose ______________ a. increase, decrease b. decrease, increase c. increase, increase d. decrease, decrease
increase, increase
When a larger focal spot size is used, how will it affect the focal spot blur? a. increased b. decreased c. no change
increased
Which of these changes will decrease blur in a radiographic image? a. increased SID b. decrease SOD c. decrease kVp d. increased FSS
increased SID
Long-scale contrast radiographs are obtained using: a. decreased mAs b. increased mAs c. decreased kVp d. increased kVp
increased kVp
Long-scale contrast radiographs are obtained using: a. increased mAs b. decreased mAs c. increased kVp d. decreased kVp
increased kVp
Which of these factors are expected to decrease spatial resolution in the radiographic image? a. increased motion b. increased kVp c. increased mAs d. increased SID
increased motion
Increasing the SID results in decreased beam divergence and: a. decreased spatial resolution b. increased spatial resolution c. no change in spatial resolution
increased spatial resolution
The area of blue around the image is known as the: a. photoelectric effect b. penumbra c. contrast d. magnification factor
penumbra
A form of involuntary motion
peristalsis
Calculate the focal spot blur for a radiograph acquired using a 40 inch SID, 2 inch OID, and a 0.1 inch FSS. a. 0.01 inch b. 0.0053 inch c. 1.9 inch d. 0.019 inch
0.0053 inch
If a radiograph is produced using a mA of 400 and 0.05 seconds, how should the exposure time be changed if the mA is decreased to 200? a. 0.025 seconds b. 0.015 seconds c. 0.20 seconds d. 0.10 seconds
0.10 seconds
The values below were recorded on four different x-ray imaging systems. Which of these values represents the highest level of geometric sharpness? a. 20 lp/mm b. 18 lp/mm c. 16 lp/mm d. 14 lp/mm
20 lp/mm
An image of the sacrum measures 25 cm long on the film. The radiograph was taken under the following conditions: SID = 100 cm and OID = 75 cm. Calculate and select the correct magnification factor. a. 1.33 b. 0.9 c. 2 d. 4
4
If all other exposure variables remain constant, which of these OIDs will produce a radiograph with the least amount of image blur? a. 72 inches b. 40 inches c. 12 inches d. 4 inches
4 inches
Density differences on an image
Contrast
Which of the following would have the most effect on magnification of the image on a finished radiograph? a. OID b. motion c. focal spot size d. system speed
OID
The magnification factor will be 2 when the: (letter) a. SID = SOD b. SID = OID c. SOD = OID d. OID > SOD e. OID < SOD
D
Degree of blackness on an image
Density
Misrepresentation of an object on an image, either in its size of in its shape
Distortion
Size distortion or magnification will be affected by all of the following except: a. SID b. SOD c. OID d. FSS
FSS
Size distortion will be affected by all except the following? a. SID b. SOD c. OID d. FSS
FSS
Type of distortion that makes an object appear larger than its actual size
Magnification
___________ is the degree of blackening on the film. a. OD b. radiographic density c. subject contrast d. tissue thickness
OD
Recorded detail can be enhanced by decreasing the: a. OID b. SID c. mAs d. kV
OID
The primary controlling factor for magnification is: a. kVp b. mAs c. focal spot size d. OID
OID
What is the relationship between matrix size and radiographic spatial resolution? a. as matrix size increases, spatial resolution decreases b. matrix size has no effect on spatial resolution c. as matrix size increases, spatial resolution increases
as matrix size increases, spatial resolution increases
A radiographic image with a low level of penumbra could also be described as having: (select all that apply) a. high spatial resolution b. high blur c. high sharpness
a and c
Changing the kVp from 60 to 70 kVp and decreasing the mAs by one-half results in: a. a shorter scale of contrast b. increased optical density c. a longer scale of contrast d. decreased optical density
a longer scale of contrast
The body part under study should be placed as _________ as possible to the IR: a. close b. far away
close
Using as large a SID as possible, will ____________ size distortion. a. increase b. decrease
decrease
A UGI image is blurred. Based on the type of exam being conducted, to increase sharpness of detail the technologist could: a. decrease the exposure time b. use a single screen cassette c. decrease kVp and mAs d. decrease SID
decrease exposure time
In order to increase contrast, the technologist should: a. increased mAs b. decrease kVp c. increase SID d. decreased grid ratio
decrease kVp
An increase in the SID will: a. increase penumbra b. increase blur c. decrease penumbra d. no change in penumbra
decrease penumbra
Scatter and radiation fog have what effect on radiographic quality? a. reduce penumbra of the image b. create penumbra in the image c. decrease the contrast of the image d. increase the contrast of the image
decrease the contrast of the image
As matrix size increases, pixel size: a. increases b. decreases c. stays the same
decreases
Occurs when the object is parallel to the IR, but the x-ray tube is angled: a. elongation b. foreshortening
elongation
SOD = SID + OID. T/F?
false
In a direct capture radiography system, a decreased detector element (DEL) size results in: a. decreased spatial resolution b. increased spatial resolution c. no change
increased spatial resolution
Digital receptor systems with a large DEL pitch will have: a. low spatial resolution b. high spatial resolution c. pitch does not affect spatial resolution
low spatial resolution
The space between detector elements is called the: a. matrix size b. bit depth c. pitch d. exposure latitude
pitch
The space between pixels in a digital image is called the: a. pitch b. matrix size c. bit depth d. exposure latitude
pitch
To calculate the magnification factor: a. divide the SID by the OID b. divide the object size by the image size c. divide the SID by the SOD d. divide the OID by the SID
divide the SID by the SOD
The magnification equation is "Image size/object size = SOD/SID". T/F?
false
The only factor that alters image sharpness is: a. mAs b. kVp c. anode material d. focal spot size
focal spot size
Which of the following factors have no effect on contrast? a. kVp b. focal spot size c. grid ratio d. beam restriction of collimation
focal spot size
Occurs when the object is at an angle to the IR, but the central ray is perpendicular to the IR: elong/fore?
foreshortening
Radiographic contrast is defined as: a. the difference in densities between adjacent areas b. the difference in attenuation between adjacent areas c. the difference in scattering between adjacent areas d. the difference in bremsstrahlung between adjacent areas
the difference in densities between adjacent areas
In a radiographic image, focal spot blur is decreased by increasing: a. the size of the x-ray field b. the size of the focal spot in the x-ray tube c. the distance from the focal spot to the patient d. the patient motion
the distance from the focal spot to the patient
Spatial resolution in digital radiography is defined as: a. the structural sharpness recorded in the radiograph b. the total number of brightness level in the radiograph c. the amount of geometric distortion displayed in the radiograph d. the total number of photons absorbed by the image receptor
the structural sharpness recorded in the radiograph
Image gray-scale is defined as: a. the total brightness levels that are visible in a radiographic image b. the total amount of blur recorded in a radiographic image c. the total brightness levels that an imaging monitor is capable is displaying
the total brightness levels that are visible in a radiographic image
Image contrast is defined as: a. the visible difference in recorded detail between two different radiographs b. the visible difference in brightness between two areas in an image c. the visible difference in visible detail between two different radiographs
the visible difference in brightness between two areas in an image
Which of these anatomical parts can be an indicator of the spatial resolution recorded in a radiographic image? a. bowel gas b. trabecular bone c. muscular structures d. fat tissues
trabecular bone
For the least amount of shape distortion, the object should be parallel to the IR, and the central ray should be perpendicular to both the object and the IR. T/F?
true
The magnification factor is = SID/SOD. T/F?
true
Which of these variables affect the spatial resolution recorded in the radiographic image? a. SID b. kVp c. mAs
SID
Measured using lp/mm
Sharpness
An image with high-contrast would also have these characteristics: (select all that apply) a. long gray scale b. short gray scale c. few shades of gray d. many shades of gray
b and c
If only kVp increases, then contrast ________ and patient absorbed dose ____________. a. increase, decrease b. decrease, increase c. increase, increase d. decrease, decrease
decrease, decrease
If the kV is increased, the resulting image should exhibit ______ contrast. a. increased (short scale) b. increased (long scale) c. decreased (short scale) d. decreased (long scale)
decreased (long scale)
Consider this scenario: During a cross-table lateral c-spine you decrease the SID from 72 inches to 60 inches. How will this modification affect the detail recorded in the image? a. no change in recorded detail b. increased recorded detail c. decreased recorded detail
decreased recorded detail
Consider this scenario: During a routine x-ray of an extremity, you change the exposure settings from the small filament to the large filament. How will this change affect the spatial resolution? a. decreased spatial resolution b. increased spatial resolution c. no change in spatial resolution
decreased spatial resolution
Increasing FSS has what effect on spatial resolution? a. decreased spatial resolution b. increased spatial resolution c. no change in spatial resolution
decreased spatial resolution
Increasing the OID from 1 inch to 2 inches will result in: a. decreased spatial resolution b. increased spatial resolution c. no change in spatial resolution
decreased spatial resolution
Which of the following has/have no effect on sharpness of detail? a. penumbra b. motion c. density d. lp/mm
density
Which of the following has/have no relation to sharpness or recorded detail? a. penumbra b. motion c. density d. lp/mm
density
Density and mAs have what relationship? a. direct b. indirect c. none
direct
A variation from the true shape of the part being radiographed is defined as: a. misrepresentation b. facsimile c. magnification d. distortion
distortion
If the central ray is not placed so that it is directed through the center of the anatomy, the radiographic quality most affected will be: a. density b. contrast c. detail d. distortion
distortion
A satisfactory x-ray of the wrist is produced using a technique of 300 mA, 15 milliseconds, 50 kVp, and a SID of 40 inches. How should the mA be changed if the exposure time is decreased to 10 milliseconds? a. 200 mA b. 450 mA c. 255 mA d. 185 mA
450 mA
If all other exposure variables remain constant, which of these OIDs will produce a radiograph with the highest level of spatial resolution? a. 12 inches b. 5 inches c. 72 inches d. 60 inches
5 inches
Which type of image represents high contrast? (letter) a. mostly black and white, few shades of gray b. few blacks and whites, lots of shades of gray
A
Calculate the magnification factor for a radiograph made with a 40 inch SID and a 4 inch OID. a. 10 b. 0.9 c. 0.055 d. 1.11
1.11
A radiograph of the sella turcica was performed using an SID of 40 in. The sella turcica has a 10 in OID. What is the magnification factor of the sella turcica? a. 0.25 b. 0.75 c. 1.33 d. 4.0
1.33
What is the magnification factor with a 40-inch SID and a 30-inch SOD? a. 0.75 b. 1.33 c. 1.2 d. 0.80
1.33
An x-ray of the chest uses a 72 inch SID. If the image of the heart measures 12 cm and the actual heart measures 7 cm, what is the magnification factor? a. 5.0 b. 9.0 c. 1.7 d. 0.58
1.7
Which of the following combination of factors will provide the greatest detail? (letter) a. short SID, short OID, small FSS b. long SID, short OID, small FSS c. long SID, long OID, large FSS d. short SID, long OID, large FSS
B
Which combination of variables will results in a radiograph with the highest contrast? (letter) a. 101 kVp, 54 mAs, 1 mm filament b. 80 kVp, 100 mAs, 2 mm filament c. 74 kVp, 60 mAs, 1 mm filament d. 120 kVp, 54 mAs, 2 mm filament
C
Which of the following would improve radiographic quality if patient motion is a problem? (letter) a. 0.6 mm focal spot, 100 mA, 0.25s b. 0.6 mm focal spot, 200 mA, 0.125s c. 0.6 mm focal spot, 300 mA, 0.083s d. 1.2 mm focal spot, 500 mA, 0.050s
C
Tube angle toward the head
Cephalad
Type of shape distortion that makes an object appear smaller than its actual size
Foreshortening
Aluminum step wedge
Penetrometer
Blur, occurs around the edge of an image
Penumbra
Radiographic contrast depends on: a. tissue thickness b. tissue density c. kVp d. all of the above
all of the above
Subject contrast depends on: a. tissue thickness b. tissue density c. tissue atomic number d. all of the above
all of the above
Which of these changes will improve the spatial resolution recorded in the radiographic image? a. decrease FSS b. decrease OID c. increase SID d. all of the above
all of the above
Which of these equipment factors can influence spatial resolution in radiography? a. detector element (DEL) size b. detector element (DEL) pitch c. matrix size d. pixel size e. all of the above
all of the above
The primary factor that controls image contrast is the: a. kVp b. mAs c. SID d. focal spot size
kVp
A radiograph has been determined to have high contrast. This means that the density differences between the structures are: a. relatively small b. exactly equal c. large d. greater than 0.5 on a densitometer reading
large
The degree of spatial resolution is determined by: a. line focus principle b. line pairs per millimeter c. spinning top test d. wire mesh test
line pairs per millimeter
The spatial resolution of a radiographic system is measured with units of: a. line pairs per millimeter b. milligray c. milligray-centimeters squared d. bits
line pairs per millimeter
Low contrast is defined by: a. short gray scale b. long gray scale c. few shades of gray
long gray scale
Which contrast is produced with a higher kV: a. short scale b. long sclae
long scale
Long gray scale is defined as: a. high contrast b. low contrast c. few shades of gray
low contrast
The primary factor that controls density is: a. kVp b. grids c. mAs d. SID
mAs
A variation from the true size and enlargement of the part being radiographed is defined as: a. contrast resolution b. facsimile c. magnification d. shape distortion
magnification
A high-contrast film has a _____________ latitude. a. wide b. narrow
narrow
Do either the mAs or SID used affect the radiographic contrast produced? a. yes b. no
no
Scatter radiation does not affect: a. visibility of spatial resolution b. image contrast c. occupational dose d. recorded spatial resolution
recorded spatial resolution
Radiographic contrast consists of a combination of: a. subject contrast and scattering b. subject contrast and film contrast c. film contrast and grid contrast d. density and mAs
subject contrast and film contrast