Radiographic Image Quality - Chapter 10 Evolve

In a particular radiographic examination, the SID is 100 cm and the SOD is 86 cm. The image size-to-object size ratio is approximately: 0.86:1 1.12:1 1.16:1 2.14:1 3:1

1.16:1

If the SID is 100 cm and an object is place 20 cm from the image receptor, what is the magnification factor (MF) ? 0.8 1.0 1.25 1.4 1.6

1.25

Which, when increased, will increase radiographic image quality? (1) Noise (2) Spatial resolution (3) Contrast resolution 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

2 and 3 only Increased spatial and contrast resolution will both increase radiographic image quality.

In magnification radiography, when the object is placed equidistant between the source and the image receptor, the size of the image will be: 1.33 times object size 2.0 times object size Four times object size One-half the object size The same size as the object

2.0 times object size

If other factors remain constant, which of the following would result in the highest optical density ? 100 mA, 750 ms, 90 cm SID 200 mA, 500 ms, 90 cm SID 300 mA, 300 ms, 100 cm SID 400 mA, 200 ms, 100 cm SID 500 mA, 100 ms, 100 cm SID

200 mA, 500 ms, 90 cm SID

Which technique factors should result in the highest contrast ? 100 mA, 500 ms, 60 kVp, no grid 200 mA, 750 ms, 50 kVp, 16:1 grid 400 mA, 100 ms, 60 kVp, no grid 600 mA, 700 ms, 70 kVp, 8:1 grid 800 mA, 200 ms, 80 kVp, 8:1 grid

200 mA, 750 ms, 50 kVp, 16:1 grid

A 20 cm object is radiographed at 40 cm from the focal spot, and the SID is 60 cm. The size of the image will be: 30 cm 40 cm 50 cm 60 cm 70 cm

30 cm

A radiograph was made using these factors: 200mA, 300ms, 70kVp, 100cm SID. A mobile radiograph is then conducted at 80 cm. To maintain the same optical density, approximately what mAs should be selected ? 15 mAs 20 mAs 28 mAs 38 mAs 48 mAs

38 mAs

Which technique factors should result in the highest optical density ? 100 mA, 500 ms, 60 kVp, no grid 200 mA, 750 ms, 50 kVp, 16:1 grid 400 mA, 100 ms, 60 kVp, no grid 600 mA, 700 ms, 70 kVp, 8:1 grid 800 mA, 200 ms, 80 kVp, 8:1 grid

600 mA, 700 ms, 70 kVp, 8:1 grid

Which technique factors should result in the highest patient dose ? 100 mA, 500 ms, 60 kVp, no grid 200 mA, 750 ms, 50 kVp, 16:1 grid 400 mA, 100 ms, 60 kVp, no grid 600 mA, 700 ms, 70 kVp, 8:1 grid 800 mA, 200 ms, 80 kVp, 8:1 grid

600 mA, 700 ms, 70 kVp, 8:1 grid

In a radiographic examination of the lumbar spine, which of the following techniques would result in greatest exposure to the patient ? 70 kVp 200 mAs 80 kVp 100 mAs 95 kVp 50 mAs 110 kVp 25 mAs 120 kVp 25 mAs

70 kVp 200 mAs

Assume that the usual exposure time for a lateral cervical spine radiograph at 100 cm SID is 100 ms. At an SID of 90 cm, all other factors remaining the same, the correct exposure time would be: 10 ms 25 ms 50 ms 80 ms 180 ms

80 ms

Which technique factors should result in the greatest latitude ? 100 mA, 500 ms, 60 kVp, no grid 200 mA, 750 ms, 50 kVp, 16:1 grid 400 mA, 100 ms, 60 kVp, no grid 600 mA, 700 ms, 70 kVp, 8:1 grid 800 mA, 200 ms, 80 kVp, 8:1 grid

800 mA, 200 ms, 80 kVp, 8:1 grid

A decrease in noise will _________ image quality. increase decrease have no effect on

A decrease in noise will increase image quality.

The heel effect should be considered when radiographing all of these body parts except the: Femur Chest Hand AP lumbar spine

A radiographic exam of the hand cannot utilize the heel effect.

Which of the following conditions contributes least to image distortion ? A thick object at a short SID A thin object at a long SID Angling the central ray Object position Off-axis imaging

A thin object at a long SID

Which term is defined as the characteristic of a subject that affects subject contrast? Motion blur Shape distortion Absorption blur Structure mottle

Absorption blur is the characteristic of a subject that affects subject contrast.

Which affect the quality of a radiographic image? (1) Patient positioning (2) Image receptors (3) Selection of technique factors 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

All of these affect image quality.

Which of these radiographic examinations should use the heel effect? (1) AP thoracic spine (2) Humerus (3) Abdomen 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

All of these anatomic parts, and others, should use the heel effect during imaging exams.

What is the effect if kVp is increased? (1) Longer gray scale (2) Wider exposure latitude (3) Decreased patient dose 1 and 2 only 1 and 3 only 2 and 3 only 1, 2, and 3

An increase in kVp would increase the gray scale and exposure latitude, and patient dose would decrease.

When radiographic technique factors are adjusted to provide an acceptable image and then filtration is added to the x-ray tube, which of the following will increase ? Average energy of the x-ray beam Optical density Patient dose Radiographic contrast Spatial resolution

Average energy of the x-ray beam

Distortion primarily occurs: Because subject anatomy is inclined Because subject anatomy is thick rather than thin When improper kVp was selected When subject anatomy is flat When subject anatomy lies parallel to the image receptor

Because subject anatomy is inclined

Distortion: Can be corrected by proper patient positioning Is controlled by focal-spot size Never accompanies magnification Occurs only lateral to the central axis of the x-ray beam Occurs only when the image is inclined

Can be corrected by proper patient positioning

Which of the following is not one of the geometric factors that affect radiographic quality ? Collimation Distortion Focal-spot size Magnification SID

Collimation

Use of contrast media principally affects which of the following ? Blur Contrast resolution Mass density Optical density Speed

Contrast resolution

The shape, position, and thickness of an object affect the: Focal-spot blur Heel effect Subject contrast Distortion

Distortion is affected by object shape, object position, and object thickness.

In the selection of technique factors for optimum radiographic image quality, which of the following is true? Low kVp provides the widest exposure latitude. Fast-speed image receptors provide the best spatial resolution. High mAs provides the best contrast scale. Exposure time should be set as short as possible.

Exposure time should be set as short as possible to minimize motion blur.

Fast image receptors have ____ noise and ____ spatial and contrast resolution. high-high high-low low-low low-high

Fast IRs have high noise and low spatial and contrast resolution.

What is the effect on radiographic image quality if focal-spot size is increased? Increased focal-spot blur Decreased focal-spot blur Increased absorption blur Decreased absorption blur

Focal-spot blur increases as focal-spot size is increased.

The magnification factor is not dependent on: Focal-spot size OID SOD SSD SID

Focal-spot size

Which of the following is most often influenced by focal-spot size ? Absorption blur Contrast resolution Geometric blur Motion blur Patient dose

Geometric blur

If a radiograph technique designed for an 8:1 grid is changed to accommodate a 10:1 grid: Grayscale contrast will become longer. Grayscale contrast will become shorter. There will be no change in contrast resolution. There will be no change in grayscale contrast. There will be no change in x-ray tube capacity.

Grayscale contrast will become shorter.

If a radiographic technique calling for 100 mA at 100 ms is changed to 50 mA at 2000ms: Grayscale contrast will become longer. Grayscale contrast will become shorter. There will be no change in grayscale contrast. There will be no change in exposed time. There will be no change in x-ray tube capacity.

Grayscale contrast will become shorter.

When radiographic technique factors are adjusted to obtain an acceptable image, patient dose will increase as which of the following increases ? Film speed Grid ratio SID SOD SSD

Grid ratio

Magnification is reduced by which of the following ? Increasing kVp Increasing screen speed Increasing SID and OID Increasing SID and decreasing OID Reducing focal-spot size

Increasing SID and decreasing OID

Radiographic contrast is increased by which of the following ? Increasing grid ratio Raising kVp Reducing the air gap Reducing the heel effect Using a slower film

Increasing grid ratio

A longer grayscale on a radiograph can be obtained by doing which of the following ? Increasing kVp Increasing mAs Reducing kVp Reducing mAs Using a larger focal spot

Increasing kVp

Large differences in the effective atomic number of adjacent tissues result in: High subject contrast Low subject contrast Long gray scale Decreased subject contrast

Large differences in the effective atomic number of adjacent tissues result in high subject contrast.

High spatial and contrast resolution require _____ noise and _____ image receptors. high-fast low-fast high-slow low-slow

Low noise and slow IRs provide the best spatial and contrast resolution.

Distortion of an x-ray image results from unequal: Exposure of the object Focal spot Heel effect Magnification SID

Magnification

The factors that affect magnification are: OID and SOD OID and SID Focal-spot size and OID SOD and focal-spot size

Magnification is affected by SID and OID.

Which will increase radiographic magnification? Decrease in patient thickness Increase in OID Decrease in focal-spot size Decrease in SID

Magnification is increased if OID is increased.

A radiograph that exhibits a long grayscale contrast has which of the following features ? Few shades of gray that have great differences Few shades of gray that have minimal differences Good spatial resolution Many shades of gray that have great differences Many shades of gray that have minimal differences

Many shades of gray that have minimal differences

When the mAs is adjusted to provide constant optical density after an increase in kVp: Absorption blur is reduced Geometric blur is reduced Latitude is reduced Motion blur is reduced if the same mA is used Spatial resolution will improve

Motion blur is reduced if the same mA is used

Movement of the patient or x-ray tube causes: OID and SOD OID and SID Focal-spot size and OID Motion blur

Motion blur is the type of blur caused by patient and/or tube motion.

Which term is defined as a grainy or uneven appearance of an image caused by an insufficient number of primary x-rays? Sensitivity Structure mottle Noise Film graininess

Noise is defined as a grainy or uneven appearance of an image caused by an insufficient number of primary x-rays.

Image magnification increases with increasing: Image size Object size OID SID SOD

OID

The magnification factor increases with increasing: Focal-spot size OID SID SOD SSD SOB

OID

Reducing field size through proper collimation usually results in improved (select all that apply): Blur Contrast resolution Magnification Patient dose Spatial resolution

Patient dose , Contrast resolution

To obtain minimum magnification, one should do which of the following ? Make sure the object is positioned on the central axis. Position the anatomy close to the image. Select a short SID. Select a short SSD. Use maximum collimation.

Position the anatomy close to the image.

To minimize magnification, one should do which of the following ? Position the object as close to the image receptor as is practical. Position the x-ray tube as close to the patient as is practical. Use high kVp, low mAs. Use the large focal spot. Use the small focal spot.

Position the object as close to the image receptor as is practical.

To reduce magnification, one should do which of the following ? Reduce OID Reduce SID Reduce SSD Use the small focal spot Use tighter collimation

Reduce OID

An anteroposterior examination of the abdomen is taken at 80 kVp, 50 mAs, and 100 cm SID. If the scale of contrast is to be shortened, the radiologic technologist must do which of the following ? Increase both mAs and kVp Reduce both mAs and kVp Reduce kVp and increase mAs Reduce mAs and increase kVp Shorten the SID

Reduce kVp and increase mAs

Geometric blur can be reduced by which of the following ? Improving film-screen contact Increasing processing time or temperature Increasing SID and OID Increasing SSD and OID Reducing focal-spot size

Reducing focal-spot size

A foreshortened image: Can be corrected by increasing kVp and reducing mAs Can be corrected by reducing kVp and increasing mAs Can be corrected by reducing SID Can never be smaller than the object Results from an inclined object

Results from an inclined object

The ability of an image receptor to respond to x-rays defines: Sensitivity Spatial resolution Quantum mottle Film graininess

Sensitivity is the ability of an image receptor to respond to x-rays.

Image magnification can be reduced with the use of which of the following ? A cone Increased filtration Shorter OID Shorter SID Shorter SSD

Shorter OID

Which speed of image receptors provides the best resolution and low noise? Fast Slow IR speed does not affect these factors.

Slow-speed IRs provide the best spatial and contrast resolution with low noise.

Small differences in the effective atomic number of adjacent tissues results in: High subject contrast Low subject contrast Short gray scale Increased subject contrast

Small differences in the effective atomic number of adjacent tissues results in low subject contrast.

Which term is applied to the noise caused by the distribution of the phosphors in an intensifying screen? Structure mottle Quantum mottle Film graininess Screen graininess

Structure mottle is the noise caused by the distribution of the phosphorus in an intensifying screen.

When an object is present to one side of the central axis of the x-ray beam (select all that apply): Distortion will disappear. Subject contrast will remain unchanged. The magnification factor will be larger. The magnification factor will be smaller. The magnification factor will remain unchanged.

Subject contrast will remain unchanged, The magnification factor will remain unchanged.

The blurred region on the radiograph over which the technologist has little control is: Shape distortion Magnification Focal-spot blur Absorption blur

The blurred region on the radiograph over which the technologist has little control is focal-spot blur.

All are subject factors that affect radiographic image quality except: Patient thickness Object shape Heel effect kVp

The heel effect is not a subject factor.

The only factor that affects subject contrast that is under radiographer control is: kVp SID Patient thickness Object shape

The only factor that affects subject contrast that is under radiographer control is kVp.

The type of distortion caused by elongation or foreshortening is: Shape distortion Magnification Focal-spot blur Absorption blur

The type of distortion caused by elongation or foreshortening is shape distortion.

The formula effective focal spot x OID ÷ SID is used to calculate the amount of: Focal-spot blur Magnification Shape distortion Heel effect

This formula is used to calculate focal-spot blur.

The formula SID ÷ SOD is used to calculate: Focal-spot blur Magnification factor Shape distortion Heel effect

This formula is used to calculate magnification factor.

Which of the following is the function of optimizing contrast ? To control detail sharpness To control quantum mottle To determine optical density To improve spatial resolution To make detail visible

To make detail visible

A radiographic technique that would ensure visibility of detail for a cervical spine is: Increasing the OID Reducing the SID Reducing the SSD Selecting the large focal spot Using a beam restriction device

Using a beam restriction device

For a mobile abdominal radiographic examination, radiographic contrast can be increased by doing which of the following ? Increasing kVp and decreasing mAs Increasing the OID Increasing the SID Using a faster image receptor Using a high-ratio grid

Using a high-ratio grid

Focal-spot blur can be reduced by which of the following ? Increasing kVp Increasing mAs Increasing OID Reducing SOD Using the small focal spot

Using the small focal spot

Which of the following does not affect image blur ? Focal-spot size kVp OID SID SOD

kVp

With other factors constant, optical density will increase with increasing: Focal-spot size Grid ratio mAs SID SSD

mAs