III. Principles of Imaging

Question 1

Image characteristics

Image brightness

Answer 1

Brightness refers to how light or dark an image appears.

Question 2

Image characteristics

Acceptable range

Answer 2

Determined by optimal exposure settings.

Question 3

Image characteristics

Technical factors:
mAs

Answer 3

Affects the total quantity of X-rays.

Question 4

Image characteristics

Technical factors:
kVp

Answer 4

Controls the energy and penetration of X-rays.

Question 5

Image characteristics

Technical factors:
Distance

Answer 5

Source-to-image distance affects brightness.

Question 6

Image characteristics

Technical factors:
Beam limitation

Answer 6

Reduces scatter and improves image quality.

Question 7

Image characteristics

Technical factors:
Patient considerations

Answer 7

Body habitus and condition influence exposure requirements.

Question 8

Image characteristics

Technical factors:
Contrast media

Answer 8

Enhances brightness and visibility of specific tissues.

Question 9

Image contrast

Answer 9

The difference in brightness between adjacent areas in an image.

Question 10

Image contrast

Types:

Long scale

Answer 10

Many shades of gray (low contrast).

Question 11

Image contrast

Types:

Short scale

Answer 11

Few shades of gray (high contrast).

Question 12

Image contrast

Components:

Subject

Answer 12

Determined by differences in tissue density.

Question 13

Image contrast

Components:
Image receptor

Answer 13

Controlled by detector properties.

Question 14

Image contrast

Technical factors:
kVp

Answer 14

Higher kVp reduces contrast, lower kVp increases contrast.

Question 15

Image contrast

Technical factors:
Scattered radiation

Answer 15

Reduces contrast; minimized with collimation.

Question 16

Image contrast

Technical factors:
Filtration

Answer 16

Removes low-energy photons, affecting contrast.

Question 17

Image contrast

Technical factors:
Patient considerations

Answer 17

Tissue composition influences contrast.

Question 18

Image contrast

Technical factors:
Distance

Answer 18

Increased distance reduces scatter and improves contrast.

Question 19

Image contrast

Technical factors:
Contrast media

Answer 19

Improves contrast by enhancing specific structures.

Question 20

Recorded detail

Recorded detail

Answer 20

The sharpness of structural lines in the image.

Question 21

Recorded detail

Geometric unsharpness
a) Focal film distance
b) Object film distance
c) Focal spot

Answer 21

Focal film distance (FFD): Increasing FFD reduces unsharpness.

Object film distance (OFD): Decreasing OFD minimizes unsharpness.

Focal spot size: Smaller focal spots produce sharper images.

Question 22

Recorded detail

Motion unsharpness
a) Voluntary
b) Involuntary

Answer 22

Voluntary motion: Patient movement that can be minimized with proper instructions.

Involuntary motion: Internal movements like heartbeat or breathing, managed with short exposure times.

Question 23

Distortion

Answer 23

A misrepresentation of the size or shape of the object being imaged.

Question 24

Distortion

Types:
Shape Foreshortening

Answer 24

Object appears shorter than it is.

Question 25

# *Distortion* Types: Shape Elongation

Answer 25

Object appears longer than it is.

Question 26

# *Distortion* Size (magnification)

Answer 26

Caused by increased distance between the object and the detector.

Question 27

# *Distortion* Factors: Distance

Answer 27

Source-to-image distance (SID): Greater SID reduces magnification.

Question 28

# *Distortion* Factors: Tube/part (image receptor) relationships

Answer 28

Object-to-image receptor distance (OID): Decreasing OID minimizes distortion.

Question 29

Exposure latitude

Answer 29

The range of exposure that produces acceptable image quality.

Question 30

# *Exposure latitude* Factors: kVp

Answer 30

Higher kVp increases exposure latitude.

Question 31

Image receptor scattered/secondary radiation

Answer 31

Radiation that bounces off the patient or other surfaces, reducing image quality.

Question 32

# *Image receptor scattered/secondary radiation* Interactions

Answer 32

Causes noise and reduces contrast in the image.

Question 33

# *Image receptor scattered/secondary radiation* Factors: kVpf

Answer 33

Higher kVp increases scatter.

Question 34

# *Image receptor scattered/secondary radiation* Factors: Patient considerations

Answer 34

Patient size and body habitus: Larger patients generate more scatter.

Question 35

# *Image receptor scattered/secondary radiation* Factors: Distance

Answer 35

Increasing distance reduces scatter.

Question 36

# *Image receptor scattered/secondary radiation* Factors: Contrast media

Answer 36

Enhances contrast but does not directly reduce scatter.

Question 37

# *Image receptor scattered/secondary radiation* Effects: Patient dosage a) Adult b) Pediatric c) Body habitus

Answer 37

Patient size and body habitus: Larger patients generate more scatter. Patient dose: Increases with scatter

Question 38

# *Image receptor scattered/secondary radiation* Effects: Image quality

Answer 38

Decreases due to reduced contrast.

Question 39

# *Image receptor scattered/secondary radiation* Effects: Occupational exposure

Answer 39

Increases for personnel if proper shielding is not used.