radiographic quality Flashcards
(69 cards)
1
Q
- A window into the human body
- Formed by the imaging modalities that use various forms of radiation & energy
to open the body to visualization
A
medical image
2
Q
- Refers to the fidelity with which the anatomical structure that is under
examination is imaged
on the
radiograph.
A
Radiographic Quality (Image Quality)
3
Q
degree of exactness
A
fidelity
4
Q
ability to image two separate objects and visually distinguish one from the other.
A
resolution
5
Q
refers to the ability to image small objects that have high subject contrast such as a bone-soft tissue interface, a breast microcalcification, or a calcified lung nodule.
A
spatial resolution
6
Q
ability to distinguish anatomical structures of similar subject contrast such as liver-spleen and gray matter-white matter. The actual size of objects that can be imaged is always smaller under conditions of high subject contrast than under conditions of low subject contrast.
A
contrast resolution
7
Q
random fluctuation in the Optical Density of the image.
A
noise
8
Q
FOUR COMPONENTS OF RADIOGRAPHIC NOISE:
A
film graininess
structure mottle
quantum mottle
scatter radiation
9
Q
- refers to the distribution in size and space of silver halide grains in the emulsion.
- Always present in radiographic film (exposed)
- Silver halide crystals
A
Film Graininess
10
Q
- is similar to film graininess, however, it refers to the phosphor of the radiographic intensifying screen.
- Phosphor crystals
A
Structure Mottle
11
Q
- is a principal contributor to radiographic noise in man radiographic imaging procedures.
- refers to the random nature by which
x-rays interact with the image receptor - Principal contributor to radiographic
noise
A
Quantum Mottle
12
Q
pocket of energy
A
quanta
13
Q
- this is x-ray radiation that interacts with atoms in the patient’s body and is deflected from its original path.
- Secondary radiation
A
Scatter Radiation
14
Q
- refers to the sensitivity of an intensifying screen to X-rays. It essentially reflects how much X-ray radiation is needed to create a bright enough image on the X-ray film.
- It influences the radiographic resolution
A
SPEED
15
Q
- These screens have a higher sensitivity to X-rays.
A
high-speed screens
16
Q
- They require a lower X-ray dose to create a bright enough image on the film. This is crucial to minimize radiation exposure to patients, especially for sensitive individuals or frequent X-ray examinations.
A
high-speed screens
17
Q
- These screens have a lower sensitivity to X-rays.
A
low-speed screens
18
Q
- They require a higher X-ray dose to achieve the same image brightness as high-speed screens.
A
low-speed screens
19
Q
They often produce sharper images with finer details due to less light scattering within the phosphor layer.
A
low-speed screens
20
Q
They may have slightly reduced image sharpness compared to slower screens
A
high-speed screens
21
Q
PRINCIPAL FACTORS THAT MAY AFFECT RADIOGRAPHIC QUALITY
A
film factors, geographic factors, subject factors
22
Q
Film Factors
(characteristic curve)
A
- Density
- Contrast
- Speed
- Latitude
23
Q
Film factors (Processing)
A
- Time
- Temperature
24
Q
Geometric Factors
A
- Distortion
- Magnification
- Blur
25
Subject Factors
(contrast)
- Thickness
- Density
- Atomic number.
- Motion
26
characteristic curve
toe region
straight-line region
shoulder region
27
initial slowly increasing portion of the curve, the film has a low sensitivity to X-ray exposures, resulting in initial changes in density.
toe region
28
middle portion of the curve with the steepest slope. This is the ideal exposure range where the film demonstrates a linear relationship between exposure and density, allowing for good contrast in the final film.
straight-line region
29
final portion of the curve where the density increases rapidly with minimal further increase in exposure. This portion represents the overexposure of the film, resulting in a loss of detail in the brighter areas of the image.
shoulder region
30
Photographic Quality
- Density
- Contrast
31
Geometric Quality
- Detail
- Distortion
32
- Regarded as the general blackening of the radiograph
- It is also the accumulation of black metallic silver after subsequent processing.
- It represents how attenuated by the radiation was the anatomical part.
radiographic density
33
Five major groups of tissue density
aerated tissue
fatty tissue
bone
metal
water
34
● Aerated tissue (filled with air)
dark/black
35
● Fatty tissue
- Slightly gray
36
● Water
- Gray
37
bone
white
38
metal
white
39
measurement of the quantity of radiation absorbed by the intensifying screen, converted to light and transmitted to the film.
radiographic density
40
- difference in density between two structures
- The presence of _ means that different density levels are visible on the radiograph.
radiographic contrast
41
Is the result of attenuation and the differential absorption of tissue.
radiographic contrast
42
types of contrast
subject contrast/film contrast
43
SUBJECT / TISSUE CONTRAST
(influenced by the ff.)
1. Patient size
2. Tissue type
3. Health Status
4. Attenuation properties of tissue.
44
- When tissue type is very dense
- X-rays have a difficult time penetrating.
- High attenuation rate
High differential absorption
45
- Soft tissue
- Low attenuation properties.
Low differential absorption
46
refers to the number of different densities present on the radiograph
scale
47
- High kVp
- “Lower-contrast”
- Preferred in lung
examinations
Long Scale Contrast
48
- “High-contrast”
- Low kVp
- Fewer density
Short Scale contrast
49
- Mixture of black, gray, and white.
Moderate Contrast
50
- refers to the range of material thickness that can be imaged. This means that more areas of different thicknesses will be visible in the image
- range of exposure techniques that will produce an acceptable image
- Inversely proportional to contrast
latitude
51
determined by the inherent contrast of the film.
film latitude
52
film response to variations in exposure.
film contrast
53
Refers to the range of exposure factors (mAs/kV) that will produce an acceptable film.
exposure latitude
54
wide latitude or low contrast film.
high kv
55
narrow latitude or high contrast film.
low kv
56
- It is the actual or visible detail of the part of interest recorded in the film.
- Refers to how well one can see small structures on the radiograph
recorded detail
57
sharpness of detail
definition
58
play a significant role in determining the quality of a radiographic image.
They influence factors like magnification, distortion, and sharpness, all of which can impact the diagnostic value of the image.
geometric factors
59
geometric factors
• Source-to-Image Receptor Distance (SID)
• Object-to-Image Receptor Distance (OID)
• Angulation
• Collimation
• Focal spot size
60
misinterpretation of size and/or shape of the object
distortion
61
two types of distortion
- Size Distortion (Magnification)
- Shape Distortion (Magnification)
62
- To reduce magnification, place the object as near the film as possible.
- Direct magnification
- Directly proportional to magnification
Object-to-Image Receptor (OID)
63
Inversely proportional to magnification
Source-to-Image Receptor Distance (SID
64
indicates the amount of magnification of the object.
magnification factor
65
• Occurs whenever the OID is greater than zero
• All objects on the radiograph are larger than the actual size.
• It is caused by the divergence (spreading out) of the x-ray beam as it moves away from the target (x-ray tube ) where the x-ray are produced
• _ of an object positioned off the central rays is the same as that of an object on the central ray if th objects are in the same plane.
magnification
66
Size of the area on the anode where x-rays are producing
focal spot size
67
SHAPE DISTORTION
Factors:
• Tube Angulation
• Image Receptor Angulation
• Part Angulation
68
- When a structure appears shorter and thicker than its actual shape on the X-ray image.
FORESHORTENING
69
When a structure appears longer and thinner than its actual shape on the X-ray image.
ELONGATION
