Radiographic Sensitivity (3)

Question 1

Radiographic Sensitivity

Answer 1

A measure of the quality of an image (smallest defect that can be detected)

Question 2

What are Image Quality Indicators (IQI) or Pentameters (pennies)?

Answer 2

Indicate the quality of a radiograph.

• Plaque type ASTM (American Society for Testing Materials)
• Wire type DIN (Deutsches Institut fur Normung [German Institute for Standardization])

Question 3

Variables for Radiographic Sensitivity

Answer 3

Contrast and Definition of an image.

Sensitivity is dependent on these effects combined.

Question 4

Radiographic Contrast

Answer 4

• Radiographic Density
• Measure of the degree of film darkening
• White, Grey, Black is better/more contrasted than light grey, mid grey, dark grey
• Two factors: Subject and Film

Question 5

Subject Factors in Radiographic Contrast

Answer 5

Factors that affect contrast pertaining to the actual radiation itself

• Absorption differences in specimen
• Energy or primary radiation
• Scattered Radiation

Question 6

Film Factors of Radiographic Contrast

Answer 6

Factors impacted by film.

• Type of film (grain size)
• Development technique
• use of screens

Question 7

Subject Contrast

Answer 7

Ratio of radiation intensities transmitted through different areas of the specimen.

• Absorption differences
• Larger the difference in density, larger the difference in contrast
• Low Kv in primary radiation results in a radiograph with high-contrast
• Intensity is due to secondary Scattering

Question 8

Radiographic Definition

Answer 8

How abrupt of a change there is between different densities

- Ombre vs solid-to-solid

Question 9

Geometric Factors that impact Radiographic Definition

Answer 9

• source size
• source-to-film distance
• specimen-to-film distance
• abruptness of thickness change in specimen
• specimen movement

Question 10

Film Factors that impact Radiographic Definition

Answer 10

• Type of film (grain size)
• Development technique
• use of screens
• energy of primary radiation