Film (2,3)

Question 1

Class depends on?

Answer 1

• film speed
• size of silver bromide and silver chloride grains
• contrast

Question 2

Contrast

Answer 2

Films ability to show density differences

- (high or low)

Question 3

Classes

Answer 3

Type I

• Type II
• Type III
• Type IV
• Speed is slowest at Type I
• Grain is finest at Type I
• Contrast is highest at Type I

Question 4

What are radiographic films made of?

Answer 4

An emulsion of gelatin and radiation sensitive silver halide crystals (silver bromide or silver chloride) that coat both sides of the base and layers about 0.0005in thick.

Question 5

X-Ray Films are sensitive to what?

Answer 5

Light

Question 6

What happens when developing Radiographic Film?

Answer 6

Ionization disturbs the atomic structure silver bromide in the film causing atoms to enter chemical reactions with one-another producing an image.

Question 7

Lead Screens

Answer 7

Scattered Photons create a loss of contrast and definition. Exposures above 150Kv place the film between two thin sheets of lead foil screens.

Question 8

Lead Foil Screens

Answer 8

• Two thin sheets of lead compound evenly coated on a paper backing - essential in radiographic and gamma ray film
• increase the films “photographic action”

Question 9

What does Lead do to film?

Answer 9

• Lead emits electrons and secondary radiation under the action of X/Gamma rays
• shorter exposure time
• Absorb large portion of scattered radiation intensifying primary radiation (contrast + definition)

Question 10

Fluorescent Screens

Answer 10

Incident radiation causes these screens to give off light to help expose film

• light produced is in all directions = lower definition
• medical radiography, low Kv
• NOT FOR GAMMA RAYS (RULE)
• Thick specimens