Radiographic image: Radiographic film Flashcards
What is a remnant beam also known as?
Exit-ray beam
What is a remnant beam?
exits the tube and enters the patient
What are the 2 parts of film design? Which part is where the image is formed?
- base and emulsion
- emulsion
What is the film base made of? and what does it provide?
- polyester
- rigidity and dimensional stability
What is emulsion made of?
-gelatin and contains Silver Halide Crystals (98% silver bromide and 2% iodide)
What are SHC composed of?
-high atomic number thus more readily X-rays and emit light photons from intensifying screens
What is it when X-rays and light interact via PE and Compton scatter interacts with SHC?
latent image
What is a contaminated emulsion by silver sulfide located in the center of Silver Bromide?
sensitivity speck/centre
What is the sensitivity speck responsible for?
-attracting and trapping an ion of silver and the electron producing a latent image
What shape are SHC?
-tubular
What is the difference between larger and smaller crystals?
- Larger crystals: develops faster but low contrast
- Smaller crystals: develops slower but high contrast
How does a secondary electron form?
-When X-rays and photons interact with SHC via PE and Compton Scatter
How many silver atoms have most SHC collected and retained in the optimally exposed film?
4-10 silver atoms
True or False: Latent image is invisible
True
Where are screen-films most commonly used?
Within the image receptor and cassette’s intensifying screen
What are direct films used for?
Dentistry
What are Image receptor films coated with?
double emulsion layer
How do you prevent crossover exposure?
adding a dye or crossover control layer to the film base
How long did manual processing take? and what were the steps to get an image?
-1 hour
-soaking the film
immersing it in the developer
-washing it
-drying it
When and who introduced the first automatic processing machine? and how long did it take to manifest image?
- 1942 Pako
- 40min
When and who introduced the roller system?
-1956 Kodak
When and who introduced automatic processing of 45 seconds per step?
-1987 Konica
What is the automatic processing sequence?
Developing - Fixing - Washing - Drying
What happens during the Developing stage? and what are the main components?
- electrons are added to ionic silver to reduce it to metallic silver (e- + Ag+ = Ag).
- hydroquinone and phenidone
