X-ray Image processing

Question 1

List down the stages involved in the chemical processing of radiographic images.

Answer 1

1. Development
2. Fixing
3. Washing
4. Drying

Question 2

Development

Answer 2

• The primary purpose is to convert a latent image into a visible image.
• Exposed Silver halide grains in the emulsion layer are reduced to metallic silver. while the unexposed remain unchanged.

Question 3

By products of the development

Answer 3

• AgH is reduced to Ag on continuous development process, causing depletion of electrons in the developer.
• Reaction of developer and atm O2 causes aerial oxidation in developer.
• The Br ions react with hydrogen ions to form hydrobromic acid. which causes the pH to fall

Question 3

Developing agents:

Answer 3

These chemicals, like hydroquinone [C6H4(OH)2] and phenidone[C9H10N2O], are responsible for reducing silver bromide crystals

Question 3

Alkali/ accelerators (e.g., sodium carbonate):

Answer 3

This maintains the developer’s pH level (around 10-11) for optimal activity

Question 3

Preservative (e.g., sodium sulfite):

Answer 3

This slows down the oxidation of the developer, extending its life.

Question 4

Replenisher

Answer 4

A solution that contains the same components as the developer but more concentrated is added to the developer tank to maintain its activity and image quality.

Question 4

Restrainer (e.g., potassium bromide):

Answer 4

This controls the developer’s activity, preventing it from reacting with unexposed silver bromide (which would cause fogging on the film).

Question 5

Define development

Answer 5

• A process of chemical reduction achieved by the developer donating electrons to Ag ions in the exposed AgH grains and converting them to metallic silver.

Question 6

Constituents of the developer solution

Answer 6

• solvent
• Developing agents
• Accelerator
• Buffer
• Restrainer
• Preservatives
• Hardener
• sequestering agents

Question 7

Starter Solution (sometimes referred to as “restrainer bath”):

Answer 7

This solution is sometimes used before the developer, particularly in manual processing. It is essentially a dilute solution containing only the restrainer.

Question 8

Buffers

Answer 8

A chemical compound that maintains the pH of a solution within its limits.

Question 9

Hardeners in the developer

Answer 9

Glutaraldehyde ( organic hardener

Question 10

what can happen if the hardener is not present in the solution.

Answer 10

there might be swelling on the emulsion layer, which can cause unsuccessful transport of the film.

Question 11

Sequestering agents

Answer 11

chemicals that prevent precipitation of insoluble mineral salts that tend to occur in hard water areas.

Question 12

Factors that affecting development.

Answer 12

• pH of developer solution
• Concentration of developing agents
• Temperature of the developer
• Development time

Question 13

Fixation

Answer 13

1. Removal of unexposed silver halide crystals
2. Hardening the emulsion
3. Stopping development
4. clearing the image

Question 14

3. Stopping the development

Answer 14

The fixer can slightly raise the pH of the solution, which helps to stop the developer’s activity and prevent further development of the image.

Question 14

1. Removal of unexposed silver halide crystals

Answer 14

The fixing solution, typically containing sodium thiosulfate, dissolves the unexposed silver halide crystals. This is because the fixer forms a soluble complex with the silver ions present in these unexposed crystals, allowing them to be washed away.

Question 14

2. Hardening of the emulsion

Answer 14

During development, the developer can slightly soften the emulsion.
The fixing solution often contains additional hardening agents that help to counteract the softening effect of the developer and make the emulsion more durable. aluminum sulfite.

Question 15

The constituents of fixer replenisher solution.

Answer 15

*Solvent
*Fixing agent
*Acid
*Hardener
*Buffer
*Preservative
*Anti-sludging agent

Question 16

Solvent

Answer 16

water

Question 17

dichroic fog

Answer 17

a specific type of fog that occurs during development process whereby a thin l layer of metallic silver is redeposited unto the film. the layer may appear red or green.

Question 17

buffer

Answer 17

Important in controlling pH in order to:
a. Prevent sulphurization;
b. Ensure neutralization of developer; and
c. Maintain optimum hardener activity.

sodium acetate

Question 18

anti-sludging agent

Answer 18

Due to the tendency of Al salts used as hardeners producing insoluble Al compounds which may precipitate out to form a sludge and adheres to films and sides of fixing tank, anti-sludging agents are added to reduce formation of the sludge

Question 18

Factors affecting fixation

Answer 18

*Constitution of the fixing solution
*Fixer temperature
*Fixing time

Question 19

3. Washing

Answer 19

• Dissolved salts can crystallize so they have to e washed.
• To prevent gradual development of yellow-brown stain caused by silver complexes and ammonium halides.