Table of Contents
- 1 What chemical stops development of radiographic film during processing?
- 2 Which chemical will neutralize the alkaline developer solution?
- 3 What are the chemicals used in developer solution?
- 4 What chemical prevents the developer from oxidizing and the fixer from decomposing?
- 5 What does the stop bath do?
- 6 How can scatter radiation be prevented?
- 7 What happens when exposed film enters the developer solution?
- 8 How does the density of film change with exposure?
What chemical stops development of radiographic film during processing?
A super concentrated solution added to a processing solution to compensate for the loss of volume and strength that results from oxidation. One of the four basic ingredients of the developer solution; potassium bromide is used to prevent the development of unexposed silver halide crystals; also prevents film fogging.
What is added to the developer to prevent excessive softening of the emulsion and its sticking to processor rollers?
Glutaraldehyde is added as a hardener, particularly in automatic processing to prevent emulsion from softening and sticking to the rollers.
Which chemical will neutralize the alkaline developer solution?
acetic acid
Stop bath is a chemical used for processing black-and-white photographic films, plates, and paper. It is used to neutralize the alkaline developer, thus halting development. Stop bath is commonly a 2% dilution of acetic acid in water, though a 2.5% solution of potassium or sodium metabisulfite works just as well.
What is the main substance contained in the film emulsion covering the film?
X-ray films for general radiography consist of an emulsion-gelatin containing radiation sensitive silver halide crystals, such as silver bromide or silver chloride, and a flexible, transparent, blue-tinted base.
What are the chemicals used in developer solution?
Components
- developer: hydroquinone (for high contrast) + Metol or phenidone (for low contrast)
- alkali: to maintain the pH (at 10-11) of the solution for optimum work of developer.
What causes film emulsion?
The chemicals used in the developing process convert exposed silver bromide (or silver halide) crystals into black metallic silver. It causes the film emulsion to swell so that agents within the developing chemistry can penetrate into all of the exposed silver crystals.
What chemical prevents the developer from oxidizing and the fixer from decomposing?
Sodium sulfite prevents decomposition of the fixing agent.
Which component maintains the chemical balance in both the developer and fixer?
Unit 3
| Question | Answer |
|---|---|
| What component in the fixer removes the undeveloped silver bromide from emulsion? | Fixing agent |
| What component in the fixer stiffens and shrinks the emulsion? | Hardner |
| What component in the fixer maintains chemical balance? | preservative |
| What component in the fixer maintains proper pH | Buffer |
What does the stop bath do?
A stop bath is used to halt the developing process to prevent the picture from getting darker. Fixer then makes the image permanent and light-resistant by dissolving any remaining silver halide salts.
Is stop bath necessary?
You don’t need to use a stop bath when developing film. But using a stop bath is recommended because it immediately arrests development and protects the integrity of your fixer, which requires an acidic solution to function. Stop bath is necessary for most black and white films and papers when using Rapid Fixer.
How can scatter radiation be prevented?
Time: Minimizing the time of radiation exposure will reduce the radiation dose. Distance: Increasing the distance between the patient and the radiation source will reduce exposure by the distance squared. Shielding: Lead or lead-equivalent shielding for X-rays and gamma rays can block and reduce radiation exposure.
What are the components of film emulsion?
Components. Photographic emulsion is a fine suspension of insoluble light-sensitive crystals in a colloid sol, usually consisting of gelatin. The light-sensitive component is one or a mixture of silver halides: silver bromide, chloride and iodide.
What happens when exposed film enters the developer solution?
When an exposed film enters the developer solution, development is not instantaneous. It is a gradual process during which more and more film grains are developed, resulting in increased film density. The development process is terminated by removing the film from the developer and placing it in the fixer.
How is film transferred from developer to Fixer?
Safe-light conditions must be maintained when transferring the film from the developer to the wash tank and then to the fixing tank to avoid fogging. For automatic processing there are “squeegy” rollers that remove the chemicals and thus the film goes from the developer solution straight into the fixer.
How does the density of film change with exposure?
The darkness or density of the film increases as the exposure is increased. This general relationship is shown in the second following figure. The specific relationship between the shades of gray or density and exposure depends on the characteristics of the film emulsion and the processing conditions.
How does film development time affect film sensitivity?
To some extent, increasing development time increases film sensitivity, since less exposure is required to produce a specific film density. In most radiographic film processors, the development time is usually fixed and is approximately 20-25 seconds. However, there are two exceptions.