Xray - Outcome 5 Flashcards
Automatic Processor - for Film
Automatic processor units can improve the efficiency and consistency of resulting radiographic images on traditional x-ray film. The radiographic images are transported through solutions, to a wash, and then finished at a dryer. A series of rollers are used to carry the films along and squeegee the solutions from the films between solutions. This reduces the contamination of one solution with anothe
How long does an automatic processor take?
Using an automatic unit, the total processing time, from developing to receiving the dried films, usually takes from 4 to 6 minutes depending on the manufacturer. This is achieved by using special processing chemistry at a higher temperature (80° to 95° F) and an internal dryer
Daylight loader - Automatic Processing
The automatic processing unit may be used in a traditional darkroom setting or in daylight if a daylight loader is attached to the unit. The daylight loader allows the films to be unwrapped and fed into the processor outside of a darkroom
Maintanence of Automatic Processors
If maintained according to the manufacturer’s instructions, automatic processors will produce consistent, quality radiographs. Maintenance includes checking solution levels, replenishment of solutions, thorough cleaning of tanks and rollers on a regular maintenance schedule as well as the replacement of solutions on a regular basis. Cleaning films should be run through the processor at the beginning of each day to remove any contaminants on the rollers. The chemistry used in automatic processors is different from manual processing solutions. Only chemistry specifically designed for automatic processors can be used because it is manufactured to perform at high temperatures. A care and maintenance schedule for developing equipment is one of the contributors to quality assurance
There are two processing solutions involved in processing conventional dental x-ray films. They are:
- Developer
- Fixer
When a conventional X-ray film enters an automatic processor it will go through the following stages:
- Developing the developer solution
- Fixing the fixer solution
- Washing in the water bath
- Drying
2 Types of Silver Haide used in the emulsion of dental film
- Silver Bromide
- Silver Iodide
When silver halide grains are exposed to light or xrays they…
..they store energy from the radiation. Various areas on the film receive more or less radiation depending on the density of the tissue being exposed (differential absorption) and therefore, exposed films have areas in which silver halide crystals contain various levels of stored energy. The pattern formed by the energized and non-energized crystals creates the latent image within the emulsion
The developer permeates the..
…the gelatin and reacts with all the silver halide crystals . The energized crystals are easily excited and react quickly with the developing chemicals.
The silver halide separates into..
….into bromide (or iodide) and metallic silver
Metallic Silver produces what on a developed radiograph?
Black areas on a developed radiograph. This black metallic silver is deposited on the film.
Silver halide crystals that did not receive x-radiation gives us…
Silver halide crystals that did not receive x- x-radiation and are not energized, do not react with the developer and are washed away. The corresponding area on the film will be white
Density of a radiograph
The number of X-rays used to expose the film determines the overall darkness of the processed radiograph. This degree of blackness is referred to as the density of the radiograph. An over-exposed film will appear to be too dark while an under-exposed film will appear too light.
Contrast of a radiograph
Contrast is the difference in densities of adjacent shadows recorded on the film. The greater the difference in densities between two adjacent structures, the greater the image contrast.
Long-Scale Contrast
An increased range of grays between the blacks and whites on a radiograph. Higher kilovoltage increases this range.
Short-Scale Contrast
A reduced range of grays between the blacks and whites on a radiograph.
Fixing in the Fixer Solution
The fixer dissolves and removes the unexposed silver halide crystals from the film emulsion which clears the film so that the black or darker images become more perceptible. The fixer also hardens the emulsion, allowing you to handle the film.
Washing in the Water Bath
After the fixer, the film is fed into the water bath to remove all the agents used to process the film.
Drying
An internal dryer found in the automatic processor dries the films after the washing stage before the films are expelled out of the automatic processor and ready for viewing
In the past, radiographs could be processed in two ways:
- Time-temperature method in a darkroom (manual)
- Automatic processing unit (automatic/mechanical)
However, as times change, techniques change. The manual method of processing conventional X-ray film has become obsolete. However, the use of automatic processing units, whether in a dark room or as day-light loaders, is still common.
The Dark Room
Dark rooms are designed to filter out visible light, except for safelights. The room must be completely dark because conventional x-ray films are sensitive to light
Errors in the Darkroom
Errors in the darkroom can easily ruin a good film, making it necessary to retake the films resulting in loss of time and increased radiation exposure to the patient and loss of tim
Darkroom Responsibility
The darkroom is one of the areas in a dental office for which the dental auxiliary has complete responsibility. In addition to processing films, the auxiliary must keep the darkroom clean, change solutions regularly, and keep accurate records of the radiographs processed. Only through meticulous attention to detail can proper dark room technique be maintained. It is important to realize that the processing of film is a vital link in the production of the diagnostic radiograph.
Latent Image
Radiographs, having been exposed in the patient’s mouth, contain a “latent image”. Processing the film makes this latent (or invisible) image visible and permanent
The steps in the processing procedure of traditional film are…
developing, rinsing, fixing, washing and drying
Copies or duplicates of radiographs may be required for:
- Sending to insurance companies for pre-authorization of treatment
- Referring the patient to a specialist for treatment
- Transferring records for patients who are changing dentists
How to make duplicate films
This can be accomplished either by using a film packet containing two films instead of one or by duplicating the radiographs. Duplicating radiographs requires a film duplicator and duplicating film. The duplicator provides a light source (usually ultraviolet) to expose the film. Duplicating film only has emulsion on one side. In addition, the concept of exposure is different. The longer the film is exposed to the light source, the lighter (less dense) the duplicate radiograph will appear
Duplicating films take place in a darkroom under safelight conditions. The films are placed on the duplicator and the duplicating film is placed over the radiographs with the emulsion side contacting the radiographs. The radiographs and the duplicating film must lie flush against one another. The duplicator is then activated for the time specified in the manufacturer’s directions. The duplicating film is then removed and processed in the normal procedure
Advantages of PSP
The processing of PSP plates requires only an electronic processor and a computer – no chemicals. This reduces the need to purchase and store materials as the plates may be reused, the images on the plates are erased after processing, and the images are recorded and saved onto a computer
The procedure for processing a phosphor plate is as follows:
- An image is recorded by exposing the phosphor-coating on the phosphor plates.
- The phosphor plates are fed through an electronic processor (scanner) where a laser will scan the plate and transfer the image onto a computer screen.
- The processor can be set to save or erase the image.
- The image can be manipulated and viewed.
As a Registered Dental Assistant, you will be required to assess your films for quality and problem-solve any errors. Areas to be assessed are specific to:
Film placement
Horizontal/vertical angulation
Density/contrast
Operator errors
Handling/mounting
Errors in Processing: Stained Film
Any fluid can stain a dental X-ray film.
Errors in Processing: Stained Film - Clear Spots
a. Clear Spots - If drops of water are left in contact with the film, the emulsion will dissolve and leave a clear spot.
Errors in Processing: Stained Film - White Spots
b. White Spots - Usually caused by allowing the film to come into contact with the fixing solution before developing. These areas are lighter in appearance because the silver halide reduction to black metallic silver was blocked by the fixing solution.
Errors in Processing: Stained Film - Black Spots
c. Black Spots - Caused by premature contact with the developing solution. When the film is placed in the developer for normal development, the area that has already contacted the developing solution becomes over-developed causing a dark spot or streak.
Errors in Processing: Stained Film - Opaque Spots
d. Opaque Spots - These areas are caused by one film clinging to another or the side of the tank during the fixing process. To prevent this, always agitate the films when placing them in the solution and make sure that they are not touching another film or the side of the tank. This can also result when films are processed too close together in an automatic processing unit.
Errors in Processing: Stained Film - Brown Stain
e. Brown Stain - Usually caused by “old” developer or insufficient time in fixer and wash baths.
Errors in Processing: Stained Film - Gray Image
f. Gray Image - The image appears grey or washed out. This is usually caused by contaminated solutions or lack of replenishment.
Errors in Processing: Stained Film - Fluoride Artifact
g. Fluoride Artifact -Fingers contaminated with fluoride solution will leave black fingerprint stains on the film.
Errors in Processing: Dark Films
There are many causes of dark films:
exposure to light
overdevelopment (too long)
overly high developer concentration
temperature too high
Errors in Processing: Light Films
A radiograph that is too light and lacks density may be caused by:
underdevelopment (not long enough)
cold processing solution
weak processing solution (too old, under replenishment)
solutions not being stirred
Errors in Processing: Partial Image
The film will have a straight, clear portion. This is caused by the failure of the processing solutions to cover the film. Check the level of the solutions before beginning to process.
Errors in Processing: Scratched Film
Scratches are caused by sharp or pointed objects and fingernails (crescent-shaped marks).
Errors in Processing: Static
A “tree-like” artifact appears on the film. This is caused by the production of static electricity while processing.
Errors in Processing: Torn Film
Usually results from removing the film from the packet too hastily.
Errors in Processing: Reticulation
The film appears “pitted.” This is caused by sudden temperature changes between processing solutions and wash water.
Errors in Processing: Cathedral Effect
The film has a mottled appearance caused by a very short development time (30 seconds).
Errors in Processing: Fogged Films
The overall appearance of a fogged film is also dark. The film lacks density, and the images lack definition and appear as though they are being viewed through fog. Fogging is usually due to an excessive amount of light reaching the film from an improper safe light, from light leaks around the dark room door, or from turning on a white light before the film is adequately fixed. The out-dated film has a degree of fog imparted to it.
Film Errors can be reduced by..
Film errors can be reduced by establishing a quality assurance program and by carefully monitoring image production. Unusual artifacts or problems should be documented as a guide for correction and improvement
