Term Test 2 Flashcards
What does ALARA stand for?
What is the concept?
- As low as reasonably achievable.
- Every possible method of reducing exposure to radiation should be used.
Methods of radiation protection used by the dental radiographer to achieve the ALARA concept.
- Lead Apron
- Thyroid collar
- 16 inch PID should be used as it produces less divergence of the x-ray beam.
- Rectangular PID
- Digital image receptors
- Beam alignment device
Define Maximum Permissible Dose (MPD).
The dose of radiation that the body can endure with little or no injury.
Define Maximum Accumulated Dose (MAD).
- Workers must not exceed an accumulated lifetime radiation dose.
- Formula based on workers age.
Know what the current Maximum Permissible Dose (MPD) for occupationally exposed workers is.
5.0 rem/year
What geometric characteristics influence the diagnostic quality of a dental radiograph.
Sharpness, magnification, and distortion.
What device is used to demonstrate short and long scale contrast.
A stepwedge.
What is the preferable contrast for dental radiography?
A compromise between low contrast and high contrast is preferred.
Know what exposure factor (kVp, mA, time, etc.) has a direct influence on contrast.
Kilovoltage (kV).
What geometric characteristic is affected by focal spot size?
Sharpness.
What are the steps to manual processing?
- Development
- Rinsing
- Fixing
- Washing
- Drying
What are the steps to automatic processing?
- Development
- Fixing
- Washing
- Drying
Why the rinsing step is necessary?
It is needed to remove the developer from the film and stop the development process.
In which step is the film emulsion hardened?
Fixing.
What is the optimal temperature for the developer solution in manual processing?
68 degrees F.
What error can occur if there is a light leak in the darkroom?
Film fogging.
What is the recommended distance a safelight should be placed from the film and working area.
Minimum of 4 feet away.
What factors affect the life of the processing solutions?
- Exposure to air
- Continued use
- Chemical contamination
Why is a replenisher added to the processing solution?
The replenisher compensates for the loss of volume and strength that results from OXIDATION.
How often should the processing tank be cleaned?
Each time the solutions are changed.
Define oxidation.
A chemical reaction that occurs when processing solutions are exposed to air; the chemicals breakdown, resulting in a decreased concentration of solution strength.
Processor housing
Encases all of the component parts of the automatic processor.
Film feed slot
Opening on the outside of the processor housing used to insert unwrapped films into the automatic processor.
Roller film transporter
- System of rollers used to transport the film through the developer, fixer, water and drying compartments.
- Rollers contain a wringing action that removes the excess solution from the emulsion as the film moves from compartment to compartment.
- This eliminates the need for the additional rinse step between the developer and fixer solutions.
Developer compartment
Holds the developer solution.
Fixer compartment
Holds the fixer solution.
Water compartment
- Holds circulating water.
- Washes films after the fixing step.
Drying Chamber
Holds heated air and is used to dry the wet film.
Replenisher pump & replenisher solutions
Used to maintain proper solution concentration and levels automatically in some automatic processors; some require an operator to add necessary replenishing solutions.
Film recovery slot.
Opening on outside of the processor housing where the dry, processed radiograph emerges from the automatic processor.
Underdeveloped film:
Light
Overdeveloped film:
Dark
Reticulation of emulsion:
Cracked
Developer spots:
Dark or black spots
Fixer spots:
White or light spots
Yellow-brown stains:
Yellow-brown color.
Developer Cutoff:
Straight white border
Fixer Cutoff:
Straight black border
Overlapped films:
White or dark areas appear on film where overlapped.
Air bubbles:
White spots
Fingernail artifact:
Black crescent-shaped marks
Fingerprint artifact:
Black fingerprint
Static electricity
Thin, black branching lines.
Scratched film
White lines.
Light leak
Exposed (to light) area appears black
Fogged film
Gray; lack of detail and contrast.
T or F: Film fogging results from improper safelighting.
True
T or F: Yellow-brown stains result from insufficient developing time.
False
T or F: Developer cutoff appears as a straight black boarder across the film.
False
T or F: To avoid static electricity, touch a conductive object before unwrapping a film.
True
T or F: Torn or defective film packets may allow a portion of the film to be exposed to light.
True
How often on average should processing solutions be changed?
every 3-4 weeks
What are the use of dental radiographs.
- Detection of diseases, lesions, and conditions of the teeth and bones that cannot be identified by clinical examination alone.
- Confirming suspected lesions, assisting in the localization of lesions and foreign objects.
Interpersonal skills:
skills that promote good relationships between individuals.
Technical skills:
ability to perform expected tasks.
Verbal communication skills:
- Involves the use of language.
- Speak in a pleasant and relaxed manner.
- Use a soft tone of voice.
Nonverbal communication skills:
- Involves use of body language.
- Maintain direct eye contact.
- Good posture.
Listening skills:
- Receiving and understanding of messages.
- Give undivided attention to the patient when listening.
Facilitation skills:
Interpersonal skills used to ease communication and develop a trusting relationship between the dental professional and the patient.
What may result when a nonverbal message and a verbal message are not consistent. How may the patient react?
He/she may react with apprehension and mistrust.
Who is responsible for answering questions about diagnosis.
The dentist.
Who owns the patient’s radiographs.
All dental records, including the dental images are the property of the dentist.
When can radiographs from a previous dentist be used?
If they are recent and of acceptable diagnostic quality.
Who makes the decision about the number, type and frequency of dental x-rays.
They are determined by the dentist based on individual patient needs.
At what interval should radiographs be taken?
- There is no interval because the prescription of dental radiographs is based on individual needs of the patient.
- A patient prone to tooth decay and with periodontal disease will need x-rays more than a patient who does not have periodontal disease and does not develop decay easily.
When should retakes be avoided?
Always! (I mean it is inevitable that you will have to take some retakes eventually.).
Why is there increased target-receptor distance required in the paralleling technique?
To compensate for image magnification.
What is the relationship of the central ray to the receptor in the paralleling technique?
The central ray of the x-ray beam must be directed perpendicular (at a right angle) to the receptor and the long axis of the tooth.
What is the relationship between the receptor and the long axis of the tooth in the paralleling technique.
Receptor must be positioned parallel to the long axis of the tooth.
Know how the receptor should be placed in the mouth with the paralleling technique.
Away from the tooth towards the midline.
Know how the receptor should be placed in the anterior and posterior exposures.
- Anterior: Vertical
- Posterior: Horizontal
Know the sequence exposure for periapical (PA) receptors. Where should you begin?
Anterior
- Start in the anterior teeth always.
- Begin with maxillary right canine.
- Work right to left.
- Move to mandibular and repeat.
Posterior
- Premolar first always
- Maxillary right premolars then molars.
- Mandibular left premolars then molars.
- Convert device, move to maxillary left premolars and molars.
- Mandibular right premolars and molars.
What are the advantages of the paralleling technique?
- Accuracy
- Simplicity
- Duplication
What is the proper direction of the central ray in the bisecting technique?
The central ray of the x-ray beam must be directed perpendicular (at a right angle) to the imaginary bisector that divides the angle formed by the receptor and the long axis of the tooth.
Describe the distance between the receptor and the tooth in the bisecting technique.
Must be placed against the lingual surface of the tooth.
What is the main advantage of the bisecting technique?
More comfortable for the patient.
What errors can occur with the bisecting technique?
- Image distortion
- Angulation problems (elongation and foreshortening)
What is the primary use for the bite-wing radiograph?
Examine interproximal surfaces of the teeth.
How should the receptor be placed in relationship to the maxillary and mandibular teeth in the bite-wing technique?
- The receptor is placed parallel to the crowns of the maxillary and mandibular teeth.
- Against teeth (lingual of side being x-rayed).
What errors can occur with the bite-wing technique?
Overlapped contacts (due to improper horizontal angulation).
What will the image look like on a radiograph if too much vertical angulation was used?
Foreshortened image.
What error results from incorrect horizontal angulation?
Overlapped contacts.
