Radiation Flashcards
What type of waves are X-Rays?
Electromagnetic waves
A form of energy
Travel in a straight line
They are short waves which means they can cause more damage
Invisible
An unaltered X-ray is…
When the beam hits the matter and a little of the beam is absorbed.
A scattered X-ray is…
When the beam hits the atoms of the matter and release their energy in different directions.
A absorbed X-ray is…
When the beam hits the matter and a lot of the beam is absorbed.
What is radiopaque and how does it appear on an X-ray?
Metals (crowns, fillings etc)
Enamel
They appear white on X-rays.
What appears grey on X-rays?
Dentine and bone
What is radiolucent and how does it appear on X-rays?
Appear almost black
Soft tissues (gums, pulp etc)
Hazards of radiation…
Damages tissue
Can damage/alter DNA/chromosomes causing mutations and death of the cell
What can a high X-ray dose cause?
Skin can appear reddened and inflamed similar to sunburn
Distraction of the immune system calls
Leukaemia
Radiation sickness
Death
What does ALARP stand for?
As low as reasonably possible
What does ALARA stand for?
As low as reasonably achievable
Principals of ALARA/P
What percentage can this reduce scatter by?
Use of fast film - f speed
Short exposure time
Rectangular collimator tube
Can help reduce scatter by 40%
Who does IRR protect and how do you comply to IRR
Protects staff and classified workers
Appoint a legal person
Appoint RPA
Appoint RPS
Who does IR(ME)R protect?
Protects safety of patients
Role of RPA
They are outside the practice
Must do certified checks every 3 years
Make a contingency plan
Carry out risk assessments that are reviewed every 3 years
What is the controlled area and safety zone?
Controlled area - 1.5m
Safety zone- 2m
Role of RPS
Inside the practice
Train staff
Drawing up and updating the local rules
Who is the referrer?
The dentist who refers the patient for radiation exposure
Who is the IRMER practitioner?
A dentist or specialist dental radiographer who takes the responsibility for justifying the taking of the X-ray
Who is the operator?
Any staff member who carries out part or all of the practical duty’s involved with the exposure and processing of the X-ray
This can include a trainee dental nurse.
What must the local rules contain?
Contingency plan
Dose levels
Safety of pregnant staff
Name of RPA/RPS
Advantages of digital X-rays?
Radiation levels reduced
No chemicals required
Viewing make quicker
Disadvantages of digital X-rays
Images can be manipulated/altered
Legal problems can arise from editing an X-ray
Expensive equipment
What makes up a dental film packet?
Black paper
Film
Black paper
Foil
Plastic wrapping
What is a PA X-rays and what does it help to detect?
Periapical - shows whole tooth
Dental caries
Abscess
Root fracture
Bone levels
What does a horizontal bitewing detect?
interproximal caries
restoration overhangs
caries under existing restorations
occlusal caries
What does vertical bitewings detect?
Bone levels
Periodontal pockets
What does anterior occlusal X-rays detect?
Impacted canines
Supernumerary
Palatal Cysts
Large intraoral film
What does DPT stand for?
Dental panoramic tomograph
What does OPG stand for?
Orthopantomograph
What view does a lateral oblique X-ray show and what it detect?
Side image of upper and lower jaw on ONE SIDE ONLY
detecting unerupted or impacted third molars
What does a cephalostat show and what is it used for?
Shows side image of whole skull
Used to monitor jaw growth and complicated orthodontics
What is an intensifying screen?
A sheet inside the extra oral cassettes that glows when exposed to radiation
They give off a blue light so their is less radiation and a shorter exposure time.
List the chemicals used in manual film processing
Developer - alkaline, produces latent image, solution oxides in the air
Fixer - acidic, fixes the image onto the film
Water - used for rinsing off chemicals
What temperature range should the chemicals be in?
18-22
What is a step wedge used for?
To do daily tests on the chemicals
What is a grade 1 X-ray?
No errors at all
Minimum of 70% of all exposures
What is a grade 2 X-ray?
Diagnostically expectable
Some errors
Maximum of 20% of all exposures
What is a grade 3 X-ray?
Unacceptable quality
Unable to use
Maximum of 10% of all exposures
How are X-rays disposed?
As non infectious hazardous waste
Why would you get a blank film?
X-ray not switched on
Why would you get a fogged (black) film?
Exposed to light before exposure
What is coning?
Where the film isn’t lined up to the collumator
What causes elongation?
Collumator angle is too shallow and produces a long image
What causes foreshortening?
Collumator angle too steep and produces squat image
Squashed, stunted
What does a DPT/OPG help to detect?
Jaw fractures
Presence or position of teeth
Ortho or wisdom tooth assessment
Fracture of the neck of the condyle
