radiation protection Flashcards
What are the International Commission on Radiation Protection’s 3 principles of dose limitation?
- Justification
- Optimisation
- Limitation
How often should a child with high caries risk have BW taken?
Every 6 months.
How often should a child with moderate caries risk have BW taken?
Every year.
How often should a child with low caries risk have BW taken?
Every 12-18 months in primary dentition.
Every 2 years with permanent dentition.
For an adult with high caries risk, how often should BW be taken?
Every 6 months.
For an adult with moderate caries risk, how often should BW be taken?
Every year.
For an adult with low caries risk, how often should BW be taken?
Every 2 years.
Why is a high voltage (70kV) used to optimise the X-ray beam?
Because high energy x-rays penetrate through the patient (less exposure to more harmful wavelengths).
What type of collimation should be used to optimise?
Rectangular
What element is used to filter the x-ray beam?
Aluminium
What type of potential is needed to produce a constant current?
Constant potential.
How does rectangular collimation optimise the x-ray beam?
It reduces the dose by 45% and fits the shape of the film.
How many cm is the legal requirement of focus to skin distance?
20cm
Which form of protection is not justified in dental radiography?
Lead aprons.
During which dental view would a lead apron be recommended in a pregnant patient?
Vertex occlusal (but this is rarely performed and can be replaced by other views).
Which dental x-ray view may warrant the use of a thyroid collar?
Upper standard occlusal
(usually used during ortho assessment).
What is the annual dose limit for a classified worker?
20 mSv
What is the annual dose limit for a non-classified worker?
6 mSv
What is the annual dose limit for the general public?
1 mSv
Which category of workers do dental professionals come under?
Non-classified workers.
How far must the controlled area extend from the pt and x-ray tube?
1.5m
How far away is recommended for the operator to stand from the pt and x-ray tube?
2m or more
Are film badges mandatory for non-classified workers?
No but IRMER recommend considering this for those whose weekly workload exceeds 100 IO or 50 panoramic films.
Radiation dose for a classified worker:
20 mSv
Radiation dose for a non-classified worker:
6 mSv
Radiation dose for public / carers
1 mSv
Radiation dose in a routine bitewing.
0.005 mSv
OPT radiation dose
20 mSv
