7: Radiation Protection Principles Flashcards
What is the most important principle in the radiation industry?
ALARA - as low as reasonably possible
ALARA considers 3 elements as per ICRP…
- Justification - the positives outweigh the negatives
- Limitation
- Optimization
NSRDR contradicts RPR by saying a non-NEW should limit their yearly exposure to…
0.5 mSv/year
3 basic ways of controlling exposure
- time
- distance
- shielding
How do you calculate exposure dose?
exposure dose = dose rate X time
When you double your distance from a source, the intensity reduces by a factor of what?
Factor of 4
What is the Inverse Square Law used for?
To calculate the radiation at a certain distance
What factors do you need to know to calculate the Inverse Square Law?
The dose rate at a given distance
What is a collimator used for?
To partially surround source to absorb radiation not directed towards radiographed object
What is a collimator made of?
Usually tungsten, sometimes lead
What is a value layer used for?
To express the effectiveness of a shielding material
The amount of exposure is directly proportional to what?
Duration of exposure
Distance is an effective means of protection against gamma rays because…
Radiation intensity decreases in proportion to square of the distance.
Lead is frequently employed in shielding against radiation from gamma ray sources because of its…
High absorption for a given thickness and weight
A trainee is allowed to operate an exposure device…
Under direct supervision and continuous observation of a certified exposure device operator.
