Lec #3 - Minimizing Exposure to Personnel Flashcards
(13 cards)
At what level of dose should someone be declared a radiation worker?
likely to receive a radiation dose in excess of 1/20th of the whole body dose limit to radiation workers.
Radiation workers – 20 mSv/year
1/20th of 20 mSv = 1 mSv
What is the most effective means for protection vs ionizing radiation?
- Distance
- should try for a minimum distance of 3m
When at a 90 degree angle and 1m away from the primary x-ray beam what is the intensity of the scatter radiation?
- 1/1000
What methods & techniques can be applied to reduce dose
- avoid repeats
- use filtration (removes low energy photons)
- collimate
How many times should x-rays scatter before entrance to control booth?
- 2 times
What is a controlled vs uncontrolled area?
Controlled Area: occupied ONLY by Occupationally Exposed
Uncontrolled Areas: Public/Others
What is a primary vs secondary barrier?
Primary – for main beam (any wall primary beam is directed toward or floor)
Secondary – barrier for scatter (secondary or leakage radiation)
Why shouldn’t you fold led aprons?
don’t fold the aprons – will soften the lead and can crack
What amount of protective lead is needed for the following kVs?
- 100kV or less
- 125kV or less
- 150kV or less
- 0.25mm lead
- 0.35mm lead
- 0.5mm lead
What thickness of lead do protective gloves need?
0.25mm
What thickness of lead does gonadal shielding need?
0.25mm lead
- or at 150kVp need 0.5mm
What thickness of lead is recommended for thyroid collars?
0.50mm
What is a benefit of standing on the image intensifier side during an exposure
Scatter near entrance of patient is more than scatter going towards the image intensifier.
Better to stand on image intensifier side.
