Hall 16 - Radiation Protection Flashcards
What are the units for absorbed dose?
1 gray (Gy) = 1 J/kg = 100 rad
What are radiation weighting factors (WR)?
Dimensionless multiplier used to interconvert/compare between different types of radiation
Reflect RBEs applicable to low doses and LDRs for late stochastic effects
What is the weighting factor of a photon?
1
Electrons = 1
Protons = 2
alpha particles and heavier = 20
Neutrons = continuous function of energy up to 20
How do you calculate equivalent dose?
Absorbed dose x weighting factor
Unit = Sv
*1 Gy neutrons is not the same biologic effect as 1 Gy photons, but 1 Sv of either reflects equal biologic effect
How many rem in a Sv?
1 Sv = 100 rem
What is tissue weighting factor (WT)?
Dimensionless multiplier that reflects different radiosensitivity of different tissues with regard to a biological endpoint
How do you calculate effective dose?
Absorbed dose x weighting factor (WR) x tissue weighting factor (WT) summed across all exposed tissues
Unit = Sv
What is the committed equivalent or effective dose?
The integral dose over 50 years from an internally incorporated radionuclide
What is the collective equivalent or effective dose?
The sum dose over an entire population (units of person-Sv)
What dose limit principle governs all radiation exposures?
ALARA
What is the NRCP defined dose limit for radiation workers?
50 mSv/year (0 before age 18)
Cumulative lifetime: 10 mSv x age
(whichever is less)
What is the NRCP defined dose limit for radiation workers’ lens?
50 mSv/year
What is the NRCP defined dose limit for radiation workers’ skin, hands, feet?
500 mSv/year
What is the NRCP defined dose limit for a fetus?
0.5 mSv/month AFTER declared pregnancy
What is the NRCP defined dose limit for general public?
1 mSv/year (continuous/frequent)
5 mSv/year (infrequent)
