Radiation Safety Flashcards
what is the absorbed dose?
amount of ENERGY DEPOSITED in a medium per unit MASS of the medium
what is the absorbed dose measured in?
JOULES/Kg
what is the unit used for absorbed dose?
Grays (Gy)
The equivalent dose is…
a measure allowing different radio-biological effectiveness of different types of radiation into account.
the equivalent dose = (formula)
the absorbed dose x radiation weighting factor
what is the radiation weighting factor for X-rays, gamma rays and beta particles?
Wr = 1
what is the Wr for alpha particles?
20
Give an example of how the equivalent dose works?
- different types of radiation will penetrate tissues in very different ways…
- e.g, alpha particle will be totally absorbed but X-rays will have further penetration (the will both also have different absorbed doses)
the unit for equivalent dose is..
sievert (Sv)
if the radiation weighting factor is 1 then the absorbed dose is equal to the…
equivalent dose
The effective dose…
allows doses from different investigations of different parts of the body to be compared
the effective dose converts dose to an…
equivalent whole body dose
The tissue weighting factor is…
an indication of how sensitive an area is to radiation
name the 5 most sensitive areas
- thyroid
- gonads
- skin
- breasts
- red bone marrow
The effective dose = (equation)
equivalent dose x tissue weighting factor
the effective dose is measured in…
Sv (sieverts)
name 4 types of background radiation
- radon gas
- gamma rays
- cosmic rays
- food and drink
what is the average exposure to background radiation per year in the UK?
2.5mSv (m= x10-3)
Where does radon gas come from and how is it harmful?
- a breakdown product of uranium in the ground (natural) and is harmful if inhaled (can cause lung cancer)
the range of yearly exposure to radiation from radon gas is..
300-100,000 micro Sv
levels of radon gas are highest indoors or outdoor?
indoors as levels allowed to build up
gamma rays come from?
radioactivity in the earth and building materials (natural)
- the dose depends upon the material
levels of gamma rays are highest indoor or outdoors?
the same in both
the average yearly range of background radiation from gamma rays is..
100-1000 micro Sv
