Biological effects of radiation

Question 1

what is the meaning of dosimetry

Answer 1

dosimetry is the measure of radiation dose

Question 2

what is a reference dose

Answer 2

these are the dose levels set for different types of xray examinations

Question 3

what is radiation absorbed dose

Answer 3

this is the amount of radiation absorbed from the xray beam

Question 4

what is the units for radiation absorbed dose

Answer 4

the gray (GY)
1 Gray = 1 J/kg-1

it is common to usee the subunits of the gray as it is a large unit so we would use milligrays and micrograys

Question 5

what is equivalent dose (Ht)

Answer 5

this is a measure oif the harmful effects of different types of radiation and we are able to measure this by using radiation weighting factors

for example alpha particles cannot penetrate far into tissue and they have a weighting factor of 20

Question 6

what is the equation to calculate the equivalent dose

Answer 6

equivalent dose (Ht) = radiation absorbed dose x weighting factor of specific type of radiation

measure in sieverts
since the weighting factor for xrays is 1 the equivalent dose would equal the radiation absorbed dose

Question 7

what is effective dose

Answer 7

this allows the comparison of doses to different body parts

we do this because different tissues have different sensitivities to radiationn so it is important to reflect the risk to different tissues

we do this by using the tissue weighting factors

Question 8

how do we calculate the effective dose

Answer 8

effective dose = equivalent dose x tissue weighting factor

Question 9

what is collective effective dose

Answer 9

this is the measure of the total effective dose to a population kmeasured in man-sieverts(man-Sv)