Monte Carlo modelling of 90Sr/90Y and 85Kr beta fields for Hp(3) measurements.
In support of research aimed at developing a thermoluminescence dosemeter capable of accurately measuring ionising radiation doses to the lens of the eye, Monte Carlo modelling of a standard beta exposure set-up has been performed. It was found that electrons with an energy distribution corresponding to the beta emission spectrum from (85)Kr deposit negligible doses at a depth of 3 mm in tissue, but doses from (90)Sr/(90)Y are significant; free in air and fluence-to-Hp(3,θ°) and -Hp(0.07,θ°) conversion coefficient data were found for this field for exposures at 0°, 30° and 60° angles of incidence, and the response characteristics of the new eye dosemeter were evaluated. It was shown that the results were not affected greatly by the shape of the calibration phantom. However, it was demonstrated that the presence of intermediating air and beam flattening filters hardens the energy distribution of the field at the point of test, relative to a raw (90)Sr/(90)Y source, and this impacts dose depositions.
Public Health England, Centre for Radiation Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK.
J S
JS
Eakins
S T
ST
Baker
N J
NJ
Gibbens
P J
PJ
Gilvin
L G
LG
Hager
R J
RJ
Tanner
D003198:Computer Simulation; D004583:Electrons; D005123:Eye / Q000528:radiation effects*; D006801:Humans; D007727:Krypton Radioisotopes / Q000032:analysis*; D015233:Models, Statistical; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D017785:Photons; D011829:Radiation Dosage; D011835:Radiation Protection; D012062:Relative Biological Effectiveness; D013326:Strontium Radioisotopes / Q000032:analysis*; D015021:Yttrium Radioisotopes / Q000032:analysis*
D007727:Krypton Radioisotopes; D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes