| Resumo: | Background . CT scan is a contributor to the largest X-ray radiation in radiology
departement. It will increase with the increasing use of Head MSCT 64 slice
examination. The radiation will radiate the head (primary radiation) and
surrounding organs (secondary radiation) . One around the affected organ is the
thyroid . Radiation on the thyroid should not exceed the prescribed standards .
Radiation dose can be reduced by use of 0,5 mm thyroid shields. This study aims
to determine the scattered radiation dose received by the thyroid at 64 slice Head
MSCT 64 slice examination and decrease the radiation dose to the using 0,5 mm
thyroid shields.
Materials and Methods . The study was conducted on patients who underwent
Head MSCT 64 slice without and with contrast proper to the request of the
clinician. Examination using a MSCT 64 slice, Phillips brand. Radiation
measurements performed twice with the TLD . The first measurement is to
determine the dose of radiation without the use of shields . TLD placed on the
surface of the thyroid , without shielding when patients underwent MSCT Head
64 slice without contrast . The second examination to determine the radiation dose
with thyroid shields, TLD placed on the surface of the thyroid and below to the
thyroid shields, while patients undergoing MSCT Head 64 slice with contrast.
Results and Discussion . there was a diferrence in thyroid scattering radiation
dose at Head MSCT 64 sclice examination between using of thyroid shealding
and without shielding tiroid 0,5 mm. The average of scattered radiation dose
which received by thyroid at the Head MSCT 64 slice examination was1.25mSv.
It was larger then standard dose that determined by Cohnen et al. (1,1 mSv).
0.5mm thyroid shields can reduce the radiation dose up to70.9% (1.25 mSv to
0.34mSv). This value is greater than 58% (the standard decresed). The amount of
neck circumference affects the radiation dose received by the thyroid, the greater
the smaller neck thyroid dose received.
Conclusion. 0.5mm thyroid shields can reduce the scattering of radiation dose to
less than standard.
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