Objective To study the methods for estimating cumulative exposure dose in human lens of the medical radiation workers in hepatic arterial chemoembolization.
Methods Alderson Radiation Therapy (ART) phantom was used to simulate the scenario commonly used in hepatic arterial chemoembolization according to the position and projection conditions.Human lens dosimetryHp (3)was used to estimate the cumulative exposure dose of the human lens in the ART phantom (internal measurement method),and at the same time thermoluminescence (TLD) elements on eyelids were used to estimate the dose (external measurement method).Then the difference of two kinds of measurement results was calculated.
Results When lead glasses were off,for internal measurement method,the cumulative exposure dose to right lens(18.9±0.8)μSvwas lower than that to left lens(54.1±2.3)μSv(t=-63.31,P<0.05).For external measurement method,the cumulative exposure to right lens(62.3±1.4)μSvwas also lower than that to left lens(67.1±1.2)μSv(t=-11.71,P<0.05).The cumulative radiation exposure doses to left eye lens were attenuated by 30%-70% when lead glasses were on;however,the protection effect of lead glasses to right lens was not as good as that to left lens (t=0.11,t=0.03,P>0.05).
Conclusion The results of the two measurement methods are similar for left human lens,but for right lens the cumulative dose equivalent detected by external measurement method is significantly higher than that by internal measurement method.Therefore,Hp (3) may overestimate the cumulative exposure dose to right human lens with a maximum error of 65%.
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