Shielding effect of lead glasses on eye lens exposure in interventional radiologists / 中华放射医学与防护杂志

Objective To study the shielding effect of equivalent thickness and size of lead glasses on eye lens of interventional radiologists.Methods Based on the human voxel phantom and MCNPX software,doses to eye lens of radiologists were simulated under different conditions of wearing lead glasses and beam projections,and measurements were performed with anthropomorphic phantom placed with eye lens dosimeters to verify simulation results.Results The results showed that the dose to eye lens reduced by a factor from 3 to 9 when the equivalent thickness of glasses ranged from 0.1 to 1.0 mm Pb with a len size of 20 cm2.The dose reduction factors (DRF) not only depended on the lead equivalent,but also on the beam projection of X-rays.However,the increase in DRF was not significant whenever the lead equivalent of glasses was larger than 0.35 mm.Furthermore,the DRF was proportional to the size of glass lens from 6 to 30 cm2 with the same lead equivalent.The simulation results were in well agreement with the measured ones.Conclusions For more reasonable and effective protection of the eye lens of interventional radiologists,a pair of glasses with a lead equivalent of 0.5 mm and large-sized lens is recommended.

Organ dose evaluation for CT scans based on in-phantom measurements / 中华放射医学与防护杂志

Objective To explore the organ doses and their distributions in different projections of CT scans.Methods The CT values were measured and the linear absorption coefficients were derived for the main organs of the anthropomorphic phantom to compare with the normal values of human beings.The radiophotoluminescent glass dosimeters were set into various tissues or organs of the phantom for mimic measurements of the organ doses undergoing the head,chest,abdomen and pelvis CT scans,respectively.Results The tissue equivalence of the phantom used in this study was good.The brain had the largest organ dose undergoing the head CT scan.The organ doses in thyroid,breast,lung and oesophagus were relatively large in performing the chest CT scan,while the liver,stomach,colon and lung had relatively hrge organ doses in abdomen CT practice.The doses in bone surface and colon exceeded by 50 mGy in a single pelvis CT scan.Conclusions The organ doses and their distributions largely vary with different projections of CT scans.The organ doses of colon,bone marrow,gonads and bladder are fairly large in performing pelvis CT scan,which should be paid attention in the practice.