| Purpose:TACE (Transcatheter arterial chemoembolization) operation is widely used in current interventional radiation therapies, which may create high radiation exposure to the eye lens of the operator, leading the cloudy to the eye lens or cataract.In this study, we compared the eye lens doses and investigated the differences due to a doctor’s postures, FOV(Field of view), beam quality, and projections with different protection eye wears during TACE using the Monte Carlo method and a 3D voxel phantom called RPI-AM. Methods:We simulated and calculated the annual equivalent doses of the left and right eye lenses of the doctor wearing lead glasses, lead mask, or nothing, in four different tasks of research:1. Standing postures:facing 45-degree to the left,45-degree to the right and facing the patient.2. FOV(Field of View):10cm, 20cm,30cm,40cm.3. Beam quality:tube voltage 90kVp, Cu filter 0.1 mm; tube voltage 90kVp, Cu filter 0.2mm; tube voltage 80kVp, Cu filter 0. lmm; tube voltage 80kVp, Cu filter 0.2mm; 4. Projection:PA, LAO45°, RAO45°. Results:Influences of standing postures:With no protection, the equivalent doses of the eye lens in three standing postures are all exceeded the dose limit 20 mSv, decreasing in the order of 45-degree on the left, facing the patient and 45-degree on the right. With lead glasses, the equivalent doses in different directions are close to the dose limit of IBSS, and with lead mask, the equivalent doses are all below 20 mSv. The absorbed doses in two eye lens are different:the doses of left eye lens are less than the right lens for 45-degree on the left, while the dose results of the left lens are greater than the ones of the right lens in the other two directions. Influences of FOV:The field of view of the DSA beam have a sensitive influence on the dose of the eye lens. With different protections, Annual equivalent dose increased by the rise of FOV as linear under 30cm. And FOV have more influence on the left eye lens than right. While no protections on the eye lens, the Annual equivalent dose quickly reached the limit by ICRP, comparing the wearing lead glasses, the limit only arrived at FOV 30cm. Wearing lead mask, the equivalent dose always stay under the limit of 20mSv every year. Influences of beam quality:the two parameters have different behaviors on the annual equivalent dose, which is that the influence of the tube voltage is sensitive while the Cu filter is insensitive. Could only see the differences when wearing the lead glasses and lead mask, also not too much. They all have the similar influences on the left and right eye lens. For the limit of theICRP, while no protections, all the situations are above the limit, same as the high tube voltage situation wearing the lead glasses. Other combination are all safe with no reach to the limit. Influences of projections:Projection as PA, the annual equivalent dose of the doctor’s eye lens are most than the other two projections. RAO45° is less than PA, while LAO45° only have the half value of the PA projection. This result is similar comparing the different protections and also have the same influence on the left and right eye lens except for the LAO45° wearing lead glasses situation. All the annual equivalent dose are above the limit except for the LAO45° with lead mask. Conclusion: In order to reduce the eye lens dose, we suggested doctor wear lead mask, avoid turning left, use small FOV and tube voltage of the DSA system, suitable Cu filter and LAO45° projection will also make the eye lens safety when operating in TACE without eye lens protections, and pay more attention to the left lens protection if lead mask is not available. |
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