数字乳腺X射线摄影中不同靶/滤过组合对辐射剂量的影响

Effect of Target/Filter Combination on Radiation Dose in Digital Mammography

目的探讨数字乳腺X射线机应用Mo/Mo、Mo/Rh、W/Rh 3种不同靶滤过组合对辐射剂量的影响,以便优化选择摄影技术参数,降低受检者的辐射损伤。方法应用Siemens MAMMOMAT Inspiration数字乳腺X射线机,Ray Safe X射线质量检测仪。首先使用全自动曝光模式对不同厚度的PMMA模体进行曝光并记录管电流量、管电压等摄影参数,然后采用相同的管电压、管电流量、压迫厚度在不同的靶滤过组合(Mo/Mo、Mo/Rh、W/Rh)模式下进行手动曝光,读取并记录体表入射剂量(ESD),计算平均腺体剂量(AGD)。对不同模体厚度在使用3种不同靶滤过组合时产生的平均腺体剂量进行随机区组的方差分析,采用线性相关和回归观察不同靶滤过组合及不同厚度与AGD的相关性并列出直线回归方程。结果 3种靶滤过组合对不同厚度模体产生的AGD差异有统计学意义,Mo/Mo组合的AGD最高,W/Rh组合的AGD显著降低。使用不同靶滤过组合时模体厚度与AGD均呈显著正相关。结论 W/Rh组合AGD明显低于其他两种组合,乳腺X射线摄影时采用W/Rh组合是最佳选择,可显著降低受检者的辐射剂量。

Objective To discuss the effect of different target/filter combinations （ Mo/Mo, Mo/Rh, W/Rh ） on radiation dose in digital mammography. Chose optimal exposure parameters was so important to ensure image quality and reduce radiation injury. Methods First peform strict quality control on mammography before experiment. The same exposure conditions, pressure, compression thickness, and different target/filter combinations were employed under the AOP and Manual exposure modes. Record the target/filter combination for each exposure and read the entrance surface dose（ESD） on Ray Safe. Calculate average glandular dose（AGD） and the means. One -way analysis of variance and SPSS 17.0 were used in statistical analysis. Methods AGD values which were acquired in the phantom with different thickness and three different target/filter combinations were statistically different. The AGD values of were always the lowest for W/Rh but highest for Mo/Mo. With the increase of phantom thicknesses, the AGD values which were acquired with Mo/Mo, Mo/Rh, and W/Rh target/filter combinations were increased. Conclusion W/Rh combination for 10 -70 mm phantom thicknesses which respectively can reduce the radiation dose, were the optimal choose of three different target/filter combinations, also they can provide the best image quality with lowest radiation dose.