不同阳极滤过器组合的乳腺DR成像性能对比

Experiments on Choice of the Anode/Filter Combination for Digital Mammography

目的对数字乳腺X射线摄影不同阳极和滤过器组合成像性能进行对比。方法采用不同厚度乳腺成像体模、选择不同的阳极/滤过器组合,在自动曝光模式下成像。测量图像信噪比和腺体吸收剂量,并引入图像品质因数综合评价成像性能的好坏。结果对于不同厚度的乳腺体模,使用钨铑组合平均腺体剂量比其他组合可以降低25%~42%,图像品质因数高于其他组合5%~37%。随着腺体厚度的增加平均腺体吸收剂量逐步增加,而图像信噪比则与平均腺体吸收剂量成反比。结论当体模厚度在4~9cm时,钨铑组合成像性能最佳,因此在临床使用中应充分考虑临床实际需要来选择适宜成像技术,在保证临床图像质量的同时尽量降低受检者的辐射风险。

Objective To study on the choice of the anode/filter combination for digital mammography system.Methods mammography accreditation phantom with phantom thickness from 4 cm to 9 cm was used to simulate human breast tissue and three different combinations of anode/filter material were employed under the automatic exposure mode.The image signal to noise ratio（SNR） and mean glandular dose（MGD） were measured.The figure of merit（FOM） was used to evaluate the imaging performance of digital mammography.Results For 6~9cm phantom thicknesses,the MGD of tungsten anode and rhodium filter combination（W/Rh） can be lower by 25%~42% than other two combinations;the FOM of W/Rh achieved higher by 5%~37% than others.The SNR was decreased with the increase of phantom thickness,and the MGD was getting higher with thicker phantom.Conclusion Based on these measurements,the use of the W/Rh anode/filter has the best imaging performance,so the optimization for digital mammography is very important for clinical use in order to keep the good image quality and reduce the radiation dose.