| 张原生,王晓成,郭子泉,王建明.数字乳腺X射线摄影中管电流量优化的实验研究[J].中华放射医学与防护杂志,2022,42(2):144-149 |
| 数字乳腺X射线摄影中管电流量优化的实验研究 |
| Experimental study on optimization of mAs in digital mammography |
| 投稿时间：2021-08-16 |
| DOI：10.3760/cma.j.cn112271-20210816-00327 |
| 中文关键词: 低剂量 辐射剂量 数字乳腺X射线摄影 |
| 英文关键词:Low dose Radiation dose Digital mammography |
| 基金项目: |
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| 中文摘要: |
| 目的 探讨数字乳腺X射线摄影中不同靶/滤过组合时降低管电流量（mAs）对图像质量与辐射剂量的影响。方法 不同靶/滤过组合时，以自动曝光模式（AEC）的mAs为基础，分别降低10%、20%、30%、40%、50%时对厚度为4.4 cm的模体进行曝光，测量所得图像的对比噪声比（CNR）、信噪比（SNR）、品质因子（FOM）与平均腺体剂量（AGD）。在满足图像质量要求的前提下，通过计算FOM，找出两种靶/滤过下最优mAs及相应的AGD。对模体中3种结构影像特征进行主观评价，同时比较计算AGD与显示AGD间关系。另外，对满足图像质量要求的mAs与密度曝光档位相对应，计算并比较两者mAs均值。结果 两种靶/滤过中显示AGD均小于计算AGD，Mo/Mo被低估22.5%~23.7%，计算AGD值与显示AGD值差异有统计学意义（F=4 982.86、5 555.48，P<0.05）。W/Rh被低估13.1%~14.2%，计算AGD值与显示AGD值差异有统计学意义（F=18 859.09、15 973.55，P<0.05）。Mo/Mo组合中，mAs降低20%时，FOM可增加9.6%为最大值，且计算AGD减少18.8%。W/Rh组合中，mAs降低10%，FOM可增加5.1%为最大值，且计算AGD减少11.9%。在满足图像质量的前提下，两种靶/滤过组合评价模拟纤维时，mAs降低30%；评价模拟钙化时，mAs降低20%；评价模拟肿块时，Mo/Mo组合mAs降低40%，W/Rh组合mAs降低30%；影像质量评分均与AEC无明显差异（P>0.05）。密度曝光档位（-1~-3）可与降低的mAs （10%~30%）对应。结论 不同靶/滤过组合时，调节管电流量可以在不影响图像质量的同时降低辐射剂量。 |
| 英文摘要: |
| Objective To evaluate the effect of reducing mAs on image quality when different target/filter combinations are used in digital mammography. Methods In different target/filter combinations, based on the mAs of automatic exposure control(AEC), the reduction of mAs by 10%, 20%, 30%, 40% and 50% respectively were used to expose the phantom with 4.4 cm thickness. The contrast to noise ratio(CNR),signal to noise ratio(SNR), figure of merit(FOM) and average glandular dose(AGD) of the resulting image were calculated. While the image quality was ensured, the optimal mAs and the corresponding AGD under the two target/filter combination were conducted by calculating the FOM. The image features of three tissues of phantom were subjectively evaluated, and the relationship between the calculated AGD and displayed AGD was compared. The mAs that meets the image quality requirements is corresponded with the density exposure gear, and the average values of the mAs for two method were calculated and compared. Results In two targets/filters combinations, the displayed AGD was less than the calculated AGD, and Mo/Mo was underestimated by 22.5% to 23.7%. The calculated and displayed AGD values were statistically different (F=4 982.86, 5 555.48, P<0.05). W/Rh was underestimated by 13.1% to 14.2%. The calculated and displayed AGD values were statistically different (F=18 859.09,15 973.55, P<0.05). In the Mo/Mo combination, when the mAs was reduced by 20%, the FOM could be increased by 9.6% for the maximum value, and the calculated AGD was decreased by 18.8%. In the W/Rh combination, when the mAs was reduced by 10%, the FOM was increased by 5.1% for the maximum value, and the calculated AGD was decreased by 11.9%. While the image quality was ensured, the mAs was reduced by 30% for evaluating simulated fibers, and by 20% for evaluating simulated specks in the two targets/filter combinations. For evaluating simulated masses, Mo/Mo combination reduced the mAs by 40%, and the W/Rh combination reduced the mAs by 30%. And the image quality scores in above were not significantly different from those in AEC method (P>0.05). The density exposure gear(-1 to -3) could correspond with the reduced mAs(10%-30%). Conclusions Under different target/filter combination, the tube mAs could be reduced when the image quality was ensured. |
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