数字化胸部X射线摄影中铜滤过对受检者辐射剂量的影响

采用西门子公司生产的数字化X射线透视摄影系统,在不同的附加铜滤过(0、0.1、0.2、0.3 mm)下,对不同厚度的聚甲基丙烯酸甲酯(PMMA)模体进行胸部摄影。利用对比度噪声比评估不同附加铜滤过对图像质量的影响,同时使用辐射剂量仪记录不同铜滤过下的体表入射剂量,以探讨数字化胸部X射线摄影中,附加铜滤过对受检者体表入射剂量的影响。结果表明,不同附加铜滤过下,图像的对比度噪声比没有明显变化。在不同厚度的PMMA模体下,附加0.1 mm铜、0.2 mm铜、0.3 mm铜后的体表入射剂量,与没有添加铜滤过时相比分别下降了24%~29%、33%~42%和39%~47%,且差别均有统计学意义(p<0.05)。说明在数字化胸部X射线摄影中,适当增加铜滤过,不会影响图像质量,但能有效减少受检者的体表入射剂量。

The impact of additional Cu filtration on radiation dose in digital chest radiography

By using the digital X ray fluoroscopy camera system produced by Siemens, under different additional copper filters (0, 0.1, 0.2, 0.3 mm), chest photography is performed on PMMA phantoms of different thicknesses. Using the contrast-to-noise ratio to evaluate the impact of different additional copper filters on image quality, and using a radiation dosimeter to record the entrance surface dose under different copper filters, in order to explore the effects of additional copper filters on the body surface dose in digital chest X ray photography. The results show that under different additional copper filters, the contrast-to-noise ratio of the image does not change significantly. Under the PMMA phantoms with different thicknesses, the entrance surface dose decreased by 24%-29%, 33%-42% and 39%-47%, after adding 0.1 mm copper, 0.2 mm copper, and 0.3 mm copper respectively, compared with the absence of copper filtration, and the difference was statistically significant (p<0.05). It shows that for the digital chest X ray photography, the appropriate increase of copper filtering will not affect the image quality, but it can effectively reduce the body surface dose.