乳腺X线摄影射线剂量对乳腺X线片质量的影响

目的通过调节乳腺X线摄影的曝光剂量,评价乳腺X线摄影中平均腺体剂量(average glandular dose,AGD)对图像质量的影响。资料与方法应用数字化全景乳腺机系统和PASMAM模体,手动控制条件(kV、mAs),对不同厚度的PASMAM模体在不同AGD条件下进行摄影。采用非参数统计分析不同AGD相同厚度以及相同AGD组不同厚度模体钙化和肿块的显示程度差异是否存在统计学意义,并分析图像信号噪声比(SNR)随剂量和厚度的变化。结果相同曝光剂量条件下,SNR随模体厚度的增加而下降,相同模体厚度SNR随曝光剂量的增加而增加。实验范围内的相同厚度模体组合,在不同AGD条件下,显示钙化和肿块的能力差异无统计学意义(P>0.05)。结论数字化全景乳腺X线摄影盲目提高AGD值会增加患者受辐射量,并不能提高显示钙化和肿块的能力。

Influence of Average Glandular Dose for Breast Cancer Screening and Diagnosis in Mammography

Objective To evaluate the influence of average glandular dose(AGD) on image quality for full field digital mammography(FFDM).Materials and Methods PASMAM phantom with different thickness was exposed under different dose(AGD) by using FFDM and manual controlling exposure conditions(kv,mAs).Non-parameter test were used to evaluate the image quality under different AGD,including the ability of mass and calcification detection and signal-noise ratio(SNR).Results SNR decreased as the thickness of model increased under the same AGD,and in same model thickness,the SNR increased with AGD increased.No statistical different was found for the ability of calcification and mass detection.At the different AGD level and same thickness model combination,t1.5mGy was the best exposure AGD for breast cancer diagnosis in mammography.Conclusion Increasing AGD could not improve the image quality of full field digital mammography.