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目的应用ALVIM统计学体模TRM,探讨乳腺计算机X线摄影(CR)获得尺寸最小的Al2O3斑点(钙化灶)和尼龙纤维(肿块灶)信号的能力。方法将具有各5种大小不同Al2O3斑点和尼龙纤维组成的ALVIM统计学体模TRM置于成像板(IP)上,用钼靶X线机26kV,调节毫安量,选择适当图像处理参数,获得一张密度值D=0·70±0·05的实验照片,用5值判断法取得每一行由5个信号和噪声所组成的10行信号的记分总值,用ALVIM统计学体模的计算公式计算出一组真阳性概率P(S/s)和假阳性概率P(S/n)值,绘制ROC曲线,并计算出每种信号的判断概率值Pdet,再用SPSS10·0统计学单因素方差分析软件处理数据,获得尺寸最小的钙化灶和软组织肿块灶。结果用概率统计方法获得制作ROC曲线的数据和判断概率平均值Pdet,5种大小不同的Al2O3斑点(钙化灶)中,0·20mm的Pdet=0·6250最小,0·55mm的Pdet=0·9000最大,而0·20mm与0·25mm的Pdet差异无统计学意义,与其他的差异有统计学意义;5种大小不同的尼龙纤维(肿块灶)中,0·45mm的Pdet=0·5313最小,1·00mm的Pdet=0·8813最大,而0·45mm的与0·60mm的差异无统计学意义,0·45mm与其他的差异有统计学意义。结论应用ALVIM统计学体模TRM制作ROC曲线和获得判断概率值Pdet的计算简单、快捷,宜于日常临床工作开展的评价影像质量控制,值得推广。
Objective To evaluate the ability of breast tissue computed tomography (TRM) to obtain the smallest size of Al 2 O 3 spots (calcifications) and nylon fibers (lumps) using ALVIM statistical phantom TRM. Methods ALVIM statistical phantom TRM with five different sizes of Al 2 O 3 spots and nylon fibers was placed on an imaging plate (IP) with a mammography X-ray machine at 26 kV to adjust the milliamps and select the appropriate image processing parameters to obtain A density of D = 0.70 ± 0.05 experimental photos, 5-value judgment obtained by each line of 5 signals and noise composed of 10 lines of the total score of the signal, calculated using ALVIM statistical phantom Formula to calculate a group of true positive probability P (S / s) and false positive probability P (S / n) value, draw the ROC curve and calculate the probability of each signal judgment probability Pdet, then SPSS10 · 0 statistical single Factor analysis of variance software to process the data to obtain the smallest calcifications and soft tissue mass lesions. Results The ROC curve data and the average probability of determination Pdet were obtained by probability and statistics. Among the five kinds of Al2O3 spots (calcifications) with different sizes, the Pdet of 0 · 20mm was the smallest, the Pdet of 0 · 55mm was 0 · 9000, but there was no significant difference between 0 · 20mm and 0 · 25mm Pdet (Pdet = 0 · 5313) among the 5 kinds of nylon fibers (lumps) The smallest, Pdet of 1.00mm is the largest, while the difference of 0.45mm and 0.60mm is not statistically significant, while the difference of 0.45mm is statistically significant with the others. Conclusions The calculation of ROC curves by using ALVIM statistic phantom TRM and obtaining the judgment probability value Pdet is simple and quick, and is worthy of promotion in the evaluation of image quality control in routine clinical work.