摘要
目的:根据圆的内接正多边形顶点的计算公式,提出一种对使用DoseLab软件检测CT图像均匀性的改进方法。方法:根据DoseLab中原正方形感兴趣区域(ROI)的顶点坐标,由圆的内接正多边形顶点的计算公式,计算得到改进后正十六边形ROI的顶点坐标,并计算原正方形ROI和改进后正十六边形ROI的面积。使用DoseLab对2014年1月—2015年12月共24次月检结果中Catphan CTP486模块图像进行分析,比较程序改进前后的CT值及图像均匀性的差异。结果:对改进前后的正方形和正十六边形的ROI进行分析比较:单个ROI的面积分别为4 cm^2和3.06 cm^2;中心ROI的平均CT值()分别为(12.790±0.930)HU和(12.723±0.927)HU,有统计学差异(P<0.05);CT图像均匀性值分别为(0.372±0.272)HU和(0.366±0.264)HU。结论:DoseLab软件可自动选择ROI的位置和尺寸,结合改进程序,ROI的形状和面积更加接近圆形,图像均匀性的测量方法和结果更加符合国际电工委员会(IEC)的标准。
Objective： To propose a method of program improvement in DoseLab to test the CT image uniformity, according to the vertex formula of inscribed regular polygon of a circle. Methods： The vertex coordinates of regular hexadecagon ROI were obtained from the vertex formula of inscribed regular polygon of a circle and the vertex coordinates of previous square ROI. The ROI areas before and after the improvement were calculated to make comparison. The difference of CT number and image uniformity before and after the improvement was evaluated by analyzing the Catphan CTP486 module of 24 months＇ resnlts from January 2014 to December 2015 tested by DoseLab. Results： Analysis of ROI before and after the improvement was performed： the single ROI areas were 4 cm^2 and 3.06 cm^2 respectively; the mean CT number of center ROI （x） were （12.790 ± 0.930） HU and （12.723 ± 0.927） HU respectively, the results remained statistically significant （P〈0.05）; the image uniformity values were （0.372 ± 0.272） HU and （0.366 ± 0.264） HU respectively. Conclusion： The DoseLab could choose the sizes and locations of the ROIs automatically. Combined with the improved program, the shape and area of ROi are more closer to the those of circle, and the measurement method and result of CT image unifirmity comply better with those of the IEC standards.
出处
《中国数字医学》
2017年第12期57-60,共4页
China Digital Medicine
基金
南京市医学科技发展资金“青年工程”人才培养专项经费资助(编号:QRX11033)~~
