能谱CT成像中测量位置与校正系数的关系

摘要

背景：能谱CT成像研究中，扫描参数的选择是大多数研究者容易考虑的，而针对测量位置对成像的影响往往被忽略。实际测量发现不同的测量位置对测量结果有显著影响。通过大量数据的测量和数学模型可以对测量位置带来的结果差异进行校正，结果与真实数据吻合度较高。目的：探讨能谱CT成像不同测量位置对测量结果的影响，优化校正系数。方法：采用GE公司标准水模，5个扫描参数有序组合，测量552组数据。测量方法分为大小两个测量范围，分别为ROI1和ROI2。水模上选取中心、上北、下南、左西、右东10个测量点测量CT值。归类筛选相同测量序列的ROI1和ROI2测量数据。建立数学模型，利用概率统计分析法，校正位置系数，建立校正函数，绘制实验模拟曲线。结果与结论：①能谱CT水模成像ROI1方法测量好于ROI2方法测量；②不同的扫描序列测量结果不同。相同的扫描序列，不同的测量位置对测量结果有显著影响，且不同位置影响效果不同；③但通过建立数学模型，采用统计分析法可以获得不同位置的校正函数；④结果提示，通过能谱CT扫描参数的理论模型和实验数据结合分析，可以校正位置系数，优化测量结果。%BACKGROUND:In spectral CT imaging study, the selection of scanning parameters is considered by most researchers, but the effects of measuring position are often overlooked. Actual measurement found that different measurement location had significant impact on the result of the measurement. Through measurement and mathematical model of a large amount of data, we can correct the measurement results of different location. The results with real data alignment are higher. OBJECTIVE:To explore effects of different measuring positions on results in spectral CT imaging, and to optimize correction coefficients. METHODS:GE standard water phantom was applied to orderly obtain 5 combined scanning parameters with 552 groups of data. Size measurement method was divided into two measuring range:ROI1 and ROI2. We selected 10 points to measure CT value, including Center, North, South, West and East. The measurement data of ROI1 and ROI2 were classified and screened based on the same sequence. Mathematical modeling and probability statistics analysis were used to optimize correction coefficient, get calibration function and draw experimental simulation curve. RESULTS AND CONCLUSION:(1) Measuring methods of ROI1 were superior to the ROI2’s on water phantom in spectrum CT. (2) To different scanning sequences, the measuring results were different. To the same scanning sequences, the measurements for different positions on water phantom in spectrum CT had remarkable influence on the measuring results, which varied from points to points. (3) Through setting up mathematical modeling, using method of statistical analysis, we could get the correction function on different measuring positions. (4) Above results confirmed that compared with the theoretical model and the experimental data of spectral CT scanning parameters, the coefficients of position can be adjusted, which can optimize the measuring results.