Mackenzie Alistair, Eales Timothy D, Dunn Hannah L, Yip Braidley Mary, Dance David R, Young Kenneth C
National Coordinating Centre for the Physics in Mammography (NCCPM), Level B, St Luke's Wing, Royal Surrey County Hospital, Guildford GU2 7XX, UK.
Department of Physics, University of Surrey, Guildford GU2 7XH, UK.
Phys Med. 2017 Jul;39:137-146. doi: 10.1016/j.ejmp.2017.06.019. Epub 2017 Jun 21.
To demonstrate a method of simulating mammography images of the CDMAM phantom and to investigate the coefficient of variation (CoV) in the threshold gold thickness (t) measurements associated with use of the phantom.
The noise and sharpness of Hologic Dimensions and GE Essential mammography systems were characterized to provide data for the simulation. The simulation method was validated by comparing the t results of real and simulated images of the CDMAM phantom for three different doses and the two systems. The detection matrices produced from each of 64 images using CDCOM software were randomly resampled to create 512 sets of 8, 16 and 32 images to estimate the CoV of t. Sets of simulated images for a range of doses were used to estimate the CoVs for a range of diameters and threshold thicknesses.
No significant differences were found for t or the CoV between real and simulated CDMAM images. It was shown that resampling from 256 images was required for estimating the CoV. The CoV was around 4% using 16 images for most of the phantom but is over double that for details near the edge of the phantom.
We have demonstrated a method to simulate images of the CDMAM phantom for different systems at a range of doses. We provide data for calculating uncertainties in t. Any future review of the European guidelines should take into consideration the calculated uncertainties for the 0.1mm detail.
演示一种模拟CDMAM体模乳腺X线摄影图像的方法，并研究与该体模使用相关的阈值金厚度（t）测量中的变异系数（CoV）。
对Hologic Dimensions和GE Essential乳腺摄影系统的噪声和清晰度进行表征，以提供模拟数据。通过比较三种不同剂量下CDMAM体模的真实图像和模拟图像以及两个系统的t结果，验证了模拟方法。使用CDCOM软件从64幅图像中的每一幅生成的检测矩阵被随机重采样，以创建512组8幅、16幅和32幅图像，以估计t的CoV。使用一系列剂量的模拟图像集来估计一系列直径和阈值厚度的CoV。
在真实和模拟的CDMAM图像之间，未发现t或CoV有显著差异。结果表明，估计CoV需要从256幅图像中进行重采样。对于体模的大部分区域，使用16幅图像时CoV约为4%，但对于体模边缘附近的细节，CoV超过其两倍。
我们演示了一种在一系列剂量下为不同系统模拟CDMAM体模图像的方法。我们提供了计算t不确定性的数据。欧洲指南未来的任何审查都应考虑0.1mm细节的计算不确定性。
