Evolution of spatial resolution in breast CT at UC Davis
Evolution of spatial resolution in breast CT at UC Davis
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DOI：
10.1118/1.4915079
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发表时间：
2015-04-01
期刊：
影响因子：
3.8
通讯作者：
Aminololama-Shakeri, Shadi
中科院分区：
文献类型：
--
作者：
Gazi, Peymon M.;Yang, Kai;Aminololama-Shakeri, Shadi
目的：自20世纪90年代末以来，用于乳腺癌筛查的专用乳腺计算机断层扫描（bCT）技术一直是加州大学戴维斯分校的研究重点。先前的研究表明，这种模式的空间分辨率特征的改善与更高的微钙化检测相关，这是一个被认为是bCT潜在限制的因素。本研究的目的是提高空间分辨率，其特征在于调制传递函数（MTF）通过改变扫描仪的硬件组件和operational schema.Methods：四个原型的悬垂几何，锥束乳腺CT扫描仪的设计和开发跨越三代的设计演变。为了提高每一代bCT的系统MTF，对成像组件进行了修改（X射线管和平板探测器），系统几何结构（源到等中心和探测器距离）和图像采集参数（技术因素、投影数量、系统同步方案和机架旋转速度）。不同代bCT系统的表征表明，这些修改导致从第一代到第二代的限制MTF性能提高了188%，从第二代到第三代又提高了110%。在第一代中观察到的方位角方向上的固有分辨率退化通过将采集从连续改变为脉冲X射线采集来校正。利用第三代高分辨率探测器，沿着对系统几何结构和扫描协议进行修改，使极限分辨率提高了125%。通过将探测器合并模式从2x2改变为1x1，获得了额外的39%的改善。结论：这些结果强调了乳腺CT技术在空间分辨率特性方面的进步。脉冲X射线系统、更高分辨率的平板探测器以及改变扫描仪几何结构和图像采集逻辑的组合使用导致MTF显著提高四倍。(C)2015年美国医学物理学家协会。
Purpose: Dedicated breast computed tomography (bCT) technology for the purpose of breast cancer screening has been a focus of research at UC Davis since the late 1990s. Previous studies have shown that improvement in spatial resolution characteristics of this modality correlates with greater microcalcification detection, a factor considered a potential limitation of bCT. The aim of this study is to improve spatial resolution as characterized by the modulation transfer function (MTF) via changes in the scanner hardware components and operational schema.Methods: Four prototypes of pendant-geometry, cone-beam breast CT scanners were designed and developed spanning three generations of design evolution. To improve the system MTF in each bCT generation, modifications were made to the imaging components (x-ray tube and flat-panel detector), system geometry (source-to-isocenter and detector distance), and image acquisition parameters (technique factors, number of projections, system synchronization scheme, and gantry rotational speed).Results: Characterization of different generations of bCT systems shows these modifications resulted in a 188% improvement of the limiting MTF properties from the first to second generation and an additional 110% from the second to third. The intrinsic resolution degradation in the azimuthal direction observed in the first generation was corrected by changing the acquisition from continuous to pulsed x-ray acquisition. Utilizing a high resolution detector in the third generation, along with modifications made in system geometry and scan protocol, resulted in a 125% improvement in limiting resolution. An additional 39% improvement was obtained by changing the detector binning mode from 2x2 to 1x1.Conclusions: These results underscore the advancement in spatial resolution characteristics of breast CT technology. The combined use of a pulsed x-ray system, higher resolution flat-panel detector and changing the scanner geometry and image acquisition logic resulted in a significant fourfold improvement in MTF. (C) 2015 American Association of Physicists in Medicine.