Tomosynthesis for improved pulmonary nodule detection

描述（由申请人提供）：这些研究的目的是评估数字断层合成是否可以作为常规胸部x线摄影的辅助手段，以提高肺结节的临床检测。数字断层合成通过一系列纵向切片图像提供三维信息，增强了传统的胸部检查。这些切片图像是用传统的x射线管和新型的数字平板x射线探测器从不同角度获得的一组离散投影图像重建的。层析合成图像可以在“虚拟透视”观看环境中逐片观看或作为三维体渲染投影观看。断层合成的诊断优点是利用三维信息，通过消除上覆结构的混淆来提高对肺结节的检测和鉴别。一旦检测到结节，CT仍然是临床检查的金标准，断层合成提供了一种低剂量/低成本的方法来提高初始检测的准确性。在临床上，每当进行数字旁侧胸部检查时，都会获得断层合成图像，但由于侧位图像的曝光减少，因此患者从PA/侧位/断层合成检查获得的总剂量将与传统旁侧胸部检查获得的总剂量相当。预计层析合成对肺结节检测的灵敏度和特异性将比单独的常规胸部x线摄影更高，因此可能导致肺癌的早期检测，成本明显低于低剂量CT。

DESCRIPTION (provided by applicant):The purpose of these studies is to evaluate whether digital tomosynthesis can serve as an adjunct to conventional chest radiography for improving clinical detection of pulmonary nodules. Digital tomosynthesis augments a conventional chest exam by providing three-dimensional information through a series of longitudinal slice images. These slice images are reconstructed from a set of discrete projection images acquired at different angles, using a conventional x-ray tube and a new digital flat-panel x-ray detector. The tomosynthesized images may be viewed slice-by-slice or as a 3-D volume-rendered projection in a "virtual fluoroscopy'' viewing environment. The diagnostic benefit of tomosynthesis is the use of 3-D information to improve detection and discrimination of pulmonary nodules by eliminating the confusion of overlying structures. CT would remain the gold standard for clinical workup once nodules are detected, with tomosynthesis providing a low-dose/low-cost method for improving initial detection accuracy. Clinically the tomosynthesis images would be acquired whenever a digital PNlateral chest exam is taken, but with reduced exposure for the lateral image such that the total patient dose from the PA/lateral/tomosynthesis exam would be about comparable to the overall dose from a conventional PNlateral chest exam. It is anticipated that tomosynthesis will enable higher sensitivity and specificity for pulmonary nodule detection than conventional chest radiography alone, and hence will potentially lead to earlier detection of lung cancer, at a cost significantly less than low-dose CT. This proposal is a competing continuation of a previous study that developed and optimized the tomosynthesis technique. The present study will conduct a clinical evaluation of tomosynthesis for pulmonary nodule detection in a cohort of human subjects with CT-proven nodules. This study will have three parts: (1) an evaluation of tomosynthesis using radiologists as observers, (2) development and evaluation of a computer-aided diagnosis (CAD) method using three-dimensional tomosynthesis data for pulmonary nodule detection, and (3) a measurement of the accuracy with which radiologists can use tomosynthesis to localize the depth and diameter of nodules. The specific aims of the project also include pilot studies to optimize the tomosynthesis method before the large-scale collection of human subject data. These pilot studies will characterize and minimize effects of patient motion, optimize the number of reconstructed planes and patient entrance exposure, and evaluate slice viewing vs volume rendering.