Diagnostic imaging for lung diseases using micro 3D CT image

我们研制了一台微型CT扫描仪的原型系统，它能够对肺标本进行空间分辨率为5 μ m的成像。该原型系统使我们能够精确观察肺部的正常和异常微观结构。本研究的目的是通过建立肺部疾病的三维显微CT图像数据库，分析肺部疾病的特征，建立基于显微CT图像的医学诊断技术。（1）肺标本的测量研究，（2）三维显微CT图像的可视化和数值分析，（3）显微CT扫描系统的性能改进。下文将详细介绍这些部分。(1)It利用原型系统测量微米量级的肺标本需要大约12小时。进行研究的难点之一是通过控制由于X射线管的热引起的机械变化来保持测量系统的稳定状态。在重建显微CT图像时，机械变化导致图像模糊。通过多次测量研究，我们积累了重建肺标本的技术知识，并收集了16个样本。（2）需要开发可视化和分析软件工具，对肺标本进行μ m量级的观察。可视化工具使我们能够以交互方式观察3D肺标本图像，并定量测量形态学特征。这些复杂的工具使得研究肺癌的结构分析成为可能。（3）减少测量时间是显微CT成像要解决的问题之一。为此，我们引入了一个锥束测量系统与平板探测器到微型CT扫描仪。最新原型系统与以前的系统之间的主要区别是，最新原型的X射线管和探测器围绕肺部标本旋转。

We have developed a prototype system of micro CT scanner that is capable of imaging lung specimens with spatial resolution of 5 μ m. This prototype system allows us to precisely observe normal and abnormal microstructures of lung. Our purpose of this study is to establish a medical diagnostic technique based on micro CT images by building 3-D micro CT image database of lung diseases and by analyzing features of them.This study consists. of the following three parts : (1) measurement study of lung specimens, (2) visualization and numerical analysis of 3-D micro CT images, (3) performance improvement of the micro CT scanner system. Those parts are described below in detail.(1)It takes about twelve hours to measure a lung specimen in μ m order by the prototype system. One of difficulties of performing study is to keep stable situation of measurement system by controlling mechanical variations due to heat of the X-ray tube. The mechanical variations result in blurred images when reconstructing micro CT images. Through several measurement studies, we accumulated know-how to reconstruct lung specimens and collected 16 samples.(2)The development of visualization and analysis software tools is required to observe the lung specimens in μ m order. The visualization tools allow us to observe 3D lung specimen images interactively and to measure morphological features quantitatively. These sophisticated tools made it possible to investigate the structure analysis of lung cancers.(3)Reduction of the measurement time is one of problems to be solved for the micro CT imaging. For that we introduce a cone-beam measurement system with a flat panel detector into the micro CT scanner. The main difference between the latest prototype system and previous one is that an X-ray tube and a detector of the latest prototype rotate around a lung specimen.