Trial Projection of High Speed Optical Computed-Tomograph using Large Transmitted Light Image

光学计算机断层扫描（光学CT）被期望提供生理活动和缺陷的具体诊断信息。然而，光在生物组织中的强烈扩散阻碍了投影数据的检测，即光的强度沿直线积分，这是目前用于x射线CT的CT图像重建算法所必需的。目前已经提出了几种检测生物组织中准直线传播光子的方法。在我们之前的研究中，我们研究了利用光偏振提取在扩散介质中沿近直线传播的光分量的方法。采用光偏振法对高散射介质中吸收体的投影数据进行了处理。通过检测保留初始偏振的光子，可以显著抑制由于漫射光引起的投影数据的底电平。利用该方法重建的光学CT图像具有比传统方法更高的特殊分辨率。综上所述，通过对透射光分量的检测，通过抑制漫射光来保留初始偏振，从而提高了光学CT投影数据的对比度。根据该方法测量的投影数据，利用相位调制器重建两个吸收体在75mm厚的测试散射介质（1.2%“脂内10%”水溶液）中的光学CT图像。两个吸收体在CT图像上明显分离，但在总透射强度重建中没有分离。

Optical computed tomography (Optical CT) has been expected to offer specific diagnostics information on the physiological activities and defects. However, the strong diffusion of light in biological tissues hinders the detection of projection data, i. e. the intensity of light is integrated along straight lines, which is necessary for the CT image reconstruction algorithm currently used for x-ray CT.Several methods have been proposed to detect quasi-straightforward-propagating (QSP) photons of the biological tissue. In our previous research, we investigated the method using light polarization to extract light components traveling along a nearly straight line in a diffused medium.A method utilizing light polarization was applied to take the projection data of absorbers in a highly scattering medium. The floor level of the projection data due to diffused light was significantly suppressed by detection of photons which preserved initial polarization. An optical CT image was reconstructed from the projection data taken by this method and exhibited higher special resolution than the image reconstructed from the projection data by conventional method.In summary, it was confirmed that the contrast of projection data for the optical CT was improved by the detection of transmitted light component which preserved the initial polarization as a result of suppression of the diffused light. The optical CT image of two absorbers in the test scattering medium (1.2% aqueous solution of "Intralipid 10%") 75mm thick was reconstructed from the projection data measured by the method using a phase-modulator. The two absorbers were clearly separated in the CT image, but were not separated in that reconstructed from the total transmitted intensity.