学位論文

媒質同定を可能にする光子計数形CTの開発

Development of a Photon Counting X-ray CT System for the Material Identification

jpn

2013-03-24

Not Applicable (or Unknown)

2013-03-24

修士(工学)

工学研究科情報電子工学専攻; 指導教授: 尾川浩一

The purpose of our research is to develop a photon counting X-ray CT system for the material identification. We developed a new CdTe detector that was able to measure x-rays with the count rate of 107 counts/sec/m㎡ with four energy windows. The size of a CdTe detector module was 8 x 8 m㎡, and that of a pixel was 0.2 x 0.2 m㎡. The thickness of the detector was 1 mm. The active area of our detector was 8 x 144 m㎡. We evaluated the performance of the photon counting CT images in terms of the accuracy of reconstructed linear attenuation coefficients. In addition, we compared these reconstructed images with those acquired with the energy integration detector with the CdTe semiconductor detector. And we also show the advantages of a photon counting CT system in terms of the enhancement of contrast and the noise reduction. To show these advantages, we conducted some experiments and simulations. The results were shown that our detector could reconstruct linear attenuation coefficients with the error ratio of less than 3 % compared with the theoretical value. And the photon counting CT system has greater contrast and better image quality than the energy integrated one. The photon counting CT system can reduce the dose and use for material identification.

Thesis