学位論文

ファンビームSPECTにおける空間分解能の改善

Improvement　of　the　spatial　resolution in　a　fanbeam　SPECT

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

A fanbeam collimator is sometimes used in the single photon emission CT (SPECT) system to improve the spatial resolution of a reconstructed image. This collimator introduces an aperture effect as well as a parallel-hole collimator, however the distortion is not so much compared with the parallel hole collimator. As a result, the aperture effect is usually ignored in clinical studies. The purpose of the study is to develop a new aperture correction method of the fanbeam collimator. In a fanbeam collimator, the effect of the collimator aperture depends on the hole position in the detector, and so we modeled the aperture effect with an asymmetric Gaussian function. We corrected the aperture effect in the process of an iterative image reconstruction with the OS-EM method, in which we calculated projection data by multiplying the ideal projection data with an asymmetric Gaussian function. To evaluate the validity of our proposed method, we used clinical data. The results showed that the spatial resolution of corrected images was much improved with the proposed method, and the validity of the proposed method was confirmed.

Thesis