強い散乱体の光CTシミュレーション : 第2報,ファンビーム方式

Optical-CT (Computed Tomography) imaging of living bodies poses the difficulty caused by strong scattering of light by tissues. In our previous paper, time-resolved spectroscopy was shown to have potential for realization of optical-CT imaging. In this second paper, it is shown that utilization of the characteristics of strong scattering makes fan-beam-type optical-CT imaging possible. The Monte Carlo method is employed to simulate the strongly scattering and weakly absorbing media. Hybrid scattering calculation is proposed to simulate the highly forward-directed scattering to avoid unrealistic sharp peaks at the shortest time of flight observed when only isotropic scattering approximation is employed. The temporally extrapolated absorbance method is employed for the object and reference cylinder, as in the previous paper. Fan-beam-type optical-CT imaging is numerically shown to be capable of reconstructing an image of the difference in the absorption coefficient with satisfactory accuracy and spatial resolution.