Tomographic Imaging of Biological Body with Light

With the progress of light sources and detectors, it has become possible to detect the light passed through a living body. The feasibility of an optical CT with a CW light was investigated. The strong scattering from tissues has been identified as a difficult problem to realize the CT imaging of a living body. A technique called “a scattering angle differential technique” has been newly developed to suppress the effect of scattering in the imaging through diffuse media. The effectiveness of this technique was confirmed in the analysis of the spatial resolution of imaging in diffuse media. The effectiveness was demonstrated in the CT imaging of a model phantom. However, it was found in experiments that this technique alone was not effective with a living mouse. The problem was found to be the reflection and the refraction at the air-tissue interface. Another technique called “a contact technique” was newly developed to overcome this problem. A measurement system was developed to use both techniques simultaneously. Using this system, the CT imaging of a mouse abdomen was attempted. Though the spatial resolution was poor, the existence of a liver and kidneys were recognized in the CT image of a living mouse.