Transillumination imaging of biological body using snake photons

为了实现近红外光对生物体的透照成像，发展了一种实现漫反射介质中吸收分布成像的技术。通过本研究，取得了以下成果：(1)通过理论和实验分析，验证了蛇形光子可以通过致密介质发射，而传统的弹道光子技术无法穿透这种致密介质。(2)发展了一种有效地通过厚度为10-20 mm的哺乳动物组织的散射体探测蛇形光子的技术。这项技术是基于超快光脉冲入射输出脉冲形状的时间分辨测量。(3)将上述原理应用于使用连续波光源的简单得多的连续波(CW)测量。(4)新开发的实验系统由蛇形光子探测装置组成，建立了模拟哺乳动物组织光学性质的模型体模和成像系统。(5)在上述实验系统的成像实验中，验证了所提原理的有效性和所开发系统的实用性。(6)将所提出的原理和所开发的系统应用于经皮荧光成像。(7)将扩散近似应用于传输方程，得到了描述密集随机介质中光子传播的解析解。通过本文的研究，给出了蛇形光子透照成像的具体实现方法，并明确了需要解决的问题。

For transillumination imaging of a biological body by near-infrared light, a technique has been developed to realize the imaging of absorption distribution in diffuse scattering medium. Through this study, the following results were obtained.(1)In theoretical and experimental analyses, it was verified that a detectable amount of snake photons is emitted through the dense medium which could not see through with the conventional technique using ballistic photons.(2)A technique has been developed to detect the snake photon efficiently through the scattering object which corresponds to the mammalian tissue with 10-20 mm thickness. This technique is based on the time-resolved measurement of output pulse shape for ultra-fast light-pulse incidence.(3)A new technique has been developed to apply the above principle to the much simpler continuous wave (CW) measurement using a CW light source.(4)An experimental system was newly developed which consisted of a snake-photon detection device, a model phantom to simulate the optical property of mammalian tissue and an imaging system.(5)The effectiveness of the proposed principle and the usefulness of the developed system were verified in the imaging experiment using the above experimental system.(6)The proposed principle and the developed system were applied to the transcutaneous fluorescent imaging.(7)An analytical solution was obtained to describe the photon propagation in a dense random medium by applying the diffusion approximation to the equation of transfer. Using this solution, a technique to improve the transillumination image through a diffusing medium was newly developed.(8)Through this study, a concrete measure was obtained to realize the transillumination imaging using snake photons as well as clarifying the problems to be solved.