Fundamental Study for the Non-Invasive Laser Coagulation Method

为开发无创激光凝固的新方法，从理论到应用进行了一系列的研究。在第一个实验中，测量了激光在组织中的吸收和透明度，以及热传导和扩散系数等热性质，以了解和模拟激光凝固。以猪的肉和组织为测试材料进行了测量。为了验证这种凝固思想的可行性，对激光照射和冷水冷却组织表面时组织内的温度分布进行了理论分析。在理论分析的基础上，以肉类为试材进行了激光辐照实验，并与分析结果进行了比较。实验中，通过改变水温、水流量、激光强度和激光照射时间来考察激光对组织凝固的影响。理论和实验结果吻合较好。在下一阶段，设计并制作了一台手持式混凝装置样机，进行了应用试验。结果表明，该装置可以很好地应用于肉类的凝固。因此，我们进行了动物实验。也就是说，在研究的最后阶段，进行了动物试验，目的是将本方法应用于猪的胃凝固。详细研究了激光照射前后的变化，并测量了凝固区的大小，明确了凝固区大小与激光功率、照射时间等实验参数的关系。为了积累足够的数据并证实本方法的适用性，动物实验仍在进行中。

A serial research from the fundamental to application has been conducted for developing novel method of non-invasive laser coagulation method. In the first experiment, absorption and transparency of laser in tissues and also thermal properties such as heat conductivity and diffusivity are measured for understanding and modeling the laser coagulation. The measurement was made for meats and tissues of the pig as the test material. To confirm the possibility of the present idea of coagulation, theoretical analysis of the temperature distribution in tissues when the laser irradiates and the surface of tissues is cooled by cold water. After the theoretical analysis, experiment of laser irradiation by employing meats as the test material was carried out and compared with the analytical results. In the experiments, water temperature, water flow rate, laser strength and laser irradiation time were changed to investigate the effects for the tissue coagulation. The theoretical and experimental results agree well each other. At the next stage, a prototype handy coagulation devise was designed and produced for the experiment of application. It is found that this device can apply well to the coagulation of meats. So we proceeded to the animal tests. Namely, at the last stage of the research, animal tests were conducted with an aim to apply the present method to the coagulation of stomach of the pig. The changes of the before and after laser irradiation were investigated in detail, and the size of the region of coagulated tissues was measured and the relation of the size to the experimental parameters such as laser power and irradiation time was made clear. With an aim to accumulate sufficient data and confirm the applicability of the present method, the animal tests are still conducting.