Measurement of Temperature Distribution in Phantom Body by an Ultrasonic CT Method

本研究首先对三种常用的重建算法进行了比较研究，以最小化所需的投影数。其次，利用超声波测量了不同水温下水中的声速，得到了声速与水温的关系。此外，我们利用超声CT和热电偶方法测量了占人体90%的水的温度分布。将CT算法重建的温度分布与热电偶测量的温度分布进行了比较。最后，我们进行了琼脂体模体温度分布的测量实验。由于我们不知道真实的温度分布，所以我们不能准确地得出模型中温度分布的准确性。然而，我们可以从水中温度分布的测量结果中估计出，在均匀材料中，准确度可以接近0.1‰。超声CT法在非均匀材料中的应用，需要从测量和计算的角度进行进一步的研究。

In this study, first, a comparative study of three popular reconstruction algorithms was made to minimize a required number of projections. Second, we measured the sound speed in water at several water temperatures by ultrasonic wave, and obtained the relationship between the sound speed and the temperature of water. Further, we measured the temperature distribution of water, which occupied 90% of a human body, by means of the ultrasonic CT and the thermocouple method. The temperature distribution reconstructed by a CT algorithm was compared with the distribution measured by thermocouple. Finally, we made an experiment on the measurement of temperature distribution in phantom objects made of agar.We can not conclude exactly the accuracy of temperature distribution in the phantom, because we do not know the true temperature distribution. However, we can estimate from the measurement results of the temperature distribution in water that the accuracy could be approximately 0.1ﾟC in the homogeneous materials. The ultrasonic CT method in the inhomogeneous materials is required to be investigated further from the view points of the measurement and the calculation.