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

超声CT法测量人体模型温度分布

基本信息

批准号：
07650273
负责人：
NAWATA Yutaka
金额：
$ 1.66万
依托单位：
Yatsushiro National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650273/
关键词：
Measurement Ultrasonic Wave Heat Transfer Computed Tomography Temperature Distribution Living Body

项目摘要

It has been getting importance to measure the interior temperature in the body since hyperthermia appeared in treatment of cancer. In this treatment, it is important to hold the temperature of tumor over 42.5ﾟc to avoid the heat damage of normal tissue. We anticipate a technology measuring indirectly the interior temperature distribution of the arbitrary transverse section in the body and displying the image for monitoring.In this paper, An ultrasonic CT (Computed tomography) method is researched for measuring indirectly the interior temperature distribution from a series of sound projections that are taken at several different orientations relative to a phantom body. Ultrasonic CT is mainly one of the methods getting the transverse image of the body as the same as X-ray CT.But it has the advantage of simpler instrument because it doesn't have the radiation injury like X-ray CT.We can obtain the sound speed distribution within the object by measuring the arrival time of sound wave with … More ultrasonic CT.The purpose of this study is to develop the method measuring indirectly the interior temperature distribution of an object from the difference of sound speed between heating and non-heating, using the characteristics the sound speed depends on the temperature.First, we compare three reconstruction algorithms to minimize a number of required projections. Next, we make an experiment about the dependence of temperature on sound speed in water and get a relation between the temperature and the sound speed in water. Then, phantoms made of agar are placed in a water bath, and a series of sound projections is measured when a pair of ultrasonic detectors are both translated and rotated. We can obtain the temperature distribution in phantom with accuracy 0.1ﾟc by subtracting the sound distribution when non-heating from one when heating. The structure differences of watery tissue like blood, musculature, and the viscera do not effect on the measurement of the temperature distribution, because it is deleted by subtracting the sound speed when non-heating from the sound speed when heating.Lastly, We make an experiment in which there is a bone crossing the transverse section of the ultrasonic measurement. When bone or gas is in the area of measurement, the projections include a data missing part. As a result of the experiment, we could obtain approximately the reconstructed image by the modification of the projections, and the temperature distribution, too, if the missing part is small. But we can not calculate precisely the temperature distribution, if the missing part is large. Less

自从热疗在癌症治疗中出现以来，测量体内温度就变得越来越重要。在这种治疗中，重要的是将肿瘤的温度保持在42.5 ℃以上，以避免正常组织的热损伤。本文研究了一种利用超声CT（Computed Tomography）技术，从相对于体模的不同方位拍摄的一系列声投影来间接测量体内温度分布的方法。超声CT与X射线CT一样，主要是获得人体的横向图像的方法之一，但它具有仪器简单的优点，因为它不像X射线CT那样具有辐射损伤。我们可以通过测量声波的到达时间来获得物体内部的声速分布，并通过测量声波的到达时间来获得物体内部的声速分布。 ...更多信息本文利用超声CT的声速随温度变化的特点，提出了一种利用加热和不加热时声速的差异间接测量物体内部温度分布的方法，首先比较了三种重建算法，以减少所需的投影次数。其次，我们做了一个关于水中声速与温度关系的实验，得到了水中声速与温度的关系。然后，将琼脂制成的模型置于水浴中，当一对超声探测器平移和旋转时，测量一系列声音投影。我们可以通过从加热时的声音分布中减去非加热时的声音分布来获得精度为0.1 μ c的体模中的温度分布。由于加热时的声速减去非加热时的声速，从而消除了血液、肌肉组织、内脏等含水组织的结构差异对温度分布测量的影响。最后，进行了一个横截面上有骨的超声测量实验。当骨骼或气体在测量区域中时，投影包括数据缺失部分。实验结果表明，通过对投影的修正，可以近似地得到重建图像，并且在缺失部分较小的情况下，也可以得到温度分布。但是，如果缺少的部分很大，我们就不能精确地计算温度分布。少