Development of precise 3D temperature rise estimation method and measurement system caused by ultrasonic irradiation

对于新的成像系统，重要的是确保由超声引起的温升的安全性，因为诸如弹性成像的新系统使用的辐射力比传统系统需要更高的超声。研究了拟血液循环系统仿组织体模的精确三维热分布期望方法。 采用MPI并行编程技术和GPU单元开发了三维FDTD-HCE仿真程序。 用含有石墨等成分的琼脂制作90 mm的立方体体模。 在琼脂模体中，纯水在准血管（塑料管）中流动。体模的声常数和热常数与软组织基本相同。用红外测温仪测量了模型中心截面的温度分布。三维仿真结果与琼脂体模实验结果吻合较好。 结果表明，该方法对热传导分析是有效的。

It is important to assure the safety of temperature rise caused by ultrasound for new imaging system, because new system such as an elasticity imaging used radiation force requires higher ultrasound than the conventional system. We studied about the precise 3D-thermaldistribution expectation method for the tissue mimicking phantom with quasi blood-circular system. The 3D FDTD-HCE simulation program using MPI parallel programing technique and some GPU units was developed. The cubic phantom in 90mm was made with agar that had some components such as graphite. The pure water was flowing in the quasi blood vessel (plastic tube) in the agar phantom. Acoustic and heat constants of phantoms were almost the same as that of soft tissue. Temperature distributions at the center section of phantoms were measured by infrared thermometer. The 3D simulation results agreed well with experiment of agar phantom. It shows that proposed method has the validity for the thermal conduction analysis.