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

对于新的成像系统来说，确保超声温升的安全性是非常重要的，因为新的成像系统，如使用辐射力的弹性成像系统，对超声的要求比传统系统更高。针对具有准血液循环系统的组织模拟体模，研究了精确的三维热分布期望方法。利用MPI并行编程技术和部分GPU单元开发了三维FDTD-HCE仿真程序。90 mm的立方体模型是用含有石墨等成分的琼脂制成的。琼脂模型中的准血管(塑料管)中流动着纯净水。体模的声学和热常数与软组织的声学和热常数基本相同。用红外测温仪测量了体模中心截面的温度分布。三维模拟结果与琼脂模型实验结果吻合较好。结果表明，所提出的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.