School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, 06974, South Korea.
Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, 48513, South Korea.
Biomed Eng Online. 2019 Jun 26;18(1):77. doi: 10.1186/s12938-019-0697-3.
Temperature monitoring during high-intensity focused ultrasound (HIFU) therapy on tissue is essential to regulate the degree of thermal coagulation and to achieve the desired treatment outcomes eventually. The aim of the current study was to design and investigate the feasibility of a proportional-integral-derivative (PID) temperature controller-integrated portable HIFU driver for thermal coagulation.
A portable HIFU driver was designed and operated at a maximum output voltage of 50 V with pulse-width modulation signals at 2 MHz. The temperature of ex vivo bovine liver tissue was monitored using a K-type thermocouple during the 2-MHz HIFU exposure.
The tissue temperature was maintained at 60 °C using a PID controller-integrated HIFU driver that modulated the output voltage during the 300-s HIFU exposure. The ex vivo testing demonstrated that the tissue temperature at the focal point approached the chosen temperature, i.e., 60 °C, within 70 s. The temperature was maintained with a deviation of less than 4 °C until the HIFU driver voltage was turned off at 300 s.
The designed PID controller-integrated HIFU driver can be used as a small portable tool to regulate the tissue temperature in real time and achieve thermal coagulation via HIFU sonication.
高强度聚焦超声 (HIFU) 治疗过程中对组织进行温度监测对于调节热凝固程度和最终实现预期的治疗效果至关重要。本研究旨在设计并研究一种集成比例积分微分 (PID) 温度控制器的便携式 HIFU 驱动器，用于热凝固。
设计了一种便携式 HIFU 驱动器，最大输出电压为 50 V，并带有 2 MHz 的脉冲宽度调制信号。在 2 MHz 的 HIFU 辐射过程中，使用 K 型热电偶监测离体牛肝组织的温度。
使用集成 PID 控制器的 HIFU 驱动器将输出电压在 300 s 的 HIFU 辐射过程中进行调制，可将组织温度维持在 60°C。离体测试表明，在 70 s 内，焦点处的组织温度接近所选温度，即 60°C。在 300 s 时关闭 HIFU 驱动器电压之前，温度保持在 4°C 以内。
设计的集成 PID 控制器的 HIFU 驱动器可用作小型便携式工具，实时调节组织温度，并通过 HIFU 超声实现热凝固。
