Han Haopeng, Eigentler Thomas Wilhelm, Wang Shuailin, Kretov Egor, Winter Lukas, Hoffmann Werner, Grass Eckhard, Niendorf Thoralf
Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany.
Humboldt-Universität zu Berlin, Institute of Computer Science, 10099 Berlin, Germany.
Cancers (Basel). 2020 Jun 28;12(7):1720. doi: 10.3390/cancers12071720.
Thermal Magnetic Resonance (ThermalMR) leverages radio frequency (RF)-induced heating to examine the role of temperature in biological systems and disease. To advance RF heating with multi-channel RF antenna arrays and overcome the shortcomings of current RF signal sources, this work reports on a 32-channel modular signal generator (SG). The SG was designed around phase-locked loop (PLL) chips and a field-programmable gate array chip. To examine the system properties, switching/settling times, accuracy of RF power level and phase shifting were characterized. Electric field manipulation was successfully demonstrated in deionized water. RF heating was conducted in a phantom setup using self-grounded bow-tie RF antennae driven by the SG. Commercial signal generators limited to a lower number of RF channels were used for comparison. RF heating was evaluated with numerical temperature simulations and experimentally validated with MR thermometry. Numerical temperature simulations and heating experiments controlled by the SG revealed the same RF interference patterns. Upon RF heating similar temperature changes across the phantom were observed for the SG and for the commercial devices. To conclude, this work presents the first 32-channel modular signal source for RF heating. The large number of coherent RF channels, wide frequency range and accurate phase shift provided by the SG form a technological basis for ThermalMR controlled hyperthermia anti-cancer treatment.
热磁共振（ThermalMR）利用射频（RF）感应加热来研究温度在生物系统和疾病中的作用。为了通过多通道射频天线阵列推进射频加热并克服当前射频信号源的缺点，本文报道了一种32通道模块化信号发生器（SG）。该信号发生器围绕锁相环（PLL）芯片和现场可编程门阵列芯片进行设计。为了研究系统特性，对开关/建立时间、射频功率电平精度和相移进行了表征。在去离子水中成功演示了电场操纵。使用由该信号发生器驱动的自接地蝴蝶结形射频天线在体模设置中进行射频加热。使用限于较少射频通道数量的商用信号发生器进行比较。通过数值温度模拟评估射频加热，并通过磁共振测温进行实验验证。由该信号发生器控制的数值温度模拟和加热实验揭示了相同的射频干扰模式。在射频加热时，该信号发生器和商用设备在体模中观察到类似的温度变化。总之，本文展示了首个用于射频加热的32通道模块化信号源。该信号发生器提供的大量相干射频通道、宽频率范围和精确相移为ThermalMR控制的热疗抗癌治疗奠定了技术基础。
