The School of Electrical Engineering and Computer Science, The University of Queensland, St. Lucia, QLD 4072, Australia.
The School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia.
Biosensors (Basel). 2024 Jan 9;14(1):32. doi: 10.3390/bios14010032.
Non-invasive deep brain stimulation using transcranial magnetic stimulation is a promising technique for treating several neurological disorders, such as Alzheimer's and Parkinson's diseases. However, the currently used coils do not demonstrate the required stimulation performance in deep regions of the brain, such as the hippocampus, due to the rapid decay of the field inside the head. This study proposes an array that uses the cone coil method for deep stimulation. This study investigates the impact of magnetic core and shielding on field strength, focality, decay rate, and safety. The coil's size and shape effects on the electric field distribution in deep brain areas are also examined. The finite element method is used to calculate the induced electric field in a realistic human head model. The simulation results indicate that the magnetic core and shielding increase the electric field intensity and enhance focality but do not improve the field decay rate. However, the decay rate can be reduced by increasing the coil size at the expense of focality. By adopting an optimum cone structure, the proposed five-coil array reduces the electric field attenuation rate to reach the stimulation threshold in deep regions while keeping all other regions within safety limits. In vitro and in vivo experimental results using a head phantom and a dead pig's head validate the simulated results and confirm that the proposed design is a reliable and efficient candidate for non-invasive deep brain magnetic stimulation.
经颅磁刺激的非侵入性深部脑刺激是一种有前途的治疗几种神经疾病的技术，如阿尔茨海默病和帕金森病。然而，由于头部内部场的快速衰减，目前使用的线圈在大脑深部区域，如海马体，不能展示出所需的刺激性能。本研究提出了一种使用锥形线圈方法进行深部刺激的阵列。本研究调查了磁芯和屏蔽对场强、聚焦性、衰减率和安全性的影响。还研究了线圈的大小和形状对深部脑区电场分布的影响。使用有限元方法计算了真实人头模型中的感应电场。模拟结果表明，磁芯和屏蔽增加了电场强度并增强了聚焦性，但没有改善场衰减率。然而，可以通过增加线圈尺寸来降低衰减率，但这会牺牲聚焦性。通过采用最佳的锥形结构，所提出的五线圈阵列降低了电场衰减率，使深部区域达到刺激阈值，同时使所有其他区域都在安全范围内。使用人头模型和死猪头的离体和在体实验结果验证了模拟结果，并证实了所提出的设计是一种可靠和有效的非侵入性深部脑磁刺激候选方案。
