Dosimetry and improved targeting for Transcranial Magnetic Stimulation

描述（由申请人提供）：经颅磁刺激（TMS）是一种用于诱导特定脑区神经元去极化的技术。这是通过使用专门设计的线圈探头产生大的脉冲电磁场来实现的。这些诱导场在神经元组织中产生电流，导致神经元去极化。经颅磁刺激是非侵入性的，可快速重复，对研究对象或患者的风险最小。作为一种利用磁感应电流来调节大脑的装置，颅磁刺激在临床环境中的出现似乎比现有的电休克疗法提供了一种更精确的向大脑输送电流的方法。虽然经颅磁刺激已被发现作为一种研究工具和精神疾病的治疗方法具有巨大的潜力，但该技术存在以下问题：(1)靶向能力差（受刺激区域通常包括不需要刺激的大区域）；(2)缺乏适当的方法来定量测量传递给受试者的实际刺激。这两个问题是密切相关的，为了提高TMS装置的瞄准能力，需要对电磁场进行精确的测量。在本提案中，我们的目标是开发一种新的方法来绘制和量化使用磁共振成像（MRI）技术的经颅磁刺激诱发场。此外，我们的目标是开发一种快速的计算算法，以预测个体的刺激场。为了交叉验证的目的，我们将比较我们基于MRI的测量和我们的计算预测。有了这个框架，我们将使用计算模型结合标准的工程优化技术来改进TMS线圈和刺激脉冲的设计。本建议的更广泛的目标是发展一个更区域特异性和可量化的经颅磁刺激系统。从长远来看，我们希望利用这项技术充分了解经颅磁刺激的治疗效果，从而优化治疗参数。我们希望实现的目标能力改进的另一个好处是，我们使用经颅磁刺激作为精神病学和认知心理学研究工具的能力将得到显著提高。

DESCRIPTION (provided by applicant): Transcranial Magnetic Stimulation (TMS) is a technique used to induce neuronal depolarization in specific brain regions. This is achieved simply by generating large, pulsed, electromagnetic fields with a coil probe designed for that specific purpose. These induced fields produce currents in the neuronal tissue that result in neuronal depolarization. TMS is non-invasive, quickly repeatable and the risks to the research subjects or patients are minimal. As a device that uses magnetically-induced electrical currents to modulate the brain, the advent of TMS in the clinical setting appeared to offer a more precise means of delivering current to the brain than the existing electroconvulsive therapies. While TMS has been found to hold great potential as both a research tool and a therapeutic treatment for mental illness, the technology suffers from (1) poor targeting capabilities (the stimulated areas typically include large regions where no stimulation is desired) and (2) the lack of an adequate method to quantitatively measure the actual stimulation delivered to the subject. These two issues are strongly related to each other in that, in order to improve the targeting capabilities of TMS devices, an accurate measurement of the electromagnetic fields is needed. In this proposal we aim to develop a novel methodology to map and quantify TMS induced fields using magnetic resonance imaging (MRI) techniques. Furthermore, we aim to develop a fast computational algorithm that will predict the stimulation fields on an individual basis. We will compare our MRI based measurements and our computational predictions for cross-validation purposes. With this framework in place, we will use the computational model in conjunction with standard engineering optimization techniques to improve the design of TMS coils and stimulation pulses. The broader objective of this proposal is to develop a more region-specific and quantifiable transcranial magnetic stimulation system. In the long term, we hope to use this technology to fully understand the therapeutic effects of TMS and thus be able to optimize therapeutic treatment parameters. An additional benefit of the improved targeting capabilities we hope to achieve will be a significant improvement in our ability to use TMS as a research tool in psychiatry and cognitive psychology.