Noise-Isolating Capsule for Small-Animal fMRI Research

描述(由申请人提供)：该项目的长期目标是提供一种胶囊，使功能磁共振成像(FMRI)能够方便地在实验动物身上进行，而不会使这些动物受到与MRI设备产生的声学噪声相关的压力。这种胶囊将有助于对动物模型进行成像研究，以确定与使用和滥用精神活性物质有关的大脑变化，因为声学噪音应激与这些物质的影响相互作用。一个由透明塑料制成的原理验证胶囊将被建造来容纳一个小型灵长类动物，并适合典型的核磁共振系统。将获得能够在磁共振扫描仪的强磁场中可靠工作的声学测量设备，并对其性能进行验证。初始舱将配备各种声障布置，由双层结构和弹性层组成，顶层为厚层，外部增加吸声层。对于常规扫描和仅在有限频率范围内产生声学噪声的扫描协议，将对这些屏障布置的隔音性能进行测量、分析和优化。将对两个高声衰减的原型胶囊进行详细设计。该设计将考虑到非声学要求，例如需要观察测试对象，需要清洁和消毒胶囊，以及容纳略有不同大小的动物。将进行一项旨在通过主动控制手段提高太空舱隔音性能的初步研究。这项研究将解决传感器和执行器的位置和类型，它们之间的传递函数，以及控制逻辑。

DESCRIPTION (provided by applicant): The project's long-term objective is to provide a capsule that will permit functional magnetic resonance imaging (fMRI) to be carried out on test animals conveniently without subjecting these animals to the stresses associated with the acoustic noise produced by MRI equipment. Such a capsule will facilitate imaging research on animal models to identify brain changes associated with the use and abuse of psychoactive substances, since acoustic noise stress interacts with the effects of these substances. A proof-of-principle capsule of a clear plastic will be built to accommodate a small primate and fit into a typical MRI system. Acoustical measurement equipment that can operate reliably in a MRI scanner's intense magnetic fields will be obtained and its performance will be verified. The intial capsule will be provided with various acoustic barrier arrangements consisting of double-wall structures and resilient layers topped by massive layers, with acoustically absorptive layers added on the exterior. The noise isolating performance of these barrier arrangements will be measured, modeled analytically, and optimized -- both for conventional scanning and for scanning protocols that generate acoustic noise in only limited frequency ranges. Detailed design of two prototype capsules with high acoustic attenuation will be carried out. The design will take account of non-acoustical requirements, such as the need to observe the test subject, the need to clean and disinfect the capsule, and accommodation of animals of slightly different sizes. An initial study aimed at enhancing the capsule's noise isolation performance by active control means will be performed. This study will address sensor and actuator locations and types, the transfer functions between these, and the control logic.