Radio Frequency Impedance Mapping for Medical Imaging

描述(由申请人提供)： 射频阻抗映射(RFIM)是一种新的医学成像方式。RFIM的成像强度是基于体内组织的局部电学性质(即电导率和介电常数)。由于这些属性在不同组织之间差异很大，尤其是在正常组织和恶性组织之间，基于这些属性的图像应该具有重要的诊断价值。潜在的临床应用包括癌症检测和对心肌缺血、脑水肿和扩散性抑郁症等情况的成像。在RFIM成像中，大量的射频线圈(如磁共振成像中使用的)被放置在患者身上。阵列的阻抗矩阵(或S参数)的测量被用来推导出约束患者身体局部电特性的方程系统。然后求解这些方程以获得图像。患者没有暴露在电离辐射或高水平的射频功率中。RFIM的前期工作包括数值模拟和实验工作。模拟表明，RFIM能够产生准确的、全三维的内部解剖图像。早期的实验结果已经开始证实这一点。 拟议的项目将包括分阶段开发RFIM成像系统原型。将对原型进行测试，以确定RFIM的总体可行性，包括可实现的分辨率、重建精度以及对电导率和介电常数中类似肿瘤的变化的敏感性的测试。研究结果将使早期评估RFIM的可行性，原型将作为未来设计的起点。RFIM的成功实施将为组织介电特性的测量提供一种新的、潜在的可靠技术。此外，RFIM是高度非侵入性的，RFIM成像系统可能既便宜又易于携带。

DESCRIPTION (provided by applicant): Radio frequency impedance mapping (RFIM) is a proposed new medical imaging modality. Image intensity in RFIM is based on the local electrical properties (namely conductivity and permittivity) of tissues inside the body. Since these properties vary widely between different tissues and notably, between normal and malignant tissues, images based on these properties should have significant diagnostic value. Potential clinical applications include cancer detection and imaging of conditions such as myocardial ischemia, cerebral edema, and spreading depression. In RFIM imaging, a large array of radio frequency coils (such as are used in magnetic resonance imaging) are placed on the patient. Measurements of the impedance matrix (or S parameters) of the array are used to derive a system of equations that constrain the local electrical properties of the patient's body. These equations are then solved to obtain an image. The patient is not exposed to ionizing radiation or high levels of radio frequency power. Preliminary work on RFIM has included both numerical simulations and experimental work. The simulations indicate that RFIM is capable of producing accurate, fully three-dimensional images of internal anatomy. Early experimental results have begun to confirm this. The proposed project will involve staged development of a prototype RFIM imaging system. The prototype will be tested to determine the overall feasibility of RFIM, including tests of the achievable resolution, reconstruction accuracy, and sensitivity to tumor-like variations in conductivity and permittivity. Results from the study will enable early assessment of the feasibility of RFIM, and the prototype will serve as a starting point for future designs. Successful implementation of RFIM will provide a new and potentially robust technique for measurement of tissue dielectric properties. Furthermore, RFIM is highly non-invasive and RFIM imaging systems are likely to be both inexpensive and easily portable.