Investigation Of Non-Contact Measurement Method On Brain Edema And Hematoma

At present, there are two main categories of the clinical medicinal imaging technology. One is the structural imaging, and the other is the functional imaging. The former includes X-ray, CT, MRI and ultra-sound imaging. And the latter includes the radionuclidic imaging(PET), fMRI, Magnetoencephalography(MEG) and EIT. After analyzing and comparing the characteristics of these two kinds of imaging technologies, this article points out the disadvantages of the structural imaging, draws a conclusion that the replacement of the structural imaging by the functional imaging is inevitable. But the existing functional imaging apparatuses can not satisfy the need of an equipment which is portable, routine ongoing and can be used by bedside. In the article, we developing a new functional imaging technology named Magnetic Induction Imaging(MIT) to fit the desire. Firstly The research status and the existing problems of magnetic induction imaging are summarized in details. Then, the principles of three different kinds of MIT methods are presented. And the electromagnetic background of the chosen method is analyzed, upon which, the feasibility and the superiority of the MIT method is proved in theory. In the study, we focuses on the development of the measurement hardware. On the base of analysis the characteristic of the weak signal induced by the organism and tissue, the idea of capturing the signal's relative change is obtained. A measurement system is designed, which consist of a sin signal source; a power amp, driving the excitation coil of the sensor; a sensor, transmitting alternating primary magnetic field and picking up the secondary magnetic signal; a nulling circuit, providing a nulling reference signal; a lock-in amp, picking up the wanted signal; an A/D converter; a controller, controlling the whole system; a computer, collecting data and imaging. A phantom is designed to simulate the brain hematoma, and the experiment is operated on it. The conclusion is that the system we developed can distinguished the hematoma area from the normal brain tissue. Finally, the future work of this MIT system is discussed.