Design and fabrication of fiber optic integrated sensor microsystem for interventional medical devices

Abstract

In this thesis, there is presented the design, fabrication and characterization of a medical device prototype for real time monitoring of pressure, temperature and localization information for Magnetic Resonance Imaging (MRI) supported interventional radiological applications. The system allows to determine the position of the medical device used in surgery, as well as environmental conditions in real time by combining ber optical components with micro electro mechanical system (MEMS) sensors, fabricated on an inner diameter of 2.2 mm platform. The system mainly consists of localization, temperature and pressure sensors, where each component takes measurement optically, and transmits data in the same way. The localization detection is realized due to the observation of Magneto Optical Kerr E ect (MOKE), which is a method to measure the magnetization of the sample surface by the change in the polarization of the light. In the controllable magnetic eld area, which is created by gradient eld, the precision is reported for steel grade 430 as 0.475 mm and for Fe2O3 as 4.44 mm. Ambient temperature sensing is based on absorption change in semiconductor due to variations of energy bandgap of a GaAs sample with temperature. Incident light, at a speci c wavelength, on the GaAs is re ected back with the temperature change signature. The sensitivity of the sensor is reported as 0.494 nm/ C. Lastly, the environmental pressure change with respect to chamber pressure of the metallic membrane is measured interferometrically. Among di erent designs, the best sensitivity is reported as 1.456 mV/mmHg by 200 m diameter sized sensor.