Design and characterization of the power supply unit and driver blocks of a MOS based localization system for MRI

Abstract

MRI is an imaging technique frequently used in medicine and related elds. Advantages associated with it are the acquisition of images with higher contrast and exibility in computational environment. MRI is also desirable due to its safety as it does not emit ionizing radiation, thus while potentially allowing for longer imaging periods when necessary. Such a need may arise especially in conjunction with the catheter based medical operations, during which the movement of the catheter has to be tracked over its course. Advantages of MRI make it an ideal candidate for this, although MRI-based tracking can be problematic when metal parts or cables are used. Due to presence of magnetic resonance, these components may lead to image distortions and RF-induced heating around them. This thesis presents the characterization and testing of a micro-system, using optical transmission, which is designed previously for catheter localization. After that, it continues by proposing an improved version of the said system with an altered power supply unit and output signal driver. The system consists of an RF IC designed UMC 0.18 m triple well CMOS technology and other optoelectronic components. The IC is composed of an RF receiver block, collecting MRI signals via a coil antenna of diameter 2 mm, and an intermittently operating optical power supply unit. Power is transmitted as a laser beam of wavelength 660nm and the localization information is sent via a ber-coupled LED of wavelength 1310 nm. The modi ed version would use an array of MEMSbased resonators to re ect an incoming beam in order to transmit the localization information. The new design would also feature continuous operation, in addition to the previous intermittent scheme.