CMOS based optoelectronic catheter localization system for magnetic resonance imaging environment

Abstract

The use of minimally invasive medical techniques has greatly reduced risks to patients and has increased our understanding of how the body works. Detection of catheters is one of the most important tasks in these techniques. Magnetic resonance imaging provides a safe environment for catheter driven operations. On the other hand, implementation of catheter localization architectures are problematic due to the impossibility of long conductor usage due to RF induced heating problem in MRI environment. There is a need for devices that use transmission systems other than electrical for realizing catheter driven operations in MRI environment. This thesis presents design and implementation of a micro-system that uses optical transmission for localization of catheters in MRI environment. The micro-system is composed of a radio frequency (RF) integrated circuit (IC) designed in 0.18 m triple well CMOS technology and optoelectronic components. The RF integrated circuit covers an RF receiver architecture and an optical power supply unit that provides power to the receiver. The power to the system is served by a laser with a wavelength of 660 nm. RF receiver is connected to a micro-coil antenna with a diameter of 2 mm, and it can transmit very low powered magnetic resonance signals to the external environment via a ber-coupled LED with a wavelength of 1310 nm. The external optical receiver and signal processing unit detect the location of the catheter using the frequency information of the received signal. The implemented system is tested successfully in 3T MRI environment. The tests show that the system has 350 m spatial resolution, which proves that the implemented system can be used for the catheter driven minimally invasive operations.