Development of a computer controlled fabrication system for interventional magnetic resonance imaging device production

Abstract

Magnetic Resonance Imaging (MRI) is a promising candidate against X-Ray uoroscopy for interventional cardiovascular procedures due to its ionizing radiation free mechanism and superior soft tissue contrast. However, Intervent onal MRI f eld lacks of dedicated clinical grade MRI safe and visible devices. Aim of this thesis study is to design and develop a Computer Numerical Control (CNC) based 4-axis conductive ink dispenser system for developing low pro le "active" interventional devices for cardiovascular procedures under MRI. The proposed 4 axis CNC controlled dispenser system allows to form three dimensional receiver antenna con gurations automatically onto non-planar catheter shaft surfaces. The developed system decreases the process time and increases the repeatability signi cantly compared to alternative lithography based techniques also used for low pro le active device development. The validation and calibration test results showed that the motion control system works within tolerance of 3.1 m and the dispenser unit works with more than %90 accuracy during several trials. As a part of this thesis study, a resonator marker on a 6 Fr catheter shaft was designed and formed based on former Electromagnetic (EM) simulation results. The resonator marker is basically an LC tank circuit incorporating a solenoid coil and a capacitor. It is used to visualize the distal tip of a 6Fr catheter under 1.5T MR systems. The impedance and resonant frequency of resonant marker were measured with a vector network analyzer and necessary modi cations were made via copper electroplating until the resonant marker is tuned to 63.66 MHz. The visibility and RF induced heating tests were performed successfully for prototype marker device under MRI.