Design and simulation of Helmholtz coil and Maxwell coil for low cost and low magnetic field MRI machine

Abstract

Magnetic Resonance Imaging is a non-invasive technique which basically consists of a main magnet, gradients, radio-frequency transmitter and receiver and scanner. Commercially available MR scanners are quite heavy. However this bio-device can be made low cost, low weight and also low magnetic field. This work proposes the design and development of a low magnetic field MRI scanner of 0.2T magnetic field strength. This design is based on Helmholtz coil as the main magnet. The homogeneity observed within a radius of 15cm was about 2% in a coil of 30cm radius. While at the centre homogeneity was found much better. Strength of 75µT/m gradient magnetic field has been considered for the design. Maxwell coil has been used for longitudinal gradient and Saddle coil has been used for transverse gradient. The resonant frequency was obtained 8.516MHz for a main magnetic field of 0.2T for protons. Simulation results for magnetic flux density norm had been obtained for Helmholtz coil and Maxwell coil depicting the distribution of magnetic flux density. Also weight of the main magnet had been found to be quite less when compared with main magnet that are commercially used.