Document Type : Research Article

Authors

School of Computing and Electrical Engineering, Indian Institute of Technology Mandi, Mandi 175005, Himachal Pradesh, India

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. Copyright © 2017 VBRI Press.

Keywords

1.21 March 2006© Copyright 2006, Brandon Disher, Logan
Lenarduzzi, Ben Lewis, and Justin
Leeuwen.
2.
Ghosh S, Thakur V, Choudhury S.R. 2017. Design and simulation
of Helmholtz coil for low cost and low magnetic field MRI system.

EAMC. 22
-24 August 2017, Stockholm, Sweden.
3.T. Tavernier and A. Cotten, “High-versus low-field mrimaging,”
Radiologic clinics of North America, vol. 43, no. 4, pp. 673681,
2005.

4.N. Hayashi, Y. Watanabe, T. Masumoto, H. Mori, S. Aoki, K.
Ohtomo, O. Okitsu, and T. Takahashi, “Utilization of low-field mr
scanners,” Magnetic resonance in medical sciences, vol. 3, no. 1,
pp. 2738, 2004.

5.H. Yoshioka, S. Ito, S. Handa, S. Tomiha, K. Kose, T. Haishi, A.
Tsutsumi, and T. Sumida, “Low-field compact magnetic resonance
imaging system for the hand and wrist in rheumatoid arthritis,”
Journal of Magnetic ResonanceImaging, vol. 23, no. 3, pp. 370
376, 2006.

6.GE Signa Profile 0.2T open MRIFeatures. Obtained from
commercial site.

7.Restrepo-Alvarez, Andres F., Franco-Mejia, Edinson , and Pinedo-
Jaramillo, Carlos R. 2012. Study and analysis of magnetic field
homogeneity of square and circular Helmholtz coil pairs: A Taylor
series approximation. IEEE Computer Society. DOI
10.1109/Andescon.2012.27

8.Zhan, Xiang; Rao, Guyin;Yuan, Jie;Li, Yingying. 2015.
Analysis of the Magnetic Field Homogeneity of Two Different
Geometric Configurations of the Helmholtz Coils by Simulation.
Proceedings of the Second International Conference on
Mechatronics and Automatic Control.pp 743-752

9.
Olivares-Galvan, J.C. ; Leon, F. de; Georgilakis, P.S. ; Escarela-
Perez, R. 2010.
Selection of copper against aluminium windings
for distribution transformers.
IETElectric Power Applications.
DOI: 10.1049/iet-epa.2009.0297

10.Guo-jun, HU.;Yu-hua, PENG; Wei, ZHAO; Xiao-ying,TANG;
2006. Gradient Coil Design in Permanent Magnet MRI.
Proceedings of 19th International Workshop on Rare Earth
Pennanent Magnets & their Applications.

11.Hidalgo-Tobon, S.S. 2010. Theory of Gradient Coil Design
Methods for Magnetic Resonance Imaging. Concepts in Magnetic
Resonance Part A, Vol. 36A(4) 223242 (2010).

DOI:10.1002/cmr.a.20163

12.
Collins, Christopher M. ; Li, Shizhe ; Yang, Qing X. ; Smith,
Michael B. ; 1997. A Method for Accurate Calculation of B1

Fields in Three Dimensions. Effects of Shield Geometr
y on Field
Strength and Homogeneity in the Birdcage Coil. Journal of

Magnetic Resonance 125, 233
241. Article No. MN971136
13.
Collins, Christopher M.; Smith, Michael B.; 2001. Signal-to-Noise
Ratio and Absorbed Power as Functions of Main Magnetic Field

Stren
gth, and Definition of “90°” RF Pulse for the Head in the
Birdcage Coil. Magnetic Resonance in Medicine 45:684
691.
14.Lang, Michael; 2011. Building a Birdcage Resonator for Magnetic
Resonance Imaging Studies of CNS Disorders.