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University of Wisconsin – Madison Department of Biomedical Engineering BME 200/300 – Design MRI Gradient Coils Mid-Semester Report Neal Haas - BSAC Peter Kleinschmidt – Leader Anne Loevinger - Communicator Luisa Meyer - BWIG 10/20/2008 Contents Table of Figures 2 Abstract 3 Problem Motivation 3 Background 5 Design Specifications 6 Common Coil Designs 7 Product Development 8 Simulation 9 Validation of Computations 10 Future Work 11 References 12 Appendix A – Product Design Specifications 13 Appendix B – Biot-Savart Script 15 Table of Figures Figure 1 – Coordinate system for the MRI 1 Figure 2 – The Helmholtz Coil Pair 1 Figure 3 – The Magnetic Field Created by Helmholtz Coil Pair 1 Figure 4 – The Maxwell Coil Pair and Direction of Current Flow 1 Figure 5 – The Golay Coil Pairs 1 Figure 6 – Preliminary Design concept for probe stand. 1 Figure 7 – Final design of Probe stand. 1 Abstract As part of a broader goal to develop novel applications of Magnetic Resonance Imaging (MRI), a low-cost and modular MRI system is currently being developed. One component of this project is the design, construction and testing of gradient coils to function within the system. In addition to background on MRI, several common gradient coil designs are presented within this report, and serve as a basis for development. A simulation script has been developed to approximate magnetic field strengths produced by a given coil design. This will aid in formulating a coil design that produces a magnetic field that varies linearly along its axis. Finally, designs for a testing environment have been developed to aid in the design of the coils, as well as to validate the simulations. Future work will include construction of the testing apparatuses, validation of the simulation script, and preliminary construction and testing of one set of gradient coils. Problem Motivation Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging technique that creates cross-sectional ima