Lesson Magnetic Resonance Imaging

Learning Objectives

After this lesson, students should be able to:

• Describe the basics of how magnetic resonance imaging works.
• Describe how the MRI hardware works.
• State and present the connections between an MRI and the magnetic fields studied in this unit.
• Explain safety hazards an MRI machine might present.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

State Standards

Worksheets and Attachments

Introduction/Motivation

Let's refresh our memories about this unit's CHALLENGE QUESTION: A local hospital has just installed a new MRI machine with the capacity to make 3-D images of brains and body parts by placing patients into a strong magnetic field. The hospital wants its staff to understand the risks involved with working near a strong magnetic field and a basic understanding of why those risks occur. Your task is to develop an instructional pamphlet, website or slide presentation explaining the hazards and risks, the physics behind those risks, and recommended safety precautions for staff members to take.

In order to solve the grand challenge and assess MRI safety issues, we must first learn how the MRI machine works. Then we can combine this knowledge with our understanding of magnetic fields to determine the safety issues with the MRI. Safety engineers are always looking for points of weakness in order to eliminate any potential safety hazards so medical equipment is safe for patients and medical staff.

Lesson Background and Concepts for Teachers

Legacy Cycle Information

This lesson is the last lesson in this "legacy cycle" unit. Thus far, students have been presented with information preparing them to solve the challenge question about MRI safety. Lessons 1-9 covered magnetic fields and their properties. In this lesson, students enter the Test Your Mettle phase during which they are challenged to apply the concepts learned to the engineering of an MRI unit, and finally, in the Go Public phase, they are prompted to design a presentation on MRI safety concerns.

Information: Basics of Magnetic Resonance Imaging

Refer to section 5.0 Basic MR Theory in the FDA's MRI Theory Primer for an explanation of the basic functions of MRIs. This explanation applies the concepts students have learned regarding magnetization to the MRI design. You may want to share with students the hazards, safety concerns and reported incidents described in sections 3.0 and 4.0. After a lecture to provide students with the following information, they are ready to Go Public with their challenge question solutions.

Information: MRI Hardware

Hardware Overview: To gain an understanding of the above schematic and exactly how the magnetic field is established, refer to Joseph P. Hornak's hypertext book, The Basics of MRI, specifically paragraphs 2-4 under the Hardware Overview section in Chapter 9: Imaging Hardware at http://www.cis.rit.edu/htbooks/mri/inside.htm.

Magnet: Refer to a clear description of the magnet in Hornak's Chapter 9: Imaging Hardware > Magnet (paragraphs 1 and 2), including many images (click icons to reveal associated images). Hornak's book also provides a glossary of terms.

Gradient Coils: In the next section of Chapter 9, Gradient Coils, three paragraphs describe the gradient coils, which work together carrying opposing current to establish the magnetic field gradient.

RF Coils: The next section of Chapter 9, RF Coils, provides a description of RF coils, which are are responsible for the rotation of the magnetic field.

Assessment

Unit Summary

Grand Challenge Project: Give students the Grand Challenge Project Handout, which states the challenge and suggests three possible ways for them to "go public" by creating presentations relating back to the initial challenge problem on MRI safety: design an instructional safety pamphlet for hospital staff, design a website for hospital employees to get information, make a slide presentation for hospital trainers to use to inform hospital staff. Presentations must cover safety issues and the pertinent scientific concepts relating to magnetostatics and electromagnetism. Refer to the Go Public Grading Rubric for suggested grading criteria.

• Challenge: A nearby hospital has just installed a new magnetic resonance imaging facility that has the capacity to make three-dimensional images of brains and other body parts by putting patients into a strong magnetic field. The hospital wants its staff to have a clear understanding of the risks involved with working near a strong magnetic field and a basic understanding of why those risks occur. Your task is to develop a presentation or pamphlet explaining the risks involved, the physics behind those risks, and recommended safety precautions for all staff members to take.

Additional Multimedia Support

The FDA's eight-page A Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems, is available at http://www.cognitiveneuro.org/SafetyReadings/FDAExternalDeviceGuidance%201997.pdf.

Hornak, Joseph P. “Chapter 9: Imaging Hardware” in The Basics of MRI (a hypertext book). http://www.cis.rit.edu/htbooks/mri/ and http://www.cis.rit.edu/htbooks/mri/chap-9/chap-9.htm.

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under National Science Foundation RET grants no. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.