Electromagnetic fields in MRI Machines

What Is An MRI Machine?

What Is It?

• A Magnetic Resonance Imaging machine, commonly known as an MRI is used as a non-invasive medical imaging device to produce three dimensional images.

• MRI's are used to detect and diagnose diseases. Some diseases that can be detected are brain tumors, traumatic brain injuries, multiple sclerosis and dementia.

• MRI machines use a strong magnetic field and a radio-frequency pulse to produce 3-D images of specific soft tissues in the human body.

How Does An MRI Machine Work?

How It

Works

• The patient lies on a movable bed that slides into a tube in the center of the magnetic field. (408)

• A superconducting magnet is used to create a strong magnetic field, and three smaller gradient magnets are used to alter the magnetic field to focus on specific areas of soft tissue. Hydrogen atoms within the body align their poles in the same direction or opposite to the magnetic field.

• A radio frequency pulse is directed towards the part of the body that needs to be examined. The pulse causes the anti-aligned atoms to spin and align with the magnetic field.

• Once the pulse ends, those atoms spin around again, but will emit energy that they absorbed from the pulse. As the MRI is sending these radio pulses there are three gradient magnets that are activated, quickly turning on and off in a pattern.

• Alteration of these gradient magnets allows the MRI to focus on one part of the body. The MRI will send a signal to a computer, which converts the information into an image.

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The History Of MRI Machines

History

1945 - NMR was initially demonstrated.

1969 - Dr. Raymond Damadian hypothesized that cancer cells hold more water and would show up in MR due to the increased number of hydrogen atoms.

1971 - Damadian performed an experiment on cancerous and healthy rats, and published his research.

1971 - Paul Lauterbur performed a similar experiment on dead tissue, then came up with a way to image living tissue. He published his theory and imaged two water-filled test tubes (first MR image).

1972 - Sir Peter Mansfield theorized that adding a magnetic field gradient could allow scientists to look at the atomic structure of a chemical and create 3-D images.

May 1977 - Damadian created the first whole-body MRI machine.

1984 - Approved for use by the FDA.

https://www.gehealthcare.com/feature-article/when-and-why-was-mri-invented

Future Advancements Of The MRI Machine

Future

Advancements

The following research has been done by NIBIB (National Institute of Biomedical imaging and Bioengineering) researchers:

• A method has been developed to turn sound waves into images of the liver. This is a non- invasive, painless approach to find tumors or tissue damaged by liver disease. The MRE device (a pad placed against your body) is placed on the liver of the patient before going into the MRI. this pulses waves through the liver and allows the MRI to detect the density and health of the liver.

• Researchers are attempting to build a pediatric body MRI, creating a pediatric coil made for smaller bodies. The image can be done more quickly, clearer, and in less time. this will make the MRI safer, and more available to children.

• Researchers have discovered a way to inject specialized compounds into patients with prostate cancer. This measures the metabolic rate of a tumor. this information can provide a fast and very accurate picture of the tumors aggressiveness.

What Careers Are Linked To Electromagnetic Fields & MRI Machines?

Career Links

• Radiologist technician & MRI technician- These technicians assist doctors by helping to prep the patient before entering the MRI machine. They operate the MRI & help produce a quality image.

• Radiologist- A specialized doctor that uses images produced by the MRI machine to diagnose a disease. Radiologists write reports based on the images and send them to a patients family/ designated doctor.

• Biomedical Engineer- An engineer that designs, develops and evaluates anything medical related. They handle things like artificial organs, prosthetic implants & medical instruments such as the MRI.

• Radiologist/MRI Tech Salary: $80,000
• Radiologist Salary: $325,000
• Biomedical Engineer Salary: $108,000

Benefits of MRI Machines

Benefits to

Society

• MRI's do not involve radiation and are non-invasive.

• MRI's do not use any iodine-based substances and are therefore less likely to result in an allergic reaction.

• MRI's produce very clear and detailed images, allowing abnormalities to be easily visible.

• MRI machines can create hundred of images from all angles and orientations.

• MRI machines help diagnose cancer.

• MRI machines improved the way people viewed hospitals.

Relating to the Course

Relating to

the Course

• Magnetic fields interact with the hydrogen ions in the water in our bodies

• The magnetic fields are created based on the hydrogen ions north and south poles.

• A magnetic field is created using superconducting coils in the MRI machine

more information can be found on page 408 in the textbook.

Want To Hear Some Cool Facts???

Fun Facts

• The Earth's magnetic field is about 0.5 gauss, and a typical MRI machine produces a magnetic field that is between 5,000 and 20,000 gauss.
• The magnets found in an MRI machine must be cooled to absolute zero (or as close as you can get to that), which is usually done with liquid hydrogen.
• MRI scans typically take between 10 minutes and 2 hours.
• MRI's do not use ionizing radiation, unlike x-rays and CT scans.
• During the scan, the doctor may have the patient wear headphones or earplugs to block out the banging noises made by the scanner. They may also have the patient hold their breath at certain points.