Liquid helium, the lifeblood of MRI machines

publication date: Apr 15, 2019

The first MRI scan of a human took place in 1977 and this method of imaging diagnostics has developed so rapidly that it is now found in almost every major hospital in developed economies.

Liquid helium plays an essential role in the technology to cool the superconducting magnets that generate high resolution images of the human body.

Afrox’s Technical Services Manager for Special Products and Chemicals Hans Strydom talks to gasworld about helium’s role in enabling these life-changing machines to work effectively and reliably.

“To successfully diagnose conditions such as strokes, tumours, aneurysms, spinal cord injuries, multiple sclerosis, and eye or inner ear problems, the medical community needs imaging technologies that provide high-contrast, detail-rich views of the inner workings of the human body,” he explains.

“MRI is a game-changing imaging technique that gives unprecedented levels of clarity, especially when scanning soft tissue such as the brain or muscles. It also helps doctors to see inside joints, cartilage, ligaments, muscles and tendons, which makes it helpful for detecting various sports injuries.”

“And, unlike traditional X-rays, MRIs do not expose the patient to radiation.”

MRI Machine

MRI works because of the large amounts of water present in the human body. Water molecules contain hydrogen atoms, each with a single proton that is spinning. The spinning axes of these protons are aligned in the presence of the very strong magnetic field applied by the MRI scanner.

A pulse of electromagnetic energy from the MRI pushes the ‘spin’ on these protons off the aligned path. When the pulse is turned off, the protons begin to move back into alignment, releasing the electromagnetic energy they gained. This energy is measured by the scanner and used to create the MRI image.

“To work, MRIs require a coolant to give the magnetic coils in the scanner superconductive properties. This enables an electrical current to flow through the coils with little resistance, enabling the high intensity magnetic fields to be generated,” Strydom explains.

“Liquid helium is the only medium cold enough to deliver the superconductivity levels required in MRI scanners in metals.”

“Another challenge for the imaging business is uptime. Given the high up-front investment and operational costs of MRI equipment, hospitals are keen for these expensive assets to be continuously scanning patients so that the expense can be fully justified.”

“This means that maintenance tasks such as recharging the units with liquid helium need to be completed as rapidly as possible so that units can be returned to service within short scheduled maintenance windows.”

“With the most diversified helium sourcing portfolio in the industry, Afrox is uniquely positioned to meet these needs for reliability and speed. In addition, hospitals have the reassurance of our global delivery capabilities.”

“Our L5 filling capabilities on the liquid helium offering is bundled with an extensive service package designed to maximise uptime and efficiency gains. Extending across the entire logistics chain from ordering through delivery to the point of use, our service experts save MRI operators time and money by ensuring the highest fill efficiency levels in the industry.”

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