Superconductivity in Magnetic Resonance Imaging machines

| James Detlefs

Summary: superconductivity is critical in MRI machines because superconducting-wire magnets can create more powerful magnetic fields than ordinary wires. The higher the strength of the magnetic field an MRI machine can generate, the higher the MRI image resolution. 

Magnetic resonance imaging (MRI) machines produce detailed images of the inside of the human body. A combination of high magnetic fields and RF signals creates high-resolution images utilizing the spin of hydrogen atoms found in water molecules in bodily tissues. 

A patient lies on a movable bed and is inserted into a giant cylindrical magnet. The magnet creates a strong, uniform magnetic field around the patient’s body. In MRI, this magnet must be extremely powerful, typically on the order of 1.5 to 3 tesla, to produce the high-resolution images needed for diagnosis. MRI machines use wire made of unique superconducting materials which achieve zero electrical resistance when cooled to extremely low temperatures to create a more powerful magnet.

The superconducting wire is cooled using liquid helium, reaching temperatures around -269°C (-452°F). When the wire reaches this temperature, it undergoes a quantum phase transition into the superconducting state. As a superconductor, it can carry large amounts of electrical current with 100% efficiency. This excellent efficiency allows the MRI machine to generate a powerful magnetic field. 

Magnetic fields in an MRI machine are crucial because they help align the nuclear spins of the hydrogen atoms in the patient’s body. Hydrogen atoms are the most abundant in the human body and are present in the water molecules in bodily tissues.

During an MRI scan, radio waves are transmitted into the patient’s body, causing the hydrogen nuclei to become momentarily displaced from their equilibrium positions. When the radio waves are off, the hydrogen nuclei return to their equilibrium positions and emit a small amount of energy in the form of a radio frequency (RF) signal. The RF signals detected by the MRI machine create an image of the inside of the body. Different tissues in the body emit different levels of RF signal, and this information is vital to develop a contrast-enhanced image that shows the various tissues in the body. 

The amount of superconducting wire used in an MRI machine depends on the size and strength of the magnet. In general, MRI magnets have categorizations as low field (0.2-0.7 tesla), medium field (0.7-1.5 tesla), or high field (1.5-3 tesla). The magnet’s strength determines the resolution of the images produced by the MRI machine, with stronger magnets producing higher-resolution images.

For example, a high-field MRI magnet might use several kilometers of superconducting wire to create a magnetic field of around 3 teslas. This wire would be wound into coils to create the desired field strength and shape. The exact amount of wire used would depend on the specific design of the magnet and the desired field strength.

In contrast, a low-field MRI magnet might only use a few hundred meters of superconducting wire to create a magnetic field of around 0.5 teslas. Again, the exact amount of wire used would depend on the specific design of the magnet and the desired field strength.

Overall, the amount of superconducting wire used in an MRI machine can vary widely depending on the size and strength of the magnet.

Several companies produce superconducting wire for various applications, including MRI machines, particle accelerators, and other scientific and medical equipment. Companies in the market for superconducting wire include:

  • American Superconductor Corporation (AMSC)
  • SuperPower, Inc.
  • Hyper Tech Research, Inc.
  • HTS Texas, Inc.
  • Supercon, Inc.
  • Schott North America, Inc.
  • Bruker BioSpin Corporation
  • Cryomagnetics, Inc.
  • National High Magnetic Field Laboratory (NHMFL)

These companies produce a range of superconducting wires and materials, including high-temperature superconductors (HTS) and low-temperature superconductors (LTS). They also offer a variety of sizes and shapes of wire to meet the specific needs of different applications. It is difficult to determine which company is the largest producer of superconducting wire. The market is constantly evolving, and many sources of information on global production figures exist.

American Levitation

| James Detlefs

“Elevating the future with superconducting technology”

Superconductivity is a fascinating phenomenon that has the potential to revolutionize a variety of industries. In simple terms, superconductivity is a state in which a material can conduct electricity with zero resistance. This means that a current can flow through a superconducting material indefinitely without losing energy to resistance, leading to a number of potentially game-changing applications.

One of the most well-known applications of superconductivity is in the field of electromagnetism. Superconducting materials can be used to create extremely strong and stable magnetic fields, which has a number of important implications. For example, MRI machines rely on superconducting materials to generate the powerful magnetic fields needed to produce detailed images of the human body. Similarly, superconducting magnets are used in particle accelerators, which are used to study the fundamental building blocks of matter.

Another potential application of superconductivity is in the field of energy. Because superconducting materials can conduct electricity with zero resistance, they could be used to create highly efficient power transmission lines. This would allow electricity to be transmitted over long distances with minimal loss, potentially leading to more efficient and sustainable energy systems.

There are also a number of other potential applications of superconductivity, including in the fields of transportation and computing. For example, researchers are exploring the use of superconducting materials in the development of high-speed trains that could potentially levitate above the tracks. In computing, superconducting materials could be used to create ultra-fast, low-power computer chips.

Overall, the potential applications of superconductivity are vast and varied, and researchers are constantly exploring new ways to harness this phenomenon. As our understanding of superconductivity continues to grow, it’s likely that we will see even more innovative and game-changing applications in the future.