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<p>This paper critically examines a review of helium-free magnetic resonance imaging (MRI) systems. MRI systems historically have used superconducting magnets that operate in a passive liquid-helium bath for stability. The global helium shortage and complex safety system issues have accelerated conduction-cooled designs. This review examines the transition from passive cryogenic stabilization to active thermal and mechanical control and critically examines its effects. Closed-cycle refrigerators (PT and GM cycles) include fundamental thermodynamic principles, including cooling power at 4.2&#xa0;K and second-law relative efficiency to the Carnot limit. This review addresses the formal physical treatment of helium-free design constraints, including the severe reduction in specific heat capacity, narrower enthalpy margins, lower Minimum Quench Energy (MQE), and higher Normal Zone Propagation Velocity (NZPV). Recent studies indicate that helium-free MRI systems can provide diagnostically acceptable image quality for several routine musculoskeletal, neurological, and abdominal imaging applications under low- and mid-field operating conditions, but obstacles remain, such as limitations in image resolution, cryocooler-induced mechanical vibrations on Larmor frequency phase stability, and thermodynamic scaling constraints governed by Lorentz forces.</p>

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A Review on Helium-Free Magnetic Resonance Imaging Systems: Engineering Design, Clinical Performance, and Sustainability Considerations

  • 期刊论文

  • 发表日期：

    2026年6月15日

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  • M. Nisha Angeline,
  • S. K. Manikandan,
  • K. Vanchinathan,
  • Johny Renoald Albert,
  • K. P. Amalnath

摘要

This paper critically examines a review of helium-free magnetic resonance imaging (MRI) systems. MRI systems historically have used superconducting magnets that operate in a passive liquid-helium bath for stability. The global helium shortage and complex safety system issues have accelerated conduction-cooled designs. This review examines the transition from passive cryogenic stabilization to active thermal and mechanical control and critically examines its effects. Closed-cycle refrigerators (PT and GM cycles) include fundamental thermodynamic principles, including cooling power at 4.2 K and second-law relative efficiency to the Carnot limit. This review addresses the formal physical treatment of helium-free design constraints, including the severe reduction in specific heat capacity, narrower enthalpy margins, lower Minimum Quench Energy (MQE), and higher Normal Zone Propagation Velocity (NZPV). Recent studies indicate that helium-free MRI systems can provide diagnostically acceptable image quality for several routine musculoskeletal, neurological, and abdominal imaging applications under low- and mid-field operating conditions, but obstacles remain, such as limitations in image resolution, cryocooler-induced mechanical vibrations on Larmor frequency phase stability, and thermodynamic scaling constraints governed by Lorentz forces.