Performance Test of 1.5 T Cryogen-Free Orthopedic MRI Magnet

Bagdinov, A. V.; Демихов, Е. И.; Kostrov, E. A.; Лысенко, В. В.; Piskunov, Nikolay; Рыбаков, А. С.; Tysyachnykh, Yuri

doi:10.1109/tasc.2017.2784402

Cited by 12 publications

(5 citation statements)

References 11 publications

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“…Its high demand and the limited number of suppliers have led to increased and fluctuating prices, global shortages, 54 and uncertainty about its future availability 22 . Furthermore, the lack of liquid helium sources is a crucial cause of the reduced access to high‐field MRI in remote areas and developing countries 55,56 . The regular NbTi liquid helium‐bathed magnets operate at 4.2 K and contain approximately 1500–2000 L of liquid helium 57 .…”

Section: Accessible Magnet Configurationsmentioning

confidence: 99%

“…22 Furthermore, the lack of liquid helium sources is a crucial cause of the reduced access to high-field MRI in remote areas and developing countries. 55,56 The regular NbTi liquid helium-bathed magnets operate at 4.2 K and contain approximately 1500-2000 L of liquid helium. 57 Early systems required periodical cryogen refills, which progressively became more spaced as cryocooler innovations reduced their consumption per hour.…”

Section: Reduced Liquid Helium Mrimentioning

confidence: 99%

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Superconducting magnet designs and MRI accessibility: A review

2023

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Presently, magnetic resonance imaging (MRI) magnets must deliver excellent magnetic field (B0) uniformity to achieve optimum image quality. Long magnets can satisfy the homogeneity requirements but require considerable superconducting material. These designs result in large, heavy, and costly systems that aggravate as field strength increases. Furthermore, the tight temperature tolerance of niobium titanium magnets adds instability to the system and requires operation at liquid helium temperature. These issues are crucial factors in the disparity of MR density and field strength use across the globe. Low‐income settings show reduced access to MRI, especially to high field strengths. This article summarizes the proposed modifications to MRI superconducting magnet design and their impact on accessibility, including compact, reduced liquid helium, and specialty systems. Reducing the amount of superconductor inevitably entails shrinking the magnet size, resulting in higher field inhomogeneity. This work also reviews the state‐of‐the‐art imaging and reconstruction methods to overcome this issue. Finally, we summarize the current and future challenges and opportunities in the design of accessible MRI.

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Section: Accessible Magnet Configurationsmentioning

confidence: 99%

Section: Reduced Liquid Helium Mrimentioning

confidence: 99%

Superconducting magnet designs and MRI accessibility: A review

2023

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“…A cryogen-free solution reduces the cost of operation by removing the need for liquid helium, which has a limited supply and continuously rising price [9]. Removing the liquid helium cooling system significantly decreases the scanner bulk (volume and weight) and obviates the need for cryogen storage and quench ducting [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Design, construction and performance testing of a 1.5 T cryogen-free low-temperature superconductor whole-body MRI magnet

Wang

Wang²,

Liang³

et al. 2023

Supercond. Sci. Technol.

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This work describes the design, construction, and testing of a 1.5 T cryogen-free LTS NbTi whole-body magnet with a bore diameter of 850 mm that is suitable for clinical MRI applications. The magnet was actively shielded and passively shimmed to achieve the confinement within a 0.5 mT stray magnetic field at 2.5/4 m radial/axial positions and 12.1 ppm field inhomogeneity over the 45 mm DSV. The magnet was conductively refrigerated using a two-stage GM cryocooler and can be maintained at a steady temperature of below 5.7 K during MRI scanning. The MRI scanner assembled with the designed cryogen-free magnet demonstrated stable performance and provided MRI images with good quality and high contrast.

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“…However, the low minimum quench energy (MQE) of NbTi conductors makes the development and protection of these systems more demanding. This might require the operation of a 1.5 T conduction-cooled NbTi MRI coil with a small I op /I c [5]. In any case, care must be taken to significantly increase the thermal margin and strongly reduce the possibility of perturbations, mechanical and otherwise.…”

Section: Introductionmentioning

confidence: 99%

Quench, normal zone propagation velocity, and the development of an active protection scheme for a conduction cooled, react-and-wind, MgB₂ MRI coil segment

Zhang

Sumption

Majoroš

et al. 2019

Supercond. Sci. Technol.

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The development of coils that can survive a quench is crucial for demonstrating the viability of MgB2-based main magnet coils used in MRI systems. Here we have studied the performance and quench properties of a large (outer diameter: 901 mm; winding pack: 44 mm thick × 50.6 mm high) conduction-cooled, react-and-wind, MgB2 superconducting coil. Minimum quench energy (MQE) values were measured at several coil operating currents (Iop), and distinguished from the minimum energy needed to generate a normal zone (MGE). During these measurements, normal zone propagation velocities (NZPV) were also determined using multiple voltage taps placed around the heater zone. The conduction cooled coil obtained a critical current (Ic) of 186 A at 15 K. As the operating currents (Iop) varied from 80 to 175 A, MQE ranged from 152 to 10 J, and NZPV increased from 1.3 to 5.5 cm s−1. Two kinds of heater were involved in this study: (1) a localized heater (‘test heater’) used to initiate the quench, and (2) a larger ‘protection heater’ used to protect the coil by distributing the normal zone after a quench was detected. The protection heater was placed on the outside surface of the coil winding. The test heater was also placed on the outside surface of the coil at a small opening made in the protection heater. As part of this work, we also developed and tested an active protection scheme for the coil. Such active protection schemes are of great interest for MgB2-based MRIs because they permit exploitation of the relatively large MQE values of MgB2 to enable the use of higher Je values which in turn lead to competitive MgB2 MRI designs. Finally, the ability to use a quench detection voltage to fire a protection heater as part of an active protection scheme was also demonstrated.

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Performance Test of 1.5 T Cryogen-Free Orthopedic MRI Magnet

Cited by 12 publications

References 11 publications

Superconducting magnet designs and MRI accessibility: A review

Superconducting magnet designs and MRI accessibility: A review

Design, construction and performance testing of a 1.5 T cryogen-free low-temperature superconductor whole-body MRI magnet

Quench, normal zone propagation velocity, and the development of an active protection scheme for a conduction cooled, react-and-wind, MgB₂ MRI coil segment

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Performance Test of 1.5 T Cryogen-Free Orthopedic MRI Magnet

Cited by 12 publications

References 11 publications

Superconducting magnet designs and MRI accessibility: A review

Superconducting magnet designs and MRI accessibility: A review

Design, construction and performance testing of a 1.5 T cryogen-free low-temperature superconductor whole-body MRI magnet

Quench, normal zone propagation velocity, and the development of an active protection scheme for a conduction cooled, react-and-wind, MgB2 MRI coil segment

Contact Info

Product

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Quench, normal zone propagation velocity, and the development of an active protection scheme for a conduction cooled, react-and-wind, MgB₂ MRI coil segment