Design of an axisymmetric permanent magnet structure for magnetic resonance tomography

Molfino, P.; Repetto, Maurizio; Bixio, A.; Mut, G. Dal; Marabotto, R.

doi:10.1109/20.11395

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…Passive pole pieces design which consists of several convex or concave annuluses on the pole is widely used in products to improve the field uniformity [4,5]. Since the convex or concave degree is nonlinear with the field, some intelligent optimization methods are used with 2D FEM to optimize the shape of the pole pieces.…”

Section: Insufficiencies In Filter Equationmentioning

confidence: 99%

Optimization Method for Passive Pole Pieces Design

Wang¹,

Zhu²,

Song³

et al. 2007

PIERS Online

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The pole pieces of permanent magnet require precise design since the highly uniform magnetic field are needed for nuclear magnetic resonance imaging. A new method has been introduced in this paper to optimize the shape of passive pole pieces. Based on Filter Equation [1, 3] a field alteration function is proposed in this method to indicate the magnetic field change according to the pole pieces variation. And this function is optimized with BFGS method to determine the shape of pole pieces which produce the most uniform magnetic field. Simulation indicates that this method is much better than the optimization methods in previous published papers with respect to the speed and field uniformity.

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Section: Insufficiencies In Filter Equationmentioning

confidence: 99%

Optimization Method for Passive Pole Pieces Design

Wang¹,

Zhu²,

Song³

et al. 2007

PIERS Online

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show abstract

“…The variational equation including the equality constraints (2) is multiplied by the Lagrange multiplier vector instead of and is added to the objective function (1). Then the augmented objective function is established as (4) where the subscripts, 1 and 2, mean the corresponding regions and , respectively.…”

Section: Derivation Of Continuum Sensitivity Formulamentioning

confidence: 99%

“…The variational equation of the adjoint system corresponding to the primary system can be easily found from the resultant equation (4). This variational equation is equivalent to the following differential equation in (5) where represents the applied loads in the adjoint system related to the objective function (1).…”

Section: Derivation Of Continuum Sensitivity Formulamentioning

confidence: 99%

“…The stochastic optimization or the design of experiment where magnetic fields were calculated by finite element method or the magnetic circuit method in simplified 2-D model was usually employed as a design tool [1]- [4]. However, for the actual 3-D magnet model, these existing methods could not guarantee optimal homogeneity condition of the magnetic field and working space volume constraint.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

3-D optimal shape design of ferromagnetic pole in MRI magnet of open permanent-magnet type

Kim¹,

Kim²,

Lee³

et al. 2002

IEEE Trans. Appl. Supercond.

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This paper presents 3-D optimal shape design method of ferromagnetic pole pieces for magnetic resonance imaging (MRI) devices of open permanent magnet type. The design method is based on a continuum sensitivity analysis in conjunction with the boundary integral equation method (BIEM). The magnetic poles of an open magnet assembly are designed by the proposed method and the conventional shimming method. Magnetic field strength, ppm order homogeneity and working space volume are compared between the proposed method and conventional one.Index Terms-Homogeneous magnetic field, magnetic resonance imaging (MRI) devices, open permanent magnet type, optimal shape design.

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Hard Magnetic Materials

Jiles¹

1991

Introduction to Magnetism and Magnetic Materials

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Design of an axisymmetric permanent magnet structure for magnetic resonance tomography

Cited by 5 publications

References 2 publications

Optimization Method for Passive Pole Pieces Design

Optimization Method for Passive Pole Pieces Design

3-D optimal shape design of ferromagnetic pole in MRI magnet of open permanent-magnet type

Hard Magnetic Materials

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