Magnetic Nanoparticle Imaging Using Harmonic Signals

Othman, Norzila; Tsubaki, T.; Yonetani, Takashi; Enpuku, Keiji; Kandori, Akihiko

doi:10.1109/tmag.2012.2198440

Cited by 22 publications

(12 citation statements)

References 9 publications

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“…For this purpose, we used the SVD technique, whose details are given elsewhere. 17,25) In performing the SVD technique, we took the number of singular values as 90. In obtaining the MNP distribution n, we used a threshold value for n j .…”

Section: Detection Of Multiple Mnp Samplesmentioning

confidence: 99%

“…For this purpose, several magnetic properties of MNPs have been used, such as ac susceptibility, 1,2) magnetic relaxation, [3][4][5][6] and nonlinear magnetization. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] Detection methods using nonlinear magnetization have been classified into three types, namely, harmonic-space MPI, [7][8][9][10][11][12] x-space MPI, [13][14][15] and narrowband MPI. [16][17][18][19][20] By analyzing the measured contour map, one can reconstruct an image of the spatial distribution of the MNPs.…”

Section: Introductionmentioning

confidence: 99%

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Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

Enpuku

Miyazaki

Morishita

et al. 2015

Jpn. J. Appl. Phys.

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Magnetic particle imaging (MPI) has been extensively studied for in-vivo biomedical diagnosis. We developed a narrowband MPI system utilizing third harmonic detection. The third harmonic signal from the magnetic nanoparticles (MNPs) was detected with a pickup coil cooled to 77 K, and its output was read out with a resonant circuit. The noise of the detection system was S 1=2 B ¼ 12 fT/Hz 1/2 at a signal frequency of 8.79 kHz. We also introduced the so-called gradient field with a field gradient of 0.3 T/m in order to improve the MPI spatial resolution. We first clarified the properties of MNPs, which provided the basis for MPI using the gradient field. Next, we measured the signal-field map generated from the MNPs when an excitation field with a root mean square value of 1.6 mT and frequency of 2.93 kHz was applied. Using a mathematical technique called singular value decomposition (SVD), we reconstructed an image of the MNP distribution from the measured map. We demonstrated the detection of MNP samples as small as 1 µg at a distance of 50 mm. The spatial resolution of the reconstructed MNP distribution was approximately 10 mm. These results will indicate the feasibility of the system for the application to breast cancer detection.

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Section: Detection Of Multiple Mnp Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

Enpuku

Miyazaki

Morishita

et al. 2015

Jpn. J. Appl. Phys.

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“…The demand for magnetic measurements of both pure and mixed materials has increased recently. Magnetic nanoparticles for biomedical applications such as immunoassays [2][3][4][5][6][7], magnetic particle imaging (MPI) [8][9][10][11], and magnetic contrast media for magnetic resonance imaging (MRI) are widely used. For practical use, not only the magnetic properties of the isolated material but also those of the material in a medium are important.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Type HTS-SQUID Magnetometer With Vibrating and Rotating Sample

Tsukada

Morita

Matsunaga

et al. 2016

IEEE Trans. Appl. Supercond.

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Highly sensitive measurement of the very weak magnetic characteristics of magnetic particles in solution or of a solution itself is required for applications such as biomedical examinations. In this study, higher sensitivity and additional performance with relaxation measurement and harmonic signal detection were achieved by improvement of the driving mechanism and high resolution electric magnet, and optimization of the superconducting quantum interference device (SQUID) detection unit. A servomotor was used for sample vibration and rotation with precise control and high speed. For detection of the M-H characteristics, the sample was vibrated under the magnetic field in the electromagnet. For measuring the relaxation of the magnetization, the sample was rotated. A first-order differential pickup coil with a normal conducting wire connected to the input coil of a high temperature superconductor (HTS)-SQUID was used to detect the magnetic signal from the sample. High resolution measurement of the magnetic moment in the order of 10 -11 A m 2 was achieved with this system configuration. An AC magnetic field with a DC bias could then be applied to the sample for detection of the harmonic signal. The magnetic relaxation signal from the sample was measured by another of the same type of differential detection coil equipped outside of the electric magnet by rotating instead of vibrating the sample. Magnetization curve for a lowconcentration of iron nanoparticles with superparamagnetic character in solution was successfully measured using the developed magnetometer, and the relaxation phenomenon was also characterized.  Index Terms-magnetic susceptibility, SQUID, magnetometer, magnetization, Brownian relaxation.

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“…Previous high-sensitivity imaging systems have been based on various detection methods employing AC susceptibility, magnetic relaxation, and harmonic signal detection from the nonlinearity of the magnetization (M-H) curve [1]- [6]. As MPI generally utilizes harmonic signals, it is important to select MNPs that can generate strong harmonic signals.…”

Section: Introductionmentioning

confidence: 99%

Harmonic Signal Analysis for Magnetic Nanoparticle Imaging

Othman

Tsubaki

Kitahara

et al. 2014

J. Jpn. Soc. Powder Powder Metallurgy

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A harmonic signal analysis of magnetic nanoparticles (MNPs) used as tracers in magnetic particle imaging (MPI) was conducted. The harmonic spectrum from three types of immobilized MNPs namely, Resovist, fluidMAG, and SupraBead, were measured at excitation fields of 1.4 mT and 28 mT with a frequency of 10 kHz. Resovist showed the richest spectrum, followed by fluidMAG and SupraBead.These different harmonic properties among samples were analyzed on the basis of the magnetic moment m and anisotropy energy E B of the MNPs. We show the conditions of m and E B required for harmonic signal generation. As m and E B are widely distributed within As MPI generally utilizes harmonic signals, it is important to select MNPs that can generate strong harmonic signals. However, MNPs show a wide variety of magnetic properties, depending on their magnetic moment m and anisotropy energy E B [7]. Therefore, it is important to establish a clear quantitative relationship between these parameters and harmonic signals in order to determine suitable MNPs for MPI applications.In this study, we investigate the properties of the harmonic signals generated by MNPs. First, we measure the harmonic signals from three types of commercial MNPs, namely, Resovist®, fluidMAG, and SupraBead. Then, samples with different harmonic properties are analyzed using the m and E B of MNPs. We also perform a numerical simulation for harmonic spectrum based on the Landau-Lifshitz-Gilbert (LLG) equation. A good agreement is obtained between the measured spectrum and the numerical simulation.

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Magnetic Nanoparticle Imaging Using Harmonic Signals

Cited by 22 publications

References 9 publications

Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

Hybrid Type HTS-SQUID Magnetometer With Vibrating and Rotating Sample

Harmonic Signal Analysis for Magnetic Nanoparticle Imaging

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