Narrowband magnetic nanoparticle imaging using cooled pickup coil and gradient field

Keiji Enpuku, Takashi Miyazaki, Manabu Morishita, Yuya Tsujita, Masaaki Matsuo, Shi Bai, Teruyoshi Sasayama, Takashi Yoshida

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


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 77K, and its output was read out with a resonant circuit. The noise of the detection system was SB1/2 = 12fT/Hz1/2 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 1μg at a distance of 50mm. The spatial resolution of the reconstructed MNP distribution was approximately 10mm. These results will indicate the feasibility of the system for the application to breast cancer detection.

Original languageEnglish
Article number057002
JournalJapanese journal of applied physics
Issue number5
Publication statusPublished - 2015

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)


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