Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

• Published in: Journal of magnetism and magnetic materials Vol. 427; pp. 144 - 150
• Main Authors: Sasayama, Teruyoshi, Tsujita, Yuya, Morishita, Manabu, Muta, Masahiro, Yoshida, Takashi, Enpuku, Keiji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2017; Elsevier BV
• Subjects: Coiling; Coils; Field strength; Gradient field; Least squares method; Magnetic particle imaging; Magnetism; Multiple pickup coils; Nanoparticles; Nonnegative least squares method; Pickup coils; Signal detection; Three dimensional imaging; Multiple pickup coils; Magnetic particle imaging; Gradient field; Nonnegative least squares method; Three-dimensional imaging
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2016.10.107

We propose a magnetic particle imaging (MPI) method based on third harmonic signal detection using a small field gradient and multiple pickup coils. First, we developed a system using two pickup coils and performed three-dimensional detection of two magnetic nanoparticle (MNP) samples, which were spaced 15mm apart. In the experiments, an excitation field strength of 1.6 mT was used at an operating frequency of 3kHz. A DC gradient field with a typical value of 0.2T/m was also used to produce the so-called field-free line. A third harmonic signal generated by the MNP samples was detected using the two pickup coils, and the samples were then mechanically scanned to obtain field maps. The field maps were subsequently analyzed using the nonnegative least squares method to obtain three-dimensional position information for the MNP samples. The results show that the positions of the two MNP samples were estimated with good accuracy, despite the small field gradient used. Further improvement in MPI performance will be achieved by increasing the number of pickup coils used. •3D magnetic particle imaging system combining field-free line and two pickup coils.•Imaging method based on third harmonic signal detection and small field gradient.•Nonnegative least squares method for 3D magnetic nanoparticle image reconstruction.•High spatial resolution despite use of small field gradient.