@misc{oai:repo.qst.go.jp:00079551,
 author = {Kuwahata, Akihiro and Kitaizumi, Takahiro and Saichi, Kota and Sato, Takumi and Igarashi, Ryuji and Ohshima, Takeshi and Masuyama, Yuta and Iwasaki, Takayuki and Hatano, Mutsuko and Jelezko, Fedor and Kusakabe, Moriaki and Yatsui, Takashi and Sekino, Masaki and Igarashi, Ryuji and Ohshima, Takeshi and Masuyama, Yuta and Hatano, Mutsuko},
 month = {Dec},
 note = {Introduction
Quantum sensing, utilizing the negatively charged nitrogen-vacancy (NV–) color center in a diamond, has potentially yielded highly sensitive magnetic sensing [1]. In our previous study, the developed magnetometer using the NV centers in the bulk diamond (100) has demonstrated the detection of magnetic nanoparticles (MNPs) phantoms; the minimum detection amount of few micrograms of the MNPs at the few mm distance [2]. In this paper, we report the detection of the MNPs in the lymph node of the rat animal as one of the biomedical applications.

Method
The MNPs were injected into the rear footpad and accumulated into the lymph nodes via the lymphatics system. The node was excised one day after the injection, and the detection of MNPs accumulated in the node was performed at the front of the magnetometer head.

Results & Discussion
  The magnetometer composes of an excitation coil, a cancel coil, and a permanent magnet (Fig. 1(a)); the excitation coil generates the magnetic fields to magnetize the MNPs, the cancel coil removed the magnetic field at the NV centers to reduce noise signals, the magnet produces the eight dip in optically detected magnetic resonance (ODMR). The detection of magnetic fields originated from the MNPs is based on the lock-in detection. Figure 1(b) shows the lock-in signal in the ODMR spectrum. The lock-in signal originated from the magnetized MNPs increased with increasing the microwave (MW) power as shown in Fig. 1(c). We succeeded to detect the MNPs containing in the rat lymph node. We will present the detailed, such as the amount of MNPs in the lymph nodes, the numerical evaluation to validate the experimental results, and the detection distance., The 2nd International Forum on Quantum Metrology and Sensing への出席},
 title = {Diamond NV Magnetometer for Detecting Magnetic Nanoparticles in Rat Lymph Nodes},
 year = {2019}
}