Development of a second-generation radiofrequency ablation using sintered MgFe₂O₄ needles and alternating magnetic field for human cancer therapy

Issue title: Selected papers presented at the International Symposium on Nanotoxicity Assessment and Biomedical Environmental Application of Fine Particles and Nanotubes, Hokkaido, Japan, 16–17 June 2008, Part 2

Article type: Research Article

Authors: Watanabe, Yuji^; | Sato, Koichi | Yukumi, Shungo | Yoshida, Motohira | Yamamoto, Yuji | Doi, Takashi | Sugishita, Hiroki | Naohara, Takashi | Maehara, Tsunehiro | Aono, Hiromichi | Kawachi, Kanji

Affiliations: Department of Surgery, Ehime University Graduate School of Medicine, Toon-shi, Japan | Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, Matsuyama, Japan | Department of Physics, Faculty of Science, Ehime University, Matsuyama, Japan

Note: [] Address for correspondence: Yuji Watanabe, MD, Department of Surgery, Ehime University Graduate School of Medicine, Toon-shi, 791-0295, Japan. Tel.: +81 89 960 5331; Fax: +81 89 960 5335; E-mail: [email protected].

Abstract: Magnetic metal particles are known to induce heat energy under an alternating magnetic field (AMF). We developed a local tumor-heating device incorporating an MgFe2O4 needle for the purpose of mild ablation for cancer treatment. A needle made from sintered MgFe2O4 particles was embedded in the hepatic or breast tumors. Tumors were then heated by the energy dissipated from the needle exposed to an AMF. We sequentially evaluated histological changes, cellular activity of tumors, and the extent of thermal effect using nicotinamide adenine dinucleotide (NADH) diaphorase and terminal deoxynucleotidyl tranferase-mediated digoxigenin-DUTP nick-end labeling (TUNEL) staining. The mean temperature of the tumor tissue during heating was about 60°C. Nuclei of the tumor cells became hyper-chromatin immediately after heating. The injured area spread progressively until 3 days after heating; when the area was surrounded by fibroblasts (meaning is not clear). Tumors disappeared after treatment without complications. This is the first time that the complete death of tumor cells has been realized by raising the tumor temperature above 60°C using the heat generated by magnetic metal particles exposed to AMF. This device may be useful in the future for local hyperthemic treatment of human cancers.

Keywords: Inductive heating, magnesium ferrite, cancer treatment, ablation

DOI: 10.3233/BME-2009-0569

Journal: Bio-Medical Materials and Engineering, vol. 19, no. 2-3, pp. 101-110, 2009