Heat generation ability in AC magnetic field of needle‐type Ti‐coated mild steel for ablation cancer therapy

Abstract

PurposeThe purpose of this paper is to develop a ferromagnetic needle adaptable for a novel ablation cancer therapy; the heat generation ability of the mild steel rod embedded into the Ti‐tube having a different thickness was investigated in a high‐frequency output at 300 kHz.Design/methodology/approachThe outer diameter and length of the Ti‐tubes were 1.8 and 20 mm, respectively, while the inner diameter was varied from 1.6 to 0 mm. The mild steel rod was embedded in a Ti‐tube for preparing the needle‐type specimen. Their heat generation ability was examined by changing the inclination angle to the magnetic flux direction in a high‐frequency coil.FindingsWhen the thickness of the Ti surrounding the mild steel rod was as low as 0.1 mm, the heat generation ability was drastically different among the three inclination angles (θ=0°, 45°, and 90°) to the magnetic flux direction due to the effect of the shape‐induced magnetic anisotropy. However, the effect of the inclination angle was almost eliminated in the specimen surrounded by the 0.4 mm thick Ti, suggesting that the non‐oriented heat generation property is achieved for the needle‐type mild steel rod coated with Ti having the optimum thickness.Originality/valueThe prototype ablation needle having a complete non‐oriented heat generation ability was fabricated to use in subsequent animal experiments. It is considered that the newly designed Ti‐coated device is useful in ablation treatments using a high‐frequency induction heating.