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

Purpose – The 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/approach – The 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. Findings – When 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/value – The 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. [ABSTRACT FROM AUTHOR]