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

Abstract

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 (u ¼ 08, 458, and 908) 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.

Heat Generation and Transfer Behaviors of Ti-Coated Carbon Steel Rod Adaptable for Ablation Therapy of Oral Cancer

“…In a previous paper [ 20 ], we reported the heating properties of a carbon steel rod embedded into Ti-tubes of various inner diameters in a high-frequency induction field at 300 kHz. Based on the previous experiments, there was an optimum thickness to minimize the effect of the inclination angle relative to the magnetic flux direction.…”

Consideration of different heating lengths of needles with induction heating and resistance system: A novel design of needle module for thermal ablation

“…Based on this method, coils surround the needles and area of the patient. Therefore, the inclination angle between the needle and magnetic flux direction generated by the induction coil will also be varied, and this affects the heat generation ability in the needle [Naohara et al, 2011]. And, in order to generate heat energy most effectively, all needles used in AEF have been made from or coated with ferromagnetic materials, such as ferrite (Fe 3 O 4 ) or magnesium ferrite (MgFe 2 O 4 ) [Stauffer et al, 1984b;Muraoka et al, 2004;Hirakawa et al, 2008;Sato et al, 2008].…”

“…Eddy current losses occur in any electrically conducting material with both ferromagnetic material and nonmagnetic material in an AEF [Stauffer et al, 1984a; Grant sponsor: National Natural Science Foundation; grant numbers: 31470824, 31000382. Muraoka et al, 2004;Gellmand et al, 2005;Sato et al, 2008;Watanabe et al, 2009;Chen et al, 2010;Naohara et al, 2011;Zuchini et al, 2011;Wang et al, 2013;Huang et al, 2012Huang et al, , 2014.…”

“…In addition, the orientation of a needle may widely vary because of the locations of the tumors. Therefore, the inclination angle between the needle and magnetic flux direction generated by the induction coil will also be varied, and this affects the heat generation ability in the needle [Naohara et al, 2011]. Moreover, with external induction heating, heating only a segment of the needle which is embedded in the tumor is difficult or requires a complicated design using the conducting material for the heated-needle segment and nonconducting material, such as ceramic, for the other segments [Zuchini et al, 2011;Huang et al, 2014].…”

Heat generation properties in AC magnetic field for composite powder material of the Y3Fe5O12–nSiC system prepared by reverse coprecipitation method

“…Materials of the needle type and powder type have been studied for this purpose. For the needle type metal materials, they are directly inserted from the surface into the tissues as in the case of cervical cancer and heated by an eddy loss in an AC magnetic field [8][9][10].…”