Development of inductive heating equipment using an inductive aperture-type applicator.

We designed an inductive aperture-type applicator, IATA, consisting of a one-turn, square, column-like coil made of a metal strip. In experiments using a phantom, this applicator was seen to have the following characteristics: (1) it does not excessively heat the fat layer; (2) deep portions can be heated effectively; (3) heat can be applied to the subject, without contact with the applicator; (4) excessive generation of heat does not occur in parts of tissue near the edge of the aperture; (5) size of the aperture can be changed for adaptation to size of the site to be heated; (6) the aperture can be modified to fit the shape of the subject and the depth of penetration is influenced by size of the subject being heated; (7) the applicator can be driven at an arbitrary frequency; (8) efficiency of heat generation to the input power is low. The inductive heating equipment, 'Inductron', which we have developed possesses the necessary requirements for adequate clinical application.