Hyperthermia Implant Consisting of Resonant Circuit Delivered to Tumor Through 18 G Needle

A resonant circuit is expected to be used as a heating source for hyperthermia implants, because the circuit can be effectively heated by an applied ac magnetic field. In order to realize a less invasive delivery of the implant through a catheter or injection needle, its miniaturization down to 1 mm or less is essential. However, the heating temperature of the resonant circuit is reduced by downsizing of the size of the circuit. A ferrite core in a coil is employed in order to obtain higher induced voltage in the inductor, resulting in the higher temperature rise of the resonant circuit. The resonant circuit implant consisting of the core coil has been prepared. Its diameter is 0.9 mm and the implant can be delivered through an 18 G needle.