A Flexible Spiral Antenna for Medical Application

Abstract

A newly developed flexible spiral applicator, which realize wide band operation, is presented to achieve microwave heating for hyperthermia. The heating pattern of the applicator can be controlled by changing the applied frequency. The experimental results and the simulated ones using phantom modeling materials show that the applicator can be used to heat relatively wide portion effectively. I. INTRODUCTION One of the most popular and effective form for hyperthermia treatment of cancer is a combination of radiotherapy and hyperthermia for tumors located near the body surface. This is because heating and temperature measurement are relatively simple, and the evaluation of the effectiveness of therapy is more accurate. In order to heat near the body surface, using microwaves are one of the best ways[l]. In this heating modality called as microwave hyperthermia, many heating applicators are developed against various superficial heating targets of the human bodYP1. Most applicators for microwave hyperthermia treatment of cancer operate in a narrow fkquency band. Some applicators can change their heating patterns, to realize an optimum heating against various tumors inside the human body[3]-[5]. Nevertheless, it is generally difficult for a single applicator to control the heating pattern at a single frequency. In this paper, a flexible spiral antenna for hyperthermia heating is proposed and tested. The flexibility of the applicator makes it possible to contact directly to the heating target whose surface is sometimes uneven. The applicator can operate in a large frequency band. If the frequency is opMdly chosen against the certain tumor sites and sizes, it may be possible to heat the tumor effectively.