Fumiaki Okada

Dielectric-loaded lens applicator for microwave hyperthermia

The authors describe a lens applicator which can concentrate the E-plane field in a lossy medium and is constructed of an easily fabricated, dielectric-filled waveguide. Since the microwave field distribution on the aperture can be varied by using different sizes of dielectric material, the heating pattern inside the medium can be changed, allowing the configuration of a compact applicator that can heat portions deeper within the human body. Heating experiments on a model simulating human muscle have shown that an applicator with an aperture of 150*100 mm/sup 2/ achieves a maximum heating depth of over 80 mm, results that are compatible with the deep, localized heating required by hyperthermia. >

Flexible microstrip patch applicator for hyperthermia

A small, light, and flexible microstrip patch applicator is described. The dielectric part of the applicator consists of silicone rubber and water. Circulation of cooling water in the dielectric part is designed to cool the surface of the human body. The applicator with a total size of 150 mm*120 mm*7 mm operates at 430 MHz. The electric field distribution in the model indicates that effective heating at a depth of 50 mm in an area with a 65 mm diameter can be obtained using this technique.<<ETX>>

Study of dry phantoms for SAR simulation

In order to develop an applicator for microwave hyperthermia, it is necessary to use phantom models to simulate human tissues. In this paper, dry state phantom models which are very stable and easy to handle are studied. The phantom models are made of solid materials and soft materials, which are electrically simulated human muscle and fat. The models are very useful to simulate distribution of specific absorption rate (SAR) inside human tissue model.

Coupled microstrip applicator for hyperthermia application

A novel type of applicator with a coupled microstrip antenna for hyperthermia has been developed. The coupled microstrip antenna is designed to estimate the temperature change inside the human body by measuring the scattering parameter. Experimental results obtained using a simulated human model of 0.4% NaCl solution show that the transmission coefficient of the electric field changes by 0.73 dB/ degrees C in the range from 35 to 50 degrees C.<<ETX>>

Dielectric Loaded Microwave Lens Applicator for Effective Hyperthermia Treatment

A direct-contact high efficient lens applicator for local microwave hyperthermia treatment of cancer is proposed and developed. The applicator can heat deep and local portion in the dissipative medium such as human body. The dielectric loaded applicators operated at 2450 MHz and 430 MHz show that the heating depth can be reached above twice compared to the simple waveguide applicator which is usually used for hyperthermia. In designing low loss lens applicator, titanium oxide is loaded. The efficiency of the titanium oxide loaded lens applicator operated at 2450 MHz increased over 50 percent compared to that of the conventional lens applicator.