Real-Time 2D Microwave Differential Imaging for Temperature Monitoring

A non-invasive 2D microwave differential imaging (MDI) system for real-time temperature change monitoring is presented. The proposed MDI system operating at 925 MHz consists of a 16 channel array antenna, a cylindrical shaped imaging tank, a microwave switching matrix and a vector network analyzer. The MDI method for temperature monitoring is predicated on the changes in dielectric contrast of imaging targets with changing temperature. For reconstructed image, we use the Distorted Born Approximation (DBA) and Tikhonov regularization to solve 2D surface integral equation (SIE) and discrete linear inverse problem. The MDI system is tested on water target and a honeycomb shape phantom. Experimental results are presented to show the feasibility of the temperature monitoring inside human body for biomedical applications.

1. Introduction

Thermotherapy is a medical treatment technique based on the lesion in body exposure to high thermal dose. The high thermal dose are used to cause the lesion tissue destruction as a tumor ablation [1, 2]. The mild level of thermal dose provides physiological effect as pain relief in musculoskeletal disease therapy. The heating instruments for the thermotherapy have developed by using radiation, ultrasound and microwave (MW). However, radiation cause side effect cell ionization. Also, ultrasound has the limitation of heating through a bone. The thermotherapy by using MW provide overcome the reflection on the bone without the risk of ionizing radiation [3, 4].