Microwave thermometry with potential application in non-invasive monitoring of hyperthermia

Morteza Ghaderi Aram,Hana Dobsicek Trefna,Larisa Beilina

doi:10.1515/jiip-2020-0102

Abstract

Abstract Integration of an adaptive finite element method (AFEM) with a conventional least squares method has been presented. As a 3D full-wave forward solver, CST Microwave Studio has been used to model and extract both electric field distribution in the region of interest (ROI) and S-parameters of a circular array consisting of 16 monopole antennas. The data has then been fed into a differential inversion scheme to get a qualitative indicator of how the temperature distribution evolves over a course of the cooling process of a heated object. Different regularization techniques within the Tikhonov framework are also discussed, and a balancing principle for optimal choice of the regularization parameter was used to improve the image reconstruction quality of every 2D slice of the final image. Targets are successfully imaged via proposed numerical methods.

Highlights

Microwave hyperthermia [17] has shown to be a good candidate to help increase therapeutic gains of traditional cancer therapies like radio- and chemo-therapy [11, 13]
As a 3D full-wave forward solver, CST Microwave Studio has been used to model and extract both electric field distribution in the region of interest (ROI) and S-parameters of a circular array consisting of 16 monopole antennas
The standard scheme has been supplemented by adaptive finite element method (AFEM) to gain higher quality reconstructions during the course of the cooling process of a heated object

Summary

Introduction

Microwave hyperthermia [17] has shown to be a good candidate to help increase therapeutic gains of traditional cancer therapies like radio- and chemo-therapy [11, 13] It aims to increase the tumor temperature to therapeutic levels of 40–44 °C while keeping healthy tissue at the normothermic temperatures. To control and evaluate the quality of the treatment in terms of achieved temperatures in tumor as well as healthy tissues, thermal dose monitoring is a critical instance of the treatment. To this end, a robust and preferably real-time feedback control that helps to adjust the focal point in the target is warranted. Several methods have been proposed in the literature among which the invasive measurements in tumor-related reference points [7, 21, 27] and MR-guided thermometry [10, 14, 32] are currently in clinical use

Methods

Results

Conclusion