Unexpected physical phenomena indicated by FDTD modeling of the Sigma-60 deep hyperthermia applicator

Author

Reuter, Christopher E. ; Taflove, Allen ; Sathiaseelan, Vythialingam ; Piket-May, Melinda ; Mittal, Bharat B.

Author_Institution

Res. Site, U.S. Air Force Res. Lab., Rome, NY, USA

Volume

46

Issue

4

fYear

1998

fDate

4/1/1998 12:00:00 AM

Firstpage

313

Lastpage

319

Abstract

We investigate the numerical convergence properties of two-dimensional (2-D) and three-dimensional (3-D) finite-difference time-domain (FDTD) models of the BSD-2000 Sigma-60 annular phased array used for deep hyperthermia. The FDTD modeling data indicate unexpected physical phenomena for the case of Sigma-60 excitation of an elliptical tissue phantom embedded in a circular water bolus. These phenomena include: (1) high-Q energy storage; (2) electromagnetic (EM) mode flipping within the water bolus/phantom; and (3) whispering-gallery transmission of energy to the opposite side of the phantom relative to the exciting dipole pair. We conclude that these phenomena substantially impact the FDTD numerical modeling of this system, and further conclude that the whispering-gallery effect can impact clinical applications of the Sigma-60

Keywords

convergence of numerical methods; finite difference time-domain analysis; hyperthermia; microwave heating; BSD-2000 Sigma-60 annular phased array; FDTD model; circular water bolus; clinical application; deep hyperthermia applicator; dipole pair excitation; electromagnetic mode flipping; elliptical tissue phantom; energy storage; numerical convergence; whispering-gallery transmission; Convergence of numerical methods; Energy storage; Finite difference methods; Hyperthermia; Imaging phantoms; Numerical models; Phased arrays; Time domain analysis; Two dimensional displays; Water storage;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/22.664132

Filename

664132