Coherent 3×3 planar array of water-loaded box-horns for hyperthermia treatment of cancer

Abstract

In this paper, the authors have proposed a 3×3 planar array of water-loaded box-horns for hyperthermia treatment of tumor. The box-horn consists of a TE10 mode H-plane sectoral-horn coupled to a length L of rectangular waveguide of same E-plane height but whose H-plane width is large enough to support the TE30 mode. Thus box-horn supports TE 10p and TE30 modes resulting in relatively uniform amplitude distribution over the H-plane of the aperture to prevent steep heating gradient in bio-medium. Expression for electric field in muscle due to planar array of box-horns is derived using two different techniques, i.e., Fresnel-Kirchhoff scalar diffraction field theory and plane wave spectral technique. SAR distributions in different planes of heating medium due the array applicator are evaluated at 2.45 GHz using these techniques. The results for SAR distribution of the planar array of box-horns are also compared with those for single box-horn. The results for SAR distribution in z-direction demonstrate that tumor at greater depth can be heated with the planar array of box-horns due to increased penetration depth in comparison to a single box-horn. Also planar array has wider area of illumination and higher peak value of SAR in both x- and y-directions as compared with a single box-horn. It is shown that the results obtained by these two techniques are in agreement with each other. © 2006 JD.