Rotationally Adjustable Hyperthermia Applicators: A Computational Comparative Study of Circular and Linear Array Applicators

Gulsah Yildiz*, Tuba Yilmaz, Ibrahim Akduman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Microwave breast hyperthermia (MH) aims to increase the temperature at the tumor location with minimal change in the healthy tissue. To this end, the specific absorption rate ((Formula presented.)) inside the breast is optimized. The choice of the MH applicator design is important for a superior energy focus on the target. Although hyperthermia treatment planning (HTP) changes for every patient, the MH applicator is required to be effective for different breast models and tumor types. The linear applicator ((Formula presented.)) is one of the previously proposed applicator designs with linearly arranged antennas; however, it suffers from low focusing ability in certain breast regions due to its unsymmetrical geometrical features. In this paper, we propose to radially adjust the (Formula presented.) to obtain alternative excitation schemes without actually changing the applicator. Antipodal Vivaldi antennas were utilized, and the antenna excitations were optimized with particle swarm optimization (PSO). The comparison of the rotated and the fixed linear applicator, between 12-antenna circular and linear applicators, and finally, between a 24-antenna circular applicator are provided. Within the 12 rotation angles and two target locations that were analyzed, the 135° axially rotated linear applicator gave a 35% to 84% higher target-to-breast (Formula presented.) ratio ((Formula presented.)) and a 21% to 28% higher target-to-breast temperature ratio ((Formula presented.)) than the fixed linear applicator. For the deep-seated target, the 135° rotated linear applicator had an 80% higher (Formula presented.) and a 59% higher (Formula presented.) than the 12-antenna circular applicator, while the results were comparable to the 24-antenna circular applicator.

Original languageEnglish
Article number2677
Issue number11
Publication statusPublished - Nov 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors.


This work received funding from Scientific and Technological Research Council of Turkey under Grant Agreement 118S074 and COST Action Grant Agreement CA17115.

FundersFunder number
European Cooperation in Science and TechnologyCA17115
Türkiye Bilimsel ve Teknolojik Araştırma Kurumu118S074


    • antenna excitation optimization
    • breast cancer
    • hyperthermia treatment planning
    • microwave hyperthermia
    • particle swarm optimization
    • specific absorption rate focus


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