A Pilot Study of the Impact of Microwave Ablation on the Dielectric Properties of Breast Tissue

Luz Maria Neira; R. Owen Mays; James F. Sawicki; Amanda Schulman; Josephine Harter; Lee G. Wilke; Nader Behdad; Barry D. Van Veen; Susan C. Hagness

doi:10.3390/s20195698

Sensors (Oct 2020)

A Pilot Study of the Impact of Microwave Ablation on the Dielectric Properties of Breast Tissue

Luz Maria Neira,
R. Owen Mays,
James F. Sawicki,
Amanda Schulman,
Josephine Harter,
Lee G. Wilke,
Nader Behdad,
Barry D. Van Veen,
Susan C. Hagness

Affiliations

Luz Maria Neira: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA
R. Owen Mays: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA
James F. Sawicki: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA
Amanda Schulman: Department of Surgery, University of Wisconsin, Madison, WI 53792, USA
Josephine Harter: Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI 53792, USA
Lee G. Wilke: Department of Surgery, University of Wisconsin, Madison, WI 53792, USA
Nader Behdad: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA
Barry D. Van Veen: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA
Susan C. Hagness: Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706, USA

DOI: https://doi.org/10.3390/s20195698
Journal volume & issue: Vol. 20, no. 19
p. 5698

Abstract

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Percutaneous microwave ablation (MWA) is a promising technology for patients with breast cancer, as it may help treat individuals who have less aggressive cancers or do not respond to targeted therapies in the neoadjuvant or pre-surgical setting. In this study, we investigate changes to the microwave dielectric properties of breast tissue that are induced by MWA. While similar changes have been characterized for relatively homogeneous tissues, such as liver, those prior results are not directly translatable to breast tissue because of the extreme tissue heterogeneity present in the breast. This study was motivated, in part by the expectation that the changes in the dielectric properties of the microwave antenna’s operation environment will be impacted by tissue composition of the ablation target, which includes not only the tumor, but also its margins. Accordingly, this target comprises a heterogeneous mix of malignant, healthy glandular, and adipose tissue. Therefore, knowledge of MWA impact on breast dielectric properties is essential for the successful development of MWA systems for breast cancer. We performed ablations in 14 human ex-vivo prophylactic mastectomy specimens from surgeries that were conducted at the UW Hospital and monitored the temperature in the vicinity of the MWA antenna during ablation. After ablation we measured the dielectric properties of the tissue and analyzed the tissue samples to determine both the tissue composition and the extent of damage due to the ablation. We observed that MWA induced cell damage across all tissue compositions, and found that the microwave frequency-dependent relative permittivity and conductivity of damaged tissue are lower than those of healthy tissue, especially for tissue with high fibroglandular content. The results provide information for future developments on breast MWA systems.

Published in Sensors

ISSN: 1424-8220 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Chemical technology
Website: http://www.mdpi.com/journal/sensors

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