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ORIGINAL RESEARCH ARTICLE

Clinical evaluation of microwave breast imaging using scattering tomography

Yoshihiko Kuwahara1* ,  Kimihito Fujii1
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1 Division of Breast and Endocrine Surgery, Department of Surgery, Faculty of Medicine, Aichi Medical University, Nagakute, Aichi, Japan
Tumor Discovery, 025330080 https://doi.org/10.36922/TD025330080
Received: 14 August 2025 | Revised: 11 December 2025 | Accepted: 12 January 2026 | Published online: 9 February 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Microwave imaging has attracted increasing attention as a breast tumor detection modality because it is non-ionizing and poses minimal risk to the human body. In particular, microwave tomography, which is based on solving the inverse scattering problem, enables visualization of the internal structure of tissues and is therefore expected to have a significant clinical potential. However, the practical implementation of microwave tomography has been hindered by the extremely small scattered-field variations produced by small malignant lesions within lossy breast tissue, as well as unavoidable modeling errors in numerical simulations of the human body and the imaging system. In this study, we introduce a clinically operable microwave breast imaging device that incorporates two key innovations: (i) A highly sensitive dual-polarized antenna array designed to enhance the detectability of weak scattered fields, and (ii) a robust inversion algorithm capable of reconstructing permittivity distributions under substantial modeling and measurement uncertainties. After outlining the relevant electromagnetic properties of breast tissue, we describe how these integrated hardware and software innovations overcome the limitations that have prevented earlier systems from achieving clinical performance. Finally, we summarize clinical results obtained from 24 breast tumor patients. The prototype achieved a sensitivity of 58%, surpassing that of X-ray mammography (40%) in the same cohort, demonstrating the practical potential of our innovation-driven approach to microwave breast imaging.

Keywords
Microwave imaging
Breast cancer
Complex permittivity
Inverse scattering problem
Horn antenna
Calibration
Funding
This study was conducted with the support of the Science and Technology Research Grant of Japan (grant number: 24K10872).
Conflict of interest
The authors declare they have no competing interests.
References
  1. Pastorino M. Microwave Imaging. Hoboken, New Jersey: John Wiley and Sons; 2010.

 

  1. Shao W, McCollough T. Advances in microwave near-field imaging: Prototypes, systems, and applications. IEEE Microw Mag. 2020;3:94-119. doi: 10.1109/mmm.2020.2971375

 

  1. Wang Z, Lim EG, Tang Y, Leach M. Medical applications of microwave imaging. ScientificWorldJournal. 2014;2014:147016. doi: 10.1155/2014/147016

 

  1. Pisa S, Pittella E, Piuzzi E. A survey of radar systems for medical applications. IEEE Aerosp Electron Syst Mag. 2016;31:64-81. doi: 10.1109/maes.2016.140167

 

  1. Umirzakova S, Shakhnoza M, Sevara M, Whangbo TK. Deep learning for multiple sclerosis lesion classification and stratification using MRI. Comput Biol Med. 2025;192:110078. doi: 10.1016/j.compbiomed.2025.110078

 

  1. Hsu H, Lee KH, Karmakar R, et al. From innovation to application: Can emerging imaging techniques transform breast cancer diagnosis? Diagnostics (Basel). 2025;15(21):2718. doi: 10.3390/diagnostics15212718

 

  1. Foundation for Promotion of Cancer Research. Cancer Statistics in Japan. Available from: https://ganjoho.jp/public/ qa_links/report/statistics/2024_en.html [Last accessed on 2025 Nov 19].

 

  1. Sharyl J, Nass I, Henderson C, Lashof JC, editors. Mammography and Beyond: Developing Technologies for the Early Detection of Breast Cancer. Washington, DC: National Academies Press; 2001.

 

  1. Gabriel C, Gabriel S, Corthout E. The dielectric properties of biological tissues: I. Literature survey. Phys Med Biol. 1996;41:2231-2249. doi: 10.1088/0031-9155/41/11/001

 

  1. Gabriel S, Lau RW, Gabriel C. The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz. Phys Med Biol. 1996;41:2251-2269. doi: 10.1088/0031-9155/41/11/002

 

  1. Gabriel S, Law RW, Gabriel C. The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues. Phys Med Biol. 1996;41:2271-2293. doi: 10.1088/0031-9155/41/11/003

 

  1. Popovic D, McCartney L, Beasley C, et al. Precision open-ended coaxial probes for in vivo and ex vivo dielectric spectroscopy of biological tissues at microwave frequencies. IEEE Trans Microw Theory Tech. 2005;53:1713-1722. doi: 10.1109/tmtt.2005.847111

 

  1. Kuwahara Y, Nozaki A, Fujii K. Measurement and Analysis of Complex Permittivity of Breast Cancer in Microwave Band. In: 41st Annual International Conference of the IEEE Engineering in Medicine Biology Conference; 2019. doi: 10.1109/embc.2019.8857791

 

  1. Kuwahara Y, Miura S, Nishina Y, Mukumoto K, Ogura H, Sakahara H. Clinical setup of microwave mammography. IEICE Trans Commun. 2013;E96-B(10):2553-2562. doi: 10.1587/transcom.E96.B.2553.

 

  1. Shea JD, Kosmas P, Van Veen BD, Hagness SC. Contrast-enhanced microwave imaging of breast tumors: A computational study using 3-D realistic numerical phantoms. Inverse Probl. 2010;26:74009. doi: 10.1088/0266-5611/26/7/074009

 

  1. Fuqiang G, Van Veen BD, Hagness SC. Sensitivity of the distorted Born iterative method to the initial guess in microwave breast imaging. IEEE Trans Antennas Propag. 2015;63(8):3540-3547. doi: 10.1109/tap.2015.2436406

 

  1. Li X, Bond EJ, Van Veen BD, Hagness SC. An overview of ultra-wideband microwave imaging via space-time beamforming for early-stage breast-cancer detection. IEEE Antennas Propag Mag. 2005;47(1):19-34. doi: 10.1109/map.2005.1436217

 

  1. Hansen CL. Rank-Deficient and Discrete Ill-Posed Problems: Numerical Aspects of Linear Inversion. Philadelphia, PA: Society for Industrial and Applied Mathematics; 1998.

 

  1. Chen X. Ill-posed problems and regularization. In: Pastorino M, editor. Computational Methods for Electromagnetic Inverse Scattering. Piscataway, NJ: Wiley- IEEE Press; 2017. p. 123-145.

 

  1. Kuwahara Y, Nozaki A, Fujii K. Large-scale analysis of complex permittivity of breast cancer in microwave band. Adv Breast Cancer Res. 2020;9:101-109. doi: 10.4236/abcr.2020.94008

 

  1. Kuwahara Y, Nozaki A. Effectiveness of Folded Quasi Self-Complementary Antenna to Microwave Imaging. In: 2020 14th European Conference on Antennas and Propagation (EuCAP). 2020:1-4. doi: 10.23919/eucap48036.2020.9136049

 

  1. Joachimowicz N, Pichot C, Hugonin JP. Inverse scattering: An iterative numerical method for electromagnetic imaging. IEEE Trans Antennas Propag. 1991;39(12):1742-1752. doi: 10.1109/8.121595

 

  1. Kuwahara Y, Fujii K. Practical technologies for breast cancer detection using scattering tomography. IEICE Trans. 2023;JB106(11):669-676. doi: 10.14923/transcomj.2023API0001.

 

  1. Boulerbah R, Chaabane A, Al-Naib I, Alqadami AS, Aissaoui D, Attia H. Recent advancements in breast cancer detection: A holistic review of microwaves, ultrasound, and photo-acoustic imaging techniques. IEEE J Microw. 2025;5(4):776-792. doi: 10.1109/jmw.2025.3580503

 

  1. Kuwahara Y. Microwave Mammography with a Small Sensor and a Commercial Electromagnetic Simulator. In: 2016 46th European Microwave Conference (EuMC). 2016:663-666. doi: 10.1109/eumc.2016.7824430

 

  1. Murata Software. Available from: https://www. muratasoftware.com/en [Last accessed on 2026 Feb 05].

 

  1. MathWorks MATLAB. Available from: https://jp.mathworks. com/products/matlab.html [Last accessed on 2026 Feb 05]. 28. Kuwahara Y. Application of S-Parameters to the Inverse Scattering Problem. In: 2017 11th European Conference on Antennas and Propagation (EuCAP). 2017:1061-1064. doi: 10.23919/eucap.2017.7928406

 

  1. Mohamed L, Ozawa N, Ono Y, Kamiya T, Kuwahara Y. Study of multi-polarization in microwave tomography for breast cancer detection. IEICE Trans Commun. 2016; 99(8):393-401.

 

  1. Kuwahara Y, Osaki T, Nozaki A, Fujii K. Utilization of preliminary knowledge in microwave tomography for breast cancer detection. IEICE Trans. 2018;J102-C(4):86-92.

 

  1. Kuwahara Y, Fujii K. A Microwave Imaging Sensor Composed of a Dielectric-Loaded Double-Polarized Horn Antenna. In: 2023 17th European Conference on Antennas and Propagation (EuCAP). 2023:1-4. doi: 10.23919/eucap57121.2023.10133433

 

  1. Kuwahara Y, Fujii K. Clinical Imaging by the Microwave Mammography. In: 2025 IEEE MTT-S International Microwave Biomedical Conference (IMBioC). 2025:1-3. doi: 10.1109/IMBioC63524.2025.10989708

 

  1. Kuwahara Y, Suzuki K, Horie H, Hatano H. Conformal Array Antenna with Aspirator for Microwave Mammography. In: 2010 IEEE Antennas and Propagation Society International Symposium. 2010:1-4. doi: 10.1109/APS.2010.5561879

 

  1. Jin J. The Finite Element Method in Electromagnetics. New York: John Wiley and Sons; 2002.

 

  1. Kuwahara Y, Fujii K. Microwave imaging with inverse scattering: Clinical imaging by microwave mammography. IEICE Tech Rep. 2024;124(252):AP2024-AP2140.

 

  1. Gilmore C, Zakaria A, Mojabi P, Ostadrahimi M, Pistorius S, Lo Vetri J. The university of manitoba microwave imaging repository: A two-dimensional microwave scattering database for testing inversion and calibration algorithms [measurements corner]. IEEE Antennas Propag Mag. 2011;53(5):126-133. doi: 10.1109/map.2011.6138442

 

  1. Lehman CD, Isaacs C, Schnall MD, et al. Cancer yield of mammography, MR, and US in high-risk women: Prospective multi-institution breast cancer screening study. Radiology. 2007;244(2):381-388. doi: 10.1148/radiol.2442060461

 

  1. Nguyen PT, Abbosh AM, Crozier S. 3-D focused microwave hyperthermia for breast cancer treatment with experimental validation. IEEE Trans Antennas Propag. 2017;65(7):3489-3500. doi: 10.1109/tap.2017.2700164

 

  1. Li J, Wang B, Zhang D, et al. A preclinical system prototype for focused microwave breast hyperthermia guided by compressive thermoacoustic tomography. IEEE Trans Biomed Eng. 2021;68(7):2289-2300. doi: 10.1109/tbme.2021.3059869
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Tumor Discovery, Electronic ISSN: 2810-9775 Print ISSN: 3060-8597, Published by AccScience Publishing
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