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

A Preliminary Study of Ultrasound-Guided Microwave Ablation for Nonpuerperal Mastitis Treatment

Introduction

This study investigated the feasibility of ultrasound (US)-guided microwave ablation (MWA) as a treatment for nonpuerperal mastitis (NPM).

Methods

Fifty-three patients with NPM diagnosed by biopsy and treated with US-guided MWA at the Affiliated Hospital of Nantong University between September 2020 and February 2022 were classified according to whether they underwent MWA alone (n = 29) or MWA with incision and drainage (n = 24). Patients were followed up by interviews, physical and US examinations, and evaluation of breast skin at 1 week and 1, 2, and 3 months after treatment. Data from these patients were prospectively collected and retrospectively analyzed.

Results

The overall mean patient age was 34.42 ± 9.20 years. The groups differed significantly by age, involved quadrants, and the initial maximum diameter of lesions. In the MWA group, the cure rate was 34.48%, and the apparent efficiency rate was 65.52%. In the MWA with incision and drainage, the apparent efficiency rate was 91.66%, and the effective rate was 4.17%. The excellent rate for breast aesthetics in the MWA group was 79.31%, and the good rate was 20.69%. The excellent rate in the MWA with incision and drainage group was 45.83%, the good rate was 41.67%, and the qualified rate was 12.5%. The mean maximum diameter of lesions in the two groups decreased significantly.

Conclusion

For NPM with small lesions in a single quadrant, MWA therapy is a direct and effective method. For larger lesions involving two or more quadrants, the combined treatment of MWA with incision and drainage showed significant improvement in a short period. MWA treatment of NPM has importance for further research and clinical applications.

High-Resolution Detection of Rock-Forming Minerals by Permittivity Measurements with a Near-Field Scanning Microwave Microscope

The identification of the minerals composing rocks and their dielectric characterization is essential for the utilization of microwave energy in the rock industry. This paper describes the use of a near-field scanning microwave microscope with enhanced sensitivity for non-invasive measurements of permittivity maps of rock specimens at the micrometer scale in non-contact mode. The microwave system comprises a near-field probe, an in-house single-port vectorial reflectometer, and all circuitry and software needed to make a stand-alone, portable instrument. The relationship between the resonance parameters of the near-field probe and the dielectric properties of materials was determined by a combination of classical cavity perturbation theory and an image charge model. The accuracy of this approach was validated by a comparison study with reference materials. The device was employed to determine the permittivity maps of a couple of igneous rock specimens with low-loss and high-loss minerals. The dielectric results were correlated with the minerals comprising the samples and compared with the dielectric results reported in the literature, with excellent agreements.