High-Frequency (30 MHz–6 GHz) Breast Tissue Characterization Stabilized by Suction Force for Intraoperative Tumor Margin Assessment

A gigahertz (GHz) range antenna formed by a coaxial probe has been applied for sensing cancerous breast lesions in the scanning platform with the assistance of a suction tube. The sensor structure was a planar central layer and a metallic sheath of size of 3 cm2 connected to a network analyzer (keySight FieldFox N9918A) with operational bandwidth up to 26.5 GHz. Cancer tumor cells have significantly higher water content (as a dipolar molecule) than normal breast cells, changing their polarization responses and dielectric losses to incoming GHz-based stimulation. Principal component analysis named S11, related to the dispersion ratio of the input signal, is used as a parameter to identify malignant tumor cells in a mouse model (in vivo) and tumor specimens of breast cancer patients (in vitro) (both central and marginal parts). The results showed that S11 values in the frequency range from 5 to 6 GHz were significantly higher in cancer-involved breast lesions. Histopathological analysis was the gold standard for achieving the S11 calibration to distinguish normal from cancerous lesions. Our calibration on tumor specimens presented 82% positive predictive value (PPV), 100% negative predictive value (NPV), and 86% accuracy. Our goal is to apply this system as an in vivo non-invasive tumor margin scanner after further investigations in the future

Intraoperative Assessment of High-Risk Thyroid Nodules Based on Electrical Impedance Measurements: A Feasibility Study

Precise diagnosis of thyroid nodules is challenging due to non-diagnostic/inconclusive results and uncertainties about the malignancy of follicular neoplasms (FNs), even in frozen-section pathology. Therefore, surgical management, especially in Bethesda III and IV categories, may be complicated, and sometimes a second surgery may be required. The Thyroid Nodule Impedance Measurement System (TN-IMS) consists of a metallic patch attached to submental skin and a G20 I.V. cannula inserted into the targeted nodules. Two impedance-based parameters named Z1kHz and impedance phase slope (IPS) in 100 kHz to 500 kHz of the thyroid nodules are recorded and compared with their histopathological results as the gold standard. TN-IMS was intra-surgically applied to 103 human thyroid nodules and normal thyroid tissues. A remarkable consistency between defined co-ranges of Z1kHz/IPS and the histopathological status of specimens was achieved (p < 0.001). Based on these measurements, it was concluded that intraoperative bioelectrical impedance scanning of thyroid nodules would be a helpful complementary approach to detecting high-risk excision-required thyroid nodules