The correlation ofin vivoandex vivotissue dielectric properties to validate electromagnetic breast imaging: initial clinical experience

Abstract

Electromagnetic (EM) breast imaging provides low-cost, safe and potentially a more specific modality for cancer detection than conventional imaging systems. A primary difficulty in validating these EM imaging modalities is that the true dielectric property values of the particular breast being imaged are not readily available on an individual subject basis. Here, we describe our initial experience in seeking to correlate tomographic EM imaging studies with discrete point spectroscopy measurements of the dielectric properties of breast tissue. The protocol we have developed involves measurement of in vivo tissue properties during partial and full mastectomy procedures in the operating room (OR) followed by ex vivo tissue property recordings in the same locations in the excised tissue specimens in the pathology laboratory immediately after resection.We have successfully applied all of the elements of this validation protocol in a series of six women with cancer diagnoses. Conductivity and permittivity gauged from ex vivo samples over the frequency range 100 Hz-8.5 GHz are found to be similar to those reported in the literature. A decrease in both conductivity and permittivity is observed when these properties are gauged from ex vivo samples instead of in vivo. We present these results in addition to a case study demonstrating how discrete point spectroscopy measurements of the tissue can be correlated and used to validate EM imaging studies.

Numerical Modelling for Ultra Wideband Radar Breast Cancer Detection and Classification

“…In [41], it was observed that the dielectric properties for normal breast tissue estimated in scenario (i) agreed with the findings from previous studies, such as Lazebnik's [15]. Furthermore, the estimations of dielectric properties in scenario (iii) also agreed well with previous ex vivo studies such as [37,38,40,42].…”

“…In addition, in 2009, Halter et al [41] presented the initial results from a clinical study with a smaller number of patients in which estimates of the dielectric properties of malignant breast tissue were obtained in three different scenarios. The dielectric properties were taken in the following scenarios: (i) by estimation means of Electrical Impedance Tomography imaging, (ii) by direct measurement in vivo breast cancer using both Electrical Impedance Spectroscopy (EIS) and Microwave Impedance Spectroscopy (MIS) probes, and finally (iii) by direct measurement in ex vivo breast cancer specimens with both EIS and MIS probes.…”

“…Multiple spectra recorded for EIS are shown, while the average MIS spectrum is illustrated. Images are reproduced from [41].…”

System Development of Microwave Induced Thermo-Acoustic Tomography and Experiments on Breast Tumor

“…8(b). It can be found that the image contrast between the cancer tissue and the normal tissue is more than 12 dB, which closely reflects the electromagnetic parameters of the normal and cancer tissues [24]. This comparison between thermoacoustic imaging and ultrasound imaging indicates that the thermoacoustic image has very strong advantage on high contrast.…”

Comparison of Radar and Thermoacoustic Technique in Microwave Breast Imaging

“…Previous studies of the MR and MITA techniques have focused on cases with significant contrast in the permittivity and conductivity between malignant and healthy tissue and mild tissue heterogeneity. Although the exactly dielectric characteristics of breast tissue in the microwave range have been a subject of debate [2][3][4], the performance of the MR and MITA technique in the presence of possible tissue heterogeneity deserves more careful analysis.…”