Ultra-wideband Breast Research Articles

Flexible 16 Antenna Array for Microwave Breast Cancer Detection.

Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2-4 GHz (with reflection coefficient (S11) below -10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively.

Adaptive Combining via Correlation Exploration for Ultrawideband Breast Cancer Imaging

A novel Adaptive Combining via Correlation Exploration (ACE) algorithm of ultrawideband (UWB) imaging for breast cancer detection is proposed. ACE explores and exploits the correlation between backscattered signals and local coherence reference signals generated within each group of neighboring antennas. High-correlation signals are adaptively selected, summed, and weighted by the product of their corresponding coefficients, forming the intensity of each pixel within an imaging area. The efficacy of proposed algorithm is validated on 3-D anatomically and dielectrically accurate finite-difference time-domain (FDTD) breast models. A variety of scenarios, for both homogenous and heterogeneous, sparse and moderately dense breast models, coupled with both ideal and practical artifact removal methods, are considered. The superior performance of ACE in identification of malignant tumors is demonstrated in comparison to delay-and-sum, delay-multiply-and-sum, and filtered delay-and-sum algorithms. The ACE algorithm is shown to be not only immune to early-stage artifact, but also capable of distinguishing responses from cancerous and fibro-glandular tissues, in which the other three techniques suffer significantly or completely fail. This shows the high promise of ACE for breast cancer screening.

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Ultra Wideband Breast Cancer Detection by Using SAR for Indication the Tumor Location

Multiple-Input Multiple-Output Radar for Lesion Classification in Ultrawideband Breast Imaging

This paper studies the problem of applying multiple-input multiple-output (MIMO) radar techniques for lesion classification in ultrawideband (UWB) breast imaging. Ongoing work on this topic has suggested that benign and malignant masses, which usually possess remarkable architectural differences, could be distinguished by exploiting their morphology-dependent UWB microwave backscatter. We have previously approached this problem by deriving the complex natural resonances of the late-time target response, where the damping factors vary with the border profiles of anomalies. In this paper, we investigate the potential advantage of MIMO radar to enhance the resonance scattering phenomenon in breast tissue discrimination. MIMO radar can choose freely the probing signals transmitted via its antennas to exploit the independence between signals at the array elements, thereby enhancing the performance of target classification. Based on the observed damping factors and the receiver operating characteristics at different classifiers, which correspond to various diversity paths in the MIMO radar system, two data-fusion rules are proposed for robust lesion differentiation. Finally, numerical examples are provided to demonstrate the efficacy of the proposed imaging technique.

An overview of radar based ultra wideband breast cancer detection algorithms

Breast cancer is the most common cancer in women in almost all countries around the world, and is one of the most common non-infective causes of death. Mammography, which uses ionising radiation, is the only early breast cancer screening technique proven to reduce breast cancer mortality in randomised controlled clinical trials. However, screening mammography is expensive, technically demanding and requires a high level of clinical expertise. It cannot be performed in general medical clinical settings readily. Ultra wideband (UWB) or microwave breast screening has the potential to be a safe, accurate and easy-to-use technique for breast disease detection that is more effective than routine clinical palpation or breast self-examination. Ultra wideband breast cancer detection algorithms have been researched by several groups for over a decade, with numerous algorithms reported. This paper serves to give an overview of existing algorithms for UWB breast cancer detection.

Time-Reversal Ultrawideband Breast Imaging: Pulse Design Criteria Considering Multiple Tumors With Unknown Tissue Properties

Pulse design is investigated for time-reversal (TR) imaging as applied to ultrawideband (UWB) breast cancer detection. Earlier it has been shown that a suitably-designed UWB pulse may help to improve imaging performance for a single-tumor breast phantom with predetermined lesion properties. The current work considers the following more general and practical situations: presence of multiple malignancies with unknown tumor size and dielectric properties. Four pulse selection criteria are proposed with each focusing on one of the following aspects: eliminating signal clutter generated by tissue inhomogeneities, canceling mutual interference among tumors, improving image resolution, and suppressing artifacts created by sidelobe of the target response. By applying the proposed criteria, the shape parameters of UWB waveforms with desirable characteristics are identified through search of all the possible pulses. Simulation example using a numerical breast phantom, comprised of two tumors and structured clutter distribution, demonstrates the effectiveness of the proposed approach. Specifically, a tradeoff between the image resolution and signal-to-clutter contrast (SCC) is observed in terms of selection of the excitation waveforms.

Effect of Lesion Morphology on Microwave Signature in 2-D Ultra-Wideband Breast Imaging

This paper studies the possibility of distinguishing between benign and malignant masses by exploiting the morphology-dependent temporal and spectral characteristics of their microwave backscatter response in ultra-wideband breast cancer detection. The spiculated border profiles of 2-D breast masses are generated by modifying the baseline elliptical rings based upon the irregularity of their peripheries. Furthermore, the single- and multilayer lesion models are used to characterize a distinct mass region followed by a sharp transition to background, and a blurred mass border exhibiting a gradual transition to background, respectively. Subsequently, the complex natural resonances (CNRs) of the backscatter microwave signature can be derived from the late-time target response and reveal diagnostically useful information. The fractional sequence CLEAN algorithm is proposed to estimate the lesions' delay intervals and identify the late-time responses. Finally, it is shown through numerical examples that the locations of dominant CNRs are dependent on the lesion morphologies, where 2-D computational breast phantoms with single and multiple lesions are investigated. The analysis is of potential use for discrimination between benign and malignant lesions, where the former usually possesses a better-defined, more compact shape as opposed to the latter.

Time of Arrival Data Fusion Method for Two-Dimensional Ultrawideband Breast Cancer Detection

A new microwave imaging method is given for breast tumor detection using an ultrawideband (UWB) imaging system. By combining the time of arrival (TOA) measurements from different sensors, the presence and location of small malignant lesions can be identified. At each sensor, the generalized sequence CLEAN (GS-CLEAN) algorithm is proposed to resolve the impulse response (IR) components into bins smaller than the duration of the sounding pulse. This novel deconvolution technique, working well with largely continuous image content, also solves an inverse problem to estimate the unknown tumors' morphological/dielectric properties and delay intervals. Subsequently, the TOA data fusion step is applied to obtain an estimate of the locations of dominant scattering sources such as cancerous tumors. We also apply the entropy-based approaches to collectively estimate the tumor morphological and electrical features based on the information acquired at various antenna elements. Preliminary two-dimensional (2-D) analysis and simulations demonstrate that the system developed is feasible to detect small breast malignant masses using this approach.

Co-polarised and cross-polarised antenna arrays for breast, cancer detection

The detection capabilities of two novel co-polarised and cross-polarised antenna arrays consisting of two slot antennas have been studied and compared for the purpose of ultra-wideband breast cancer detection. For both arrays, the measured antenna return loss is below −10 dB from 3.1 to 10 GHz. The measured coupling between the two elements is below −20 dB for the co-polarised and −25 dB for the cross-polarised formation. It is shown through simulations and measurements that the cross-polarised array improves the signal-to-clutter ratio for tumours close to a planar chest wall.