A novel approach of high-resolution UWB microwave imaging system based on an improved 3D back-projection method for early-stage breast cancer detection applications

Abstract

In this paper, a novel approach of high-accuracy calibration (HAC) method is employed to improve the resolution of tumor detection within a fibro-glandular breast model, and also an improved 3D back-projection approach to scan each focal point inside of the breast is presented. For these purposes, a simulated hemispherical setup of a multi-static array with a modified UWB bowtie antenna is applied around the breast. The superiority of the proposed HAC method is that all-time delays of multi-static channel paths are taken into account at preprocessing of reflected signals, and therefore the time location of tumor response can be estimated accurately in the late stage of recorded signals. As a result, stronger signals are obtained to detect the location of the tumor with higher spatial accuracy. By using the improved 3D back-projection method, a better approximation of transmission channel paths based on Fermat's principle is achieved. A realistic breast model is proposed with two cases of single and twin spherical tumors. Then, to validate the efficiency of the proposed HAC method to detect the time-dependent tumor location, several scenarios are studied in the mentioned model. Quantitative metrics of successfully reconstructed tumor (with a small radius of 7 mm) images prove the ability of the proposed imaging method for early-stage breast cancer detection.

A Novel Approach of a Low-Cost UWB Microwave Imaging System with High Resolution Based on SAR and a New Fast Reconstruction Algorithm for Early-Stage Breast Cancer Detection

“…The breast model consists of a 50 mm radius hemisphere attached to a 2 mm layer that replicates the skin, filled with air. In most medical imaging literature [ 31 , 32 , 33 ], the tumor shape is represented as a spherical object. In this work, a spherical 0.5 cm radius tumor is included.…”

A compact ultrawideband slotted patch antenna for early stage breast tumor detection applications

“…Consequently, a number of 496 time-domain signals from the 31 elements are gathered in the simulation environment. After obtaining the recorded signals, initially, a calibration method is applied according to [62] in order to eliminate the effects of the coupling medium and the skin. Following the calibration, an improved DAS algorithm [5,62] is utilized to reconstruct two-dimensional (2D) and threedimensional (3D) images using the following equation:…”

“…Consequently, a number of 496 time-domain signals from the 31 elements are gathered in the simulation environment. After obtaining the recorded signals, initially, a calibration method is applied according to [62] in order to eliminate the effects of the coupling medium and the skin. Following the calibration, an improved DAS algorithm [5, 62] is utilized to reconstruct two-dimensional (2D) and three-dimensional (3D) images using the following equation:where I ( P f ) is the energy of each scanning focal points, P f within the breast model, τ( p f ) is the time-delay corresponding to each focal point, which is calculated based on the approximated wave speed between each T x and R x antennas [5], w m is applied as a weighting factor to compensate the path-dependent attenuation along T x – R x paths with respect to tissue losses [63], τ p is the integration window which is usually considered a percentage of the excitation pulse width, and M is the total number of available time-domain calibrated signals X m regarding T x – R x paths.…”

Low‐profile aperture stacked patch antenna for early‐stage breast cancer detection applications

“…Therefore, each element of the antenna array as transmitter antennas (Tx) illuminates the breast sequentially while the same and other elements as receiver antennas (Rx) record the scattered signals from the breast model 34,35 . After recording the signals, first, a calibration method based on the proposed algorithm in 36 is applied to remove the artifact effects for each recorded signal, then, an improved Delay‐and‐Sum (DAS) algorithm 36 is applied to detect the breast cancer. The reconstructed 2D and 3D images of the detected tumor are illustrated in Figure 19.…”