The Application of an Iterative Structure to the Delay-and-Sum and the Delay-Multiply-and-Sum Beamformers in Breast Microwave Imaging

Abstract

Breast microwave imaging (BMI) is a potential breast cancer screening method. This manuscript presents a novel iterative delay-and-sum (DAS) based reconstruction algorithm for BMI. This iterative-DAS (itDAS) algorithm uses a forward radar model to iteratively update an image estimate. A variation of the itDAS reconstruction algorithm that uses the delay-multiply-and-sum (DMAS) beamformer was also implemented (the itDMAS algorithm). Both algorithms were used to reconstruct images from experimental scans of an array of 3D-printed MRI-based breast phantoms performed with a clinical BMI system. The signal-to-clutter ratio (SCR) and signal-to-mean ratio (SMR) were used to compare the performance of the itDAS and itDMAS methods to the DAS and DMAS beamformers. While no significant difference between the itDAS and itDMAS methods was observed in most images, the itDAS algorithm produced reconstructions that had significantly higher SMR than the non-iterative methods, increasing contrast by as much as 19 dB over DAS and 13 dB over DMAS. The itDAS algorithm also increased the SCR of reconstructions by up to 5 dB over DAS and 4 dB over DMAS, indicating that both high-intensity and background clutter are reduced in images reconstructed by the itDAS algorithm.

A Simulation-Based Methodology of Developing 3D Printed Anthropomorphic Phantoms for Microwave Imaging Systems

“…As defined in the framework of the EMERALD project, the manufacturing process used to build up accurate ultra-wideband (UWB) phantoms has to be easily reproducible by an electrical engineer in a non-specific environment without extreme precautions, and to some extent at low cost. The specificity of the GeePs-L2S breast phantom and those suggested in our previous and current works on the head [ 19 , 32 ], breast [ 13 , 33 ], and thorax [ 34 , 35 ] phantoms, has been confirmed by the work of [ 14 , 15 , 16 , 17 , 18 ] and [ 36 , 37 , 38 , 39 ]. These phantoms composed of several 3D printed cavities are filled up with liquid mixtures made for example of Triton X-100 (TX-100, a non-ionic surfactant) and salt water, the concentrations are numerically adjusted so that the dielectric properties are close to the reference values over a wide frequency range.…”

“…Burfeindt et al, have given the scientific community access to an STL file of a breast phantom [ 12 ] made of a unique cavity. This gave rise to the 3 cavities GeePs-L2S breast phantom [ 13 ] which is designed and developed by using CAD software from the STL file in open access and whose printed form was in turn shared within the framework of COST TD1301 MiMed to test several microwave imaging systems in development [ 14 , 15 , 16 , 17 , 18 ].…”

Microwave Breast Imaging Using Compressed Sensing Approach of Iteratively Corrected Delay Multiply and Sum Beamforming

“…The improvements of DMAS over DAS has been proven in [ 13 , 17 ]. The iterative variant of DAS and DMAS is proposed in [ 18 ] where the authors removed the background clutter in the reconstructed images. The reconstructed images of the DMAS algorithm were used to detect the tumor after normalizing the maximum scatterer [ 19 ].…”

Parallel Delay Multiply and Sum Algorithm for Microwave Medical Imaging Using Spark Big Data Framework

“…The advantages of using DMAS over DAS has been proven in [20,21]. The iterative variant of DMAS was proposed in [22], where the background clutter was removed in the resulting images. Due to its advantages, DMAS is used in many research works instead of DAS [22].…”

“…The iterative variant of DMAS was proposed in [22], where the background clutter was removed in the resulting images. Due to its advantages, DMAS is used in many research works instead of DAS [22]. The downside of using DMAS in comparison to DAS is the significant increase in computational load [23].…”