Microwave imaging of breast cancer with factorization method: SPIONs as contrast agent

Abstract

Female breast at macroscopic scale is a nonmagnetic medium, which eliminates the possibility of realizing microwave imaging of the breast cancer based on magnetic permeability variations. However, by administering functionalized, superparamagnetic iron oxide nanoparticles (SPIONs) as a contrast material to modulate magnetic permeability of cancer cells, a small variation on the scattered electric field from the breast is achievable under an external, polarizing magnetic field. Purpose: We demonstrate an imaging technique that can locate cancerous tumors inside the breast due to electric field variations caused by SPION tracers under different magnetic field intensities. Furthermore, we assess the feasibility of SPION-enhanced microwave imaging for breast cancer with simulations performed on a multi-static imaging configuration. Methods: The imaging procedure is realized as the factorization method of qualitative inverse scattering theory, which is essentially a shape retrieval algorithm for inaccessible objects. The formulation is heuristically modified to accommodate the scattering parameters instead of the electric field to comply with the requirements of experimental microwave imaging systems. Results: With full-wave electromagnetic simulations performed on an anthropomorphically realistic breast phantom, which is excited with a cylindrical imaging prototype of 18 dipole antenna arranged as a single row, the technique is able to locate cancerous tumors for a experimentally achievable doses. Conclusions:The technique generates nonanatomic microwave images, which map the cancerous tumors depending on the concentration of SPION tracers, to aid the diagnosis of the breast cancer.

Single‐Particle Characterization by Elastic Light Scattering

“…[ 70,242 ] On the other hand, various advanced methods have also been applied, such as the linear sampling method, [ 243,244 ] the contrast source inversion method, [ 245,246 ] and the factorization method. [ 247,248 ] However, it is still unclear whether these methods can be applied at optical frequencies, although the interference‐based measurement of field phases is possible. [ 249,250 ]…”

Determination of electromagnetic source localization with factorization method

“…where {λ 1 ,λ 2 ,...,λ N }, {ψ 1 , ψ 2 ,..., ψ N } denotes the eigenvalues and the eigenvectors of F, respectively. It is proven that (7) has a finite solution only when the indicator function in (9) diverges from zero as discussed in [31][32][33][34]36].…”

“…Imaging of inaccessible objects which play a key role in many different applications such as remote sensing, subsurface imaging, and non-destructive testing is an essential problem that has been investigated for a long time [1][2][3][4][5][6][7][8]. Microwave imaging (MWI) is an emerging technology which focuses on shape reconstruction and capturing electrical properties of concealed targets [1,8,9]. Many MWI methods have been proposed in order to obtain imaging results of investigated problems such as screening of cancerous tissues and detection of land mines.…”

Holographic Microwave Image Classification Using a Convolutional Neural Network

“…Microwave imaging has been proposed as one of the most potential breast imaging tools [4]. Researchers have extensively investigated microwave imaging in many aspects, including measurement of the microwave dielectric properties of breast tissues [5,6], image algorithms [7,8], numerical models [9,10], data acquisition systems [11][12][13], microwave antennas [14][15][16], clinical trials [17,18], image enhancement and improvement methods [19][20][21], and image classification [22][23][24]. If microwave images contain specific qualitative and quantitative indicators, this may help characterize benign and malignant tumors and predict disease.…”