A Novel Measurement Technique for the Broadband Characterization of Diluted Water Ferrofluids for Biomedical Applications

Review of Microwaves Techniques for Breast Cancer Detection

“…With the advancement of the nanotechnology field and nanomaterials, several studies [31][32][33] proposed and investigated the possibility of improving the available cancer detection methods (magnetic resonance imaging (MRI), magneto-acoustic tomography (MAT), computed tomography (CT), and near-infrared (NIR) imaging) by combining the detection method with magnetic nanoparticle materials that are biocompatible such as iron oxide nanoparticles. In microwave detection for breast cancer, some recent studies explored the advantages of using magnetic nanoparticles to improve the contrast between the dielectric properties of normal, benign, and malignant breast tissues, as well as the in vivo and ex vivo states of breast tissues [31][32][33][34].…”

Enhanced Detection of Magnetic Nanoparticles Using a Novel Microwave Ferromagnetic Resonance Imaging System

“…where γ is the gyromagnetic ratio and H a is the anisotropy field given by H a = Table 4.1 were either provided by the manufacturer (Ferrotec R product EMG1300) or estimated from the literature for similar MNPs. Again, we refer the reader to [2] for a more complete description of these properties' relationships to the quantities shown in Although there are further modifications to (4.2) and (4.3) described elsewhere that fully account for the addition of PMF dependency [103], it is adequate to note that the application of a PMF both attenuates the resonance signal and shifts its peak This "quenching" phenomenon increases with greater PMF magnitude; it is this effect that motivates research on imaging of differential data using MNPs [2,28,37,[94][95][96].…”

“…In this case, at an imaging frequency of 2.15 GHz chosen based on experimental observations described later, with the PMF "off", the magnetic susceptibility for The experimental procedure was carried out in much the same capacity as outlined in [2], though as the adapters used were commercial products and not custom-made, two adjacent holes needed to be drilled in close proximity through the outer shielding of the female-to-female N-type adapter into the air cavity formed by mating to the male adapter, to allow filling and for air to escape; the custom-made measurement cell in [2] had sufficient room to allow the air and filling holes to be on opposite ends of the cavity.…”

“…ENA for the ferrofluid-filled cavity placed within the bore of the electromagnet, and collected without any applied magnetic field, and with a steadily increasing PMF at increments of 50 Gauss until a maximum strength of 2000 Gauss was reached. These measurements were processed according to the procedure outlined in [2], ultimately based on treating the cavity formed by the N-type adapters mathematically as an annular disk of dielectric material within a transmission line, as in [104].…”

Quantifying the complex permittivity and permeability of magnetic nanoparticles

“…[5][6][7] However, values of the required parameters are often an open question as they could be significantly affected by the material, size and measuring device fabrication process.[7] To effectively utilize magnetic nanoparticles for biomedical applications over the frequencies of interest (often in the microwave regime) it is important to accurately characterize not only the magnetic response quantified by the permeability of the nanoparticles, but also the electric response ascertained by the permittivity. [8] Transmission methods could be used for determining the permittivity (ǫ) and permeability (µ) of material over the requisite wide range of frequencies.[8-10] Usually, ǫ and µ are obtained by measuring reflection and transmission coefficients in free space or via waveguide. Calibration is required to adjust the reference plane to sample surfaces using complicated, multi-step processes includ-ing through-reflection-line calibration, which demand expert technique and complex instrumentation.[10] Irrespective of calibration, an accurate measurement of ǫ and µ is very challenging for nanoparticles due to the nanoscale sizes and amounts (typically several mg); the intrinsic nanoparticle scales are usually much smaller than the wavelength range of measurement frequencies.…”