Non-Destructive Characterization of Magnetic Polymeric Scaffolds using Terahertz Time-of-Flight Imaging

Magnetic Scaffolds MagS are 3D composite materials, in which magnetic nanoparticles (MNPs) are used to load a polymeric matrix. Due to their wide use in various medical applications, there is an increasing demand of advanced techniques for non-destructive quality assessment procedures aimed at verifying the absence of defects and, more generally, dedicated to the characterization of MagS. In this framework, the use of TeraHertz (THz) waves for the non-destructive characterization of multifunctional scaffolds represents an open challenge for the scientific community. This paper deals with an approach for the characterization of MagS by means of a THz time-domain system used in reflection mode. THz analyses are performed on poly($\epsilon$ - capprolactone) (PCL) scaffolds magnetized with iron oxide (Fe $_{3}$ O$_{4}$) MNPs through a drop-casting deposition and tuned to obtain different distributions of MNP in the biomaterial. The proposed data processing approach allows a quantitative characterization MagS, in terms of their (estimated) thickness and refractive index. Moreover, the proposed procedure allows to identify the areas of the scaffold wherein MNP are mainly concentrated and thus, it gives us information about MNP spatial distribution

A Portable Microwave Scanner for Brain Stroke Monitoring: Design, Implementation and Experimental Validation

This paper presents the design, the realization, and the experimental assessment of a novel portable microwave scanner prototype for brain stroke monitoring. The device employs a 22-antenna-array, placed conformal to the upper head part, composed of compact, flexible, and custom-made antennas working at around 1 GHz. The validation includes the monitoring of an experimentally emulated evolving hemorrhagic stroke. The progression of the medical condition is emulated via a non-static phantom (custom-shape balloon), derived from medical images, and a single-cavity 3-D anthropomorphic head phantom. The phantoms are filled with liquids mimicking the dielectric properties of the hemorrhage and the average brain tissues, respectively. The imaging-based follow-up is approached using a differential scheme that receives the scattering matrices, taken at two different instants, and exploits the distorted Born approximation to form the image in real-time. The kernel of the imaging algorithm is computed through accurate numerical models. The results verify the capabilities of the system to assess the continuous evolution of the stroke

Broadband Electromagnetic Sensing for Food Quality Control: A Preliminary Experimental Study

Quality control is of great importance in food industry, both for the evaluation of product characteristics and to avoid the occurrence of foreign bodies contamination in packaged items. With respect to the inspections against possible contaminants inside the product, different technologies are currently adopted along production chain lines. However, the number of accidents involving low density objects remains very large. To overcome this limitation, the use of electromagnetic technologies has been recently proposed. In this work, the synergic use of terahertz and microwaves technologies is proposed, so to provide high resolution images and in-depth inspections of different scenarios, including low density materials. A focus study on sugar samples is considered, reporting both its broadband characterization at microwaves and preliminary terahertz imaging to evaluate the integrity of the packaging. Ongoing research is devoted to the development and validation of a microwave device for monitoring food products along the production line

Innovative imaging tools and devices for clinical monitoring within the EMERALD network

The Marie Skłodowska-Curie Innovative Training Network EMERALD is a recently started project aimed at progressing the state of the art of microwave imaging devices for medical applications. In this framework, the goal of the project tasks based at CNR-IREA is twofold. First, ad-hoc imaging algorithms tailored to the prototype devices for clinical follow-up and image-guided treatment designed and realized within the network will be developed. Second, a microwave imaging device for monitoring and guiding microwave ablation treatments will be designed, realized and tested. This paper presents the initial research activities carried out by the CNR-IREA team within the EMERALD project

A compact slot-loaded antipodal vivaldi antenna for a microwave imaging system to monitor liver microwave thermal ablation

This study presents the design and the experimental validation of a slot-loaded antipodal Vivaldi antenna. The intended use is in an array configuration for monitoring liver microwave thermal ablation by way of microwave imaging (MWI). To optimize electromagnetic power transfer to the human abdomen, the antenna was designed to operate in a coupling medium. The final design has overall dimensions of 40 mm × 65 mm, and the working bandwidth goes from 600 MHz up to 3 GHz, with the possibility to operate at higher frequencies, also. The antenna proposed in this study shows the most compact aperture dimension, as compared with other antennas designed for biomedical applications, working within the same bandwidth. To experimentally evaluate the antenna performances, the coupling medium was realized, proposing a recipe made by low cost, and easy to provide and use, materials. In particular, a mixture of water, oil, dishwashing detergent, and guar gum was used. The realized material showed dielectric properties close to the target ones, proved stability on a 1-week time, and reproducibility against different realizations. The antenna's measured S-parameters well agreed with the simulation result. When locating two antennas in close proximity, as in the MWI array configuration, the results showed good performances towards mutual coupling

A Microwave Imaging System Prototype for Liver Ablation Monitoring: Design and Initial Experimental Validation

Liver cancer is one of the most deadly diseases worldwide with an increasing yearly fatality rate. Thermal ablation treatments are considered to be an effective alternative to conventional surgery, but the lack of an effective imaging modality to monitor the treatment prevents from a full exploitation of their therapeutic potential. As such, there is an increasing interest in developing alternative imaging modalities. In this framework, due to the fact that thermally treated tissue exhibits different dielectric properties as compared to untreated tissue, microwave imaging is a potential candidate, offering the possibility of performing the treatment monitoring task in a truly non-invasive way and by means of a portable and low cost apparatus. In this communication the prototype of a microwave imaging system to monitor thermal ablation of liver is presented together with its initial experimental validation. The observed results, although still preliminary, confirm the anticipated treatment monitoring capabilities of microwave imaging

A first experimental proof of liver ablation monitoring through a microwave imaging system

Thermal ablation treatments are considered to be an effective alternative to conventional surgery to fight liver cancers, but an effective treatment monitoring is needed for a full exploitation of their therapeutic potential. Since thermally treated tissue exhibits different dielectric properties as compared to untreated tissue, microwave imaging is a potential candidate. In this communication the prototype of a microwave imaging system to monitor thermal ablation of liver is presented together with its initial experimental validation

Preliminary Assessment of the Origin of Spurious Magnetic Effects in Magnetic Nanoparticle Enhanced Microwave Imaging

Magnetic nanoparticles enhanced microwave imaging has a great potential in breast cancer diagnosis. In fact, thanks to the non-magnetic nature of human issues, it would allow high specificity diagnosis already at early stages. To meet this goal, a crucial requirement is to design and built an imaging device free of spurious magnetic effects, which could hide the useful signal due to the magnetic nanoparticles targeted to the tumor or induce false positives. In particular, spurious effect -free measurements must be ensured up to the precision required to gather the very low useful signal. In this communication, we report the preliminary results on an investigation aimed to assess the origin of the possible spurious magnetic signals, in order to devise effective actions for their elimination