Electromagnetics for Medical Applications
Assoc. Prof. Mariana Dalarsson leads the Electromagnetics for Medical Applications research group at KTH. The group investigates novel medical treatments and technologies based on electromagnetic (EM) waves, with a particular focus on developing non-invasive approaches to diagnostics and therapy.
Gold Nanoparticles
One area of research within the group is on the use of gold nanoparticles (GNPs) to enhance EM-based medical treatments. Due to their favourable EM properties when embedded in biological tissue, GNPs have been proposed for a wide range of biomedical applications. When exposed to EM radiation, the GNPs can produce localized field enhancement within the nanoparticle and in its immediate surroundings. This phenomenon can be exploited for applications such as contrast enhancement in medical imaging, localized energy deposition for non-invasive radio frequency cancer hyperthermia, and non-invasive deep brain stimulation.
Compared to optical frequencies, the longer wavelengths associated with RF radiation provide greater penetration into biological tissue, making RF-based approaches potentially suitable for targeting deeper regions of the body. Current research aims to improve the understanding of the physical mechanisms underlying RF energy absorption and heating in GNPs. This includes developing detailed electromagnetic models of ligand-coated GNPs to quantify the influence of surface ligands on energy absorption, as well as investigating multiple-particle interactions and the resulting heating effects.
Non-Invasive Deep Brain Stimulation
Another major research area within the group is on non-invasive deep brain stimulation (DBS), closely connected to our most recent project awarded by the Swedish Research Council (VR). The project builds on the principle underlying conventional DBS, namely that EM fields can modulate neuronal activity to produce therapeutic effects.
Whereas current DBS therapies rely on invasive implantation of electrodes, our goal is to achieve similar stimulation effects non-invasively using microwaves (MWs). This has the potential to contribute to the treatment of neurological disorders including Parkinson’s disease, epilepsy, and depression.
Our approach uses external antenna arrays to generate focused MW fields within the brain. By controlling the configuration and excitation of the antenna array, the location and focal point can be moved or changed in size. We combine MW focusing techniques for spatial targeting with temporal interference (TI) for neuronal stimulation, with the long-term goal of developing a fully external, antenna-based DBS system.
Predicting MW propagation in the brain is challenging because biological tissues are lossy and dispersive, while the complex, multilayered structure of the head gives rise to internal reflections, transmissions, and strong spatial variations in the EM field. To address these challenges, the group investigates realistic brain modelling, antenna-array optimization, and treatment safety through the assessment of specific absorption rate (SAR) and tissue heating.
In parallel, we study how EM field distributions and their spatial and temporal properties can be shaped and optimized in relation to the structure and behavior of neurons, with the aim of improving stimulation selectivity and treatment efficiency.
Metasurface Arrays for Cancer Hyperthermia
Another recent research project within the group concerns AI-driven design of metasurface arrays for non-invasive cancer hyperthermia. Current EM hyperthermia systems face challenges in achieving precise targeting and sufficiently uniform heating, which limits their therapeutic effectiveness. This project aims to bridge the gap between promising metamaterial concepts and clinical requirements by developing AI-controlled metasurface arrays capable of adapting to patient-specific anatomy and tumor characteristics.
Related research in Electromagnetics in Medicine
The group also explores how concepts developed within these research directions may be combined, as concepts developed in one area may open new possibilities in another! In particular, the localized EM field enhancement associated with GNPs could potentially be exploited to improve the efficiency and selectivity of non-invasive DBS techniques. This represents part of a longer-term vision of connecting our research on GNPs, EM field focusing, and medical applications.
Last but not least, the group also works on electromagnetics for medical applications beyond these core research directions. This includes the development, optimization, and testing of antennas designed to operate within the human body, for example for biotelemetry, as well as antennas and EM systems for microwave-based medical imaging.
If you are interested in any of the above research areas, don't hesitate to contact any member of our research group below:
Members
