Plenary Sessions

Plenary 1: EM exposure risks for persons with implants: A neglected population?

Session: P1
Monday, June 20, 2022 • 09:00 – 10:00, Large Hall

Niels Kuster (TH Zurich & IT’IS Foundation, Zurich, Switzerland)
Aiping Yao (School of Information Science and Engineering, Lanzhou University, Lanzhou, China)

Summary

The number of patients implanted with medical devices has constantly and rapidly grown and now comprises several million patients worldwide. The current safety guidelines and national regulations for electromagnetic exposures do not consider the potential additional risks due to the presence of conductive implants. The objective of this plenary is to summarize the state of the art in this area, and to identify present research gaps and regulatory shortcomings.The first part of plenary will discuss the mechanism of local enhancements of induced fields as a function of frequency and implant size, and review the conditions under which these enhancements can pose additional health risks.In the second part, we illustrate how these risks are evaluated and mitigated in the special case of magnetic resonance (MR) examination, through a set of approaches with tunable complexity and conservativeness which can be extended to regulation of other exposure scenarios.

Rationale

The risks posed to persons with implants have been largely ignored and will likely become a growing concern due to rapidly increasing number of people with implants being exposed to strong low frequency fields, such as wireless power transfer systems. The topic is of interest to regulators, engineers, and experts involved in exposure assessment and risk analysis.

Plenary 2: What about 5G? – Biological effects of millimetre waves – research base, safety standards, and knowledge gaps

Session: P2
Tuesday June 21, 2022 • 08:30 – 09:30, Large Hall

Myrtill Simko (SciProof International AB, Östersund, Sweden)

Radio waves in the frequency band from 30 to 300 GHz (wavelengths from ten to one millimetre) in the electromagnetic spectrum belong to the millimetre waves (MMW). These waves have a short range in the Earths ́ atmosphere and attenuate fast due to the gaseous atmosphere. Thus, they can only be used for short range terrestrial communication but will nevertheless play a role in the 5G-based mobile communication technology (FR2) which presently is rolled out globally.
Compared to frequencies presently used for mobile communication, studies that specifically focus on biological and health-related effects of MMW are more sparse but are presently initiated in higher numbers. This lecture will provide and overview of available research findings, primarily from in vivo animal studies and in vitro studies, based on a recent review article (Simkó and Mattsson [1]) and additional recent studies. Furthermore, the presentation will cover risk assessment aspects and relevant safety standards such as ICNIRP and IEEE. Finally, identified knowledge gaps relevant for safety considerations will be addressed.

Plenary 3: Transient changes in membrane hydration of liposome exposed to nanosecond electric pulses detected by wide-field Coherent anti-Stokes Raman microspectroscopy

Session: P3
Thursday June 23, 2022 • 08:30 – 09:30, Large Hall

Caterina Merla (ENEA National Italian Agency for Energy and New Technologies, Italy)
Luis Mir (Université Paris-Saclay, France)

To deep more insight into basic phenomena occurring during and after electropulsation of biological membranes, a new experimental modality has been used combining a wide field Coherent Anti Stokes Raman Spectroscopy system [1] with a coplanar wave guide able to deliver nanosecond pulsed electric fields to different in vitro samples [2]. This setup allows to acquire i) CARS hyper-spectra at specific Raman bands from 2900 to 3500 cm-1 (into the so-called water vibration region) as well as ii) to acquire in real time the CARS signature at specific wavelengths with a temporal resolution of few ns. This time scale is comparable to the duration of the electrical stimulation synchronised to the laser emission. As the biophysical and chemical bases of cells electropulsation are still debated, our setup allows the experimental assessment of the role of water molecules and phospholipid bilayers during and after the occurrence of this phenomenon, which is used in various biotechnological, biological and medical applications.
Our experiments have been conducted on liposome suspensions placed between the central and lateral (ground) electrodes a grounded closed coplanar waveguide (GCCPW) [2], assuring the transmission of short electric pulses (10 ns) to the biological samples without distortions. Liposomes, that is lipid spherical unilamellar vesicles, where chosen as a suitable synthetic system to mimic phospholipid double layers as they are similar to the structure of real cell membranes. The illumination scheme of the CARS microscope followed a non-phase-matched geometry as suggested in [1] especially useful for transparent samples and for fast CARS signal acquisitions. Spectra of liposomes suspensions were acquired immediately after electropulsation. These experiments demonstrated a significant increase of the vibrational modes around 3345 cm-1 in the pulsed samples with respect to the non-pulsed ones. The increase of this vibrational signature (3345 cm-1), at a higher Raman shift than the vibrational signature (3145 cm-1) of the symmetric OH stretch modes of the surface water (like the bulk or the interfacial water), reflects an increased presence of water molecules located inside the membrane. Indeed, the intermolecular OH bonds of the so-called lipid associated water molecules are weaker because they reflect asymmetric OH stretch modes, imposed to the water molecules by the vicinity with the lipids [3, 4]. This association makes the pulsed membrane more permeable due to this less organized and persistent structure of the water molecules. The appearance of this vibrational mode has been also verified during the exposure, in real-time specific experiments.
Finally, the effective permeabilization of liposome suspensions after the electric pulses delivery was verified looking at the release of a fluorescent dye (5-6-carboxyfluorescein) preloaded into the liposomes core. Dynamic light scattering measurements (performed before and after the electric pulses exposure) demonstrated the maintenance of the vesicles integrity supporting the permanent hydration of the liposome membranes after electropulsation.
The observed pulse-dependent accumulation of interstitial water molecules in the membranes was theoretically described and a plausible mechanism supported by a computational electrochemical model is discussed.
In summary, CARS, employing nanosecond lasers pulses and the properties of our wide field microscope and its intrinsic ability to sense complex interferences, has provided us with an appropriate diagnostic tool. In a future, the underlined mechanism will be investigated on cells, hence taking into account recovery processes of cell membranes as well as the different interactions elicited by the application of longer ms electric pulses.

Plenary 4: The MOBI-Kids study: association between wireless phone use in childhood and adolescence and brain tumours

Session: P4
Friday June 24, 2022 • 08:30 – 09:30, Large Hall

Elisabeth Cardis (Gemma Castaño-Vinyals & the MOBI-Kids Study Group, Spain)

This presentation will focus on the methods and results of the MOBI-Kids study, a multinational case-control study of brain tumours in young people designed to evaluate whether RF and ELF from wireless phone use may affect the risk of brain tumours. The study provides no evidence of a causal association between wireless phone use and brain tumours in young people.