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Influence of patient head definition on induced E-fields during MR examination
(2024)Magnetic Resonance in MedicinePurpose Radiofrequency (RF) exposure during MR examination is limited by IEC 60601-2-33 to prevent thermal hazards to patients. These limits are also the basis to derive the maximum induced field for the demonstration of MR safety of implants per ISO/TS 10974 (2018). One limit is the head-averaged specific absorption rate (SAR), for which the head extent is defined differently by MR and implant vendors. The purpose of this technical note ...Journal Article -
A Personalized Pipeline for Modeling the Effects of Non-invasive Stimulation on Brain Network Dynamics
(2023)Neurological and psychiatric disorders represent an increasing challenge to the health of populations around the globe. In response, we have developed a personalized pipeline for modeling the effects of non-invasive electromagnetic (EM) stimulation on large-scale brain network activity. Personalization is integrated at three key stages of the pipeline: personalized anatomy, personalized connectivity, and personalized source-to-sensor ...Conference Poster -
Non-invasive temporal interference electrical stimulation of the human hippocampus
(2023)Nature NeuroscienceDeep brain stimulation (DBS) via implanted electrodes is used worldwide to treat patients with severe neurological and psychiatric disorders. However, its invasiveness precludes widespread clinical use and deployment in research. Temporal interference (TI) is a strategy for non-invasive steerable DBS using multiple kHz-range electric fields with a difference frequency within the range of neural activity. Here we report the validation of ...Journal Article -
A Pipeline for Personalized Brain Modeling: From Stimulation to Network Activity
(2023)BioEM 2023 - Abstract CollectionNeurological and psychiatric disorders are the leading cause of disability worldwide. Personalized computational modeling is a powerful method for probing whole brain network dynamics in both health and disease, and for creating optimized brain stimulation-based therapies. To this end, we developed an automated patient-specific modeling pipeline starting from structural magnetic resonance imaging (MRI) scans, and resulting in a 16 tissue, ...Other Conference Item -
Personalized Modeling for Investigating Electric Neuromodulation of Large Scale Brain Network Dynamics
(2023)Mental, neurological, and psychiatric disorders are a leading cause of death and disability worldwide. Personalized computational modelling for investigating large-scale brain network dynamics is a powerful method for optimizing non-invasive brain stimulation therapies. To this end, we developed an automated, personalized modeling pipeline on o2S2PARC, an open, cloud-based platform for creating, sharing, and publishing computational models ...Conference Poster -
Soft-x-ray confined-electron laser
(2023)Physical Review AA confined electron laser is a “wiggled” electron beam confined by the ponderomotive forces inside an electromagnetic cavity. The ponderomotive forces counteract the beam expansion due to space-charge forces, thereby enabling lasing at low energies. In this Letter we show the possibility of lasing at a wavelength of approximately 4 nm in the soft-x-ray regime. We simulate various cavity parameters and show that electron-beam confinement ...Journal Article -
Traceable Absorbed Power Density Assessment System in the 28 GHz Band
(2023)BioEM 2023 - Abstract CollectionICNIRP and IEEE closed a critical gap in the safety guidelines by introducing a basic dosimetric restriction above 6 GHz. These are the absorbed power density (APD) and the spatial averaged power density. In previous work by our group, a phantom and a compatible probe were developed to measure the APD in the 5G new radio frequency range 2 (NR FR2; 24–30 GHz). Here, an experimental validation procedure for the proposed phantom is detailed. ...Other Conference Item -
Noninvasive measurement of head dielectric properties as a novel method for monitoring intracranial volume variations
(2023)Journal of Affective Disorders ReportsOther Conference Item -
The effect of body position change on noninvasively acquired intracranial pulse waves
(2023)Physiological MeasurementObjective. Craniospinal compliance (CC) is an important metric for the characterization of space-occupying neurological pathologies. CC is obtained using invasive procedures that carry risks for the patients. Therefore, noninvasive methods for acquiring surrogates of CC have been proposed, most recently based on changes in the head’s dielectric properties during the cardiac cycle. Here, we have tested whether changes in body position, ...Journal Article -
Coverage factors for efficient demonstration of compliance of low-frequency magnetic near-field exposures with basic restrictions
(2023)Physics in Medicine and BiologyObjective. Regulators require that wireless power transfer (WPT) systems and other strong magnetic field sources are compliant with the basic restrictions (BR) defined as the limits of the fields induced in the human body, i.e. the induced electric field/current density/specific absorption rate limits. This can be achieved by demonstrating compliance with the reference levels (RL) defined in air without the human body, i.e. the incident ...Journal Article