Michael Oberle

The Virtual Family—development of surface-based anatomical models of two adults and two children for dosimetric simulations

The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community.

An Attempt to Model the Human Body as a Communication Channel

Using the human body as a transmission medium for electrical signals offers novel data communication in biomedical monitoring systems. In this paper, galvanic coupling is presented as a promising approach for wireless intra-body communication between on-body sensors. The human body is characterized as a transmission medium for electrical current by means of numerical simulations and measurements. Properties of dedicated tissue layers and geometrical body variations are investigated, and different electrodes are compared. The new intra-body communication technology has shown its feasibility in clinical trials. Excellent transmission was achieved between locations on the thorax with a typical signal-to-noise ratio (SNR) of 20 dB while the attenuation increased along the extremities.

Signal Transmission by Galvanic Coupling Through the Human Body

Galvanic coupling is a promising approach for wireless intrabody data transmission between sensors. Using the human body as a transmission medium for electrical signals becomes a novel data communication technique in biomedical monitoring systems. In this paper, special attention is given to the coupling of the current into the human body. Safety requirements have to be fulfilled, and optimal signal coupling is of essence. Therefore, different electrodes are compared. A test system offers up to 1 mA contact current modulated in the frequency range of 10 kHz to 1 MHz. The injected current is up to 20 times below the maximum allowed contact current. Such a low-current approach enables data communication that is more energy saving than other wireless technologies.

Galvanic Coupling Enabling Wireless Implant Communications

Galvanic coupling has been shown to be the best method for low-power on-body data transmission. This approach has been extended toward wireless communication between implanted devices, building a real intrabody sensor network. To show the feasibility, a test system has been developed and implemented. The measurements are compared with the numerical simulations. The prototype offers four concurrent channels with a throughput of 4.8 kb/s. The main focus is the future implantability of such a miniaturized system for the medical long-term surveillance of patients. To achieve this goal, small circuit size, low power consumption, and electrical safety have to carefully be considered.

Measurement System for the Characterization of the Human Body as a Communication Channel at Low Frequency

Electronic data transfer by capacitive and galvanic coupling through the human body has been proposed by research and industry as a novel but highly promising technology for ultra low power wireless body LANs. Investigation on the most challenging questions considering data communication becomes enabled with a highly versatile measurement system for frequencies in the range of 10kHz to 1MHz. The human body is characterized as a transmission medium for electrical current by means of measurements and is investigated as communication channel for biomedical parameter monitoring by using different modulation schemes at low frequency. Excellent transmission was achieved on the thorax while the attenuation increases along the extremities. The injected current is 10 times below the maximum allowed contact current and more than 25 times below nerve stimulation. The new technology has shown its feasibility in clinical trials

From Dielectrical Properties of Human Tissue to Intra-Body Communications

Novel wireless communication networks for body mounted sensors explore the use of human tissue as a transmission medium. Electrical signal propagation through the human body requires a deep understanding of the dielectrical properties of human tissue. In this work, the dielectrical properties have been investigated to determine the pathway of current flow through the body with respect to data communication between body mounted sensors. Digital data communication by galvanic coupling in the frequency range up to 1 MHz is presented as a promising approach for wireless intrabody communication.

BPSK & QPSK Modulated Data Communication for Biomedical Monitoring Sensor Network

Data communication between body-mounted sensors is progressing towards wireless monitoring networks. In this work, digital data communication by galvanic coupling through the body is presented as a promising approach for wireless intra-body communication. The human body itself serves as the transmission medium of electrical current. Both binary and quadrature phase-shift-keying (BPSK and QPSK) modulated data transmissions are implemented and compared for galvanic coupled links between 2 differential electrode pairs. The adaptive system offers up to 1 mA maximum current amplitude between 10 kHz and 1MHz. Data communication at a rate of up to 64 kbit/s was realized with BER of 10 -4 corresponding to an SNR greater than 6 dB. The novel technology has shown its feasibility in clinical trials. Furthermore, such a low-current approach enables data communication that is more energy-saving than other wireless technologies

Investigation on Coupling Strategies for Wireless Implant Communications

Monitoring of human vital functions is enabled by wireless technologies for distributed on-body mounted monitoring sensors. Galvanic coupling provides a novel data communication between sensors with coupling electrodes attached to the human skin. The next step is an implantable communication device. This study focuses on coupling strategies for intra-body communication between implantable miniaturized transceiver pills.

Digital Data Communication through the Human Body for Biomedical Monitoring Sensor

Data communication between body mounted sensors is progressing towards wireless monitoring networks. In this work, digital data communication by galvanic coupling through the body is presented as a promising approach for wireless intra-body communication.