Biotelemetry permits the measurement of physiological signals at a distance, with its latest application being in the field of implantable and ingestible medical devices (IIMDs) (Fig. 1). Implantable MDs perform an expanding variety of diagnostic/therapeutic functions, while ingestible MDs receive significant attention in wireless endoscopy. In the past, wireless biotelemetry relied on inductive coil coupling. To overcome the inherent drawbacks of low data rate, restricted communication range, and sensitivity to coils’ positioning, research is nowadays oriented towards antenna-enabled biotelemetry. Design of such IIMD biotelemetric systems attracts high scientific interest to deal with the challenges of operation frequency selection, electronic circuit and antenna design, link performance, patient safety and biotelemetry-telemedicine-integration.

Fig. 1: Body Are Networks & Biotelemetry.

A novel Design-and-Evaluation closed-loop Methodology for biotelemetry-telemedicine-integrated systems of antenna-enabled IIMDs (DEMIIMD) is proposed (Fig. 2) - STEP 1: Design the data/power IIMD electronics (evaluate in terms of power consumption, complexity, size, cost); STEP 2: Design the application-specific IIMD-antenna with emphasis on miniaturization, by employing techniques such as ground pins, high dielectric materials, patch-stacking, and conductor meandering/spiraling (evaluate in terms of resonance characteristics and radiation performance [radiation pattern, gain, radiation efficiency]); STEP 3: Add an exterior MD to form the biotelemetry link (evaluate in terms of transmission coefficient, power received, communication range, required receiver sensitivity, protocols/standards, data/bit error rates, interference); STEP 4: Determine the electromagnetic (EM) exposure scenario (single-/multi- exposure), and perform a thorough study on safety issues; STEP 5: Design the telemedicine link (evaluate in terms of protocols/standards, data/bit error rates, interference); STEP 6: Evaluate system performance (in terms of all aforementioned criteria), and perform design improvements.

Fig. 2: Block diagram of the proposed DEMIIMD.

The project comprises six workpackages (WPs). [WP1]-[WP5] address issues raised within the first five steps of the DEMIIMD, respectively. Research emphasis will be on the IIMD-antenna [WP2], biotelemetry link [WP3], and safety [WP4], while electronics [WP1] and telemedicine-integration [WP5] issues will also be addressed. [WP6] validates the DEMIIMD within a novel system for wireless ICP monitoring.
1. [WP1] IIMD Electronics: Data and Powering circuits (simulations)
2. [WP2] Novel IIMD-Antennas (simulations and experiments)
3. [WP3] IIMD Biotelemetry Link (simulations and experiments)
4. [WP4] Safety issues (simulations and experiments)
5. [WP5] IIMD Biotelemetry-and-Telemedicine Integration (simulations)
6. [WP6] DEMIIMD Validation (simulations + experiments)

The motivation is that most studies for MDs are limited to design and safety issues of external sources, although more and more IIMDs are clinically employed. Uniqueness mainly lies in the proposal of the DEMIIMD, as a standardized procedure which addresses interconnecting interdisciplinary challenges to design and evaluate optimized biotelemetry-telemedicine-integrated systems for IIMDs. Contribution of this research is complemented by extensive simulations and in-vitro/in-vivo tests to provide significant progress beyond the state of the art, with the highlights being: optimized design algorithms for miniature IIMD- antennas, reliable antenna testing, thermal/multi-source/in-vitro dosimetry for IIMDs, novel methods to assess tissue temperature rise, in- and out-of-body channel modeling and biotelemetry-telemedicine-integration.

Project abbreviation: DEM-II-MED
Project full title: Implantable and Ingestible Medical Devices (IIMDs): Optimal-Performance-Oriented Design and Evaluation Methodology
Funding: The project is co-funded by the European Union (European Social Fund - ESF) and by national funds from the Operational Programm "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) 2007-2013. Action: «ARISTEIA»
Duration: 36 months – 2012-2015
Project reference: ARISTEIA 1777