Wireless medical telemetry: Current status and future directions

Abstract

Summary form only given. Wireless telemetry is the remote monitoring of patients' physiological parameters (e.g., cardiac signals, blood glucose, body temperature) over a distance via radiofrequency (RF) communications between a transmitter worn by the patient and a central monitoring station. Undoubtedly, this technology delivers mobility, comfort, and higher levels of patient care. As designers develop new implanted medical devices taking advantage of RF technology to improve the quality of care for patients, antennas are key to these new systems. Although the antennas and RF system design is well understood for today's telecommunication systems, their application in medical systems offer unique challenges. One of the main issues is power consumption, for the in-body monitoring systems for instance, the antenna used for the implantable device should be able to radiate outside the body and yet the power associated with the device must comply with the radiation requirements. Increased power levels might cause heating of the tissue and consequently a permanent tissue damage. Moreover, it is important to design the antenna with a minimum interference with other electronic devices inside or outside the body and must be composed of biocompatible materials and must be very small to minimize the reaction of the surrounding tissues to the implant. Such restrictions demand for implantable antennas that are small in size. There are several ways to miniaturize implantable antennas. One way is to optimize the topology of the antenna and the other way is to optimize the dielectric materials used in the design. Recently, topology optimization has been carried out combining Finite- Element Boundary-Integral algorithm with particle swarm optimization for designing a dual band implantable antenna. This study has led to the design of a small antennas operating at medical implant communications services (MICS) (402 MHz-405 MHz) / MedRadio (401 MHz-406 MHz) and industrial, scientific and medical (ISM) 433 MHz and (2.4 GHz-2.48 GHz) bands. We have designed several miniature implantable antennas for these frequencies.In this talk, design and fabrication details of implantable antennas will be discussed and the results regarding in-vitro hydrogel and animal (rats and porcine) studies are presented. The talk will also include a detailed discussion of current status of the wireless medical telemetry device development around the globe and some discussion on what lies ahead.