An innovative UWB Real-Time Position Tracking System proposal, for a Cardiological IVUS catheter D. Fotiadis, A. Astaras, P. Bamidis, K. Papathanasiou, A. Kalfas Aristotle University of Thessaloniki, School of Medicine, Laboratory of Medical Informatics, Thessaloniki, Greece [dfotiadis, astaras, bamidis]@med.auth.gr, kostasp@physics.auth.gr, akalfas@auth.gr http://lomiweb.med.auth.gr Abstract Precise determination of the position of a medical device inside the human body, specifically the tip of an Intravascular Ultrasound (IVUS) catheter, is a process currently relying primarily on angiography techniques. The injection of a radio-opaque contrast agent into the bloodstream and subsequent use of contrast-enhanced X- ray imaging is still the most common technique used by medical staff to track the exact position of the IVUS catheter inside the human body. This position tracking methodology has numerous shortcomings and imposes unnecessary risks on the patient, as compared to a new technology and associated methodology proposed in this paper. In the first part, a position tracking technology survey is presented, followed by the details of the proposed Ultra Wideband (UWB) methodology, a discussion of its advantages and disadvantages, as well as the definition of a development roadmap. Keywords: IVUS, UWB, SoC integration, Position Tracking, Precision Ranging. 1. Introduction Position tracking is a technology with a considerable historical record and number of associated researchers in science and engineering. Some of the applications fields that commonly employ and benefit from position tracking are biomedical engineering, military applications, robotics, the animation industry and virtual reality. Each sector imposes particular requirements and design specifications on position tracking systems, thus tracking implementations vary significantly across them. The overall size of the system, its precision, operational range, cost, or even public health issues, are among the factors that promote one technology over another. Biomedical engineering applications and Intravascular Ultrasound (IVUS) scanning in particular impose stringent technological limitations to all aforementioned system aspects. Additional critical parameters in real-time intravascular position tracking scenarios are the absence of direct Line-of-Sight (LOS) between the IVUS catheter and the external tracking system, as well as limited room for wiring due to the small catheter cross-section area (typically ≤0.5mm). IVUS scanning is an imaging methodology that provides medical staff with information regarding intravascular morphology, the ultimate aim commonly being to assess atheromatic plaque accumulation in coronary circulation. Angiography and contrast-enhanced X-ray imaging are commonly employed in order to track the distal end of the IVUS catheter [1], despite clear disadvantages regarding time, cost and ionized radiation safety concerns for both the patient and the medical staff in the operating room. There is clearly room for improvement, therefore a new real-time position tracking methodology is proposed in this paper. Position tracking techniques based on electromagnetic RF (radio frequency) methods have been invented, implemented and improved for several decades now. Some of these methods can be adapted for use along with IVUS scanning, while several others would be sub- optimal or entirely inappropriate technological choices. These methods will be mentioned succinctly in the following section, while the advantages of ultra wideband (UWB) technology will serve as the focus for a more detailed subsequent discussion. An important evaluation parameter in biomedical engineering and more specifically in IVUS scanning is the seamless integration of introduced technologies to existing surgical routines. The added functionality of precisely determining the IVUS catheter tip position in real time means that the catheter has to be specially modified in order to contain a tracking element or “tracker”. This tracking element will provide position information for the catheter tip in a cartesian or polar coordinate system, relative to a reference point determined during an earlier calibration phase. Χ-ray imaging or angiography methods may need to be applied prior to the catheter position tracking initialization, in order to obtain the reference point’s coordinates. In the next Section the position determination and BIME Journal, Volume 12, Issue 1, December 2012 7