Impact: More precise technology for localising wireless capsule endoscopes in the GI tract

The wireless capsule endoscope (WCE) is a first-line medical tool for the diagnosis of many gastrointestinal tract diseases such as obscure GI bleeding, Crohn’s disease, small bowel tumours, and Celiac disease.

Currently a diagnostic-only tool, significant efforts are now focused on upgrading the WCE to an active medical ‘robot’ that has both diagnostic capabilities and therapeutic functionalities, such as biopsy, microsurgery and targeted drug delivery. However, a major limitation preventing the development of such a robotic-type endoscope is the lack of a highly accurate localisation system – until now.

A team lead by Professor Gursel Alici, Head of School of Mechanical, Materials and Mechatronic Engineering, and Leader of Soft Robotics for Prosthetic Devices Theme at the ARC Centre of Excellence for Electromaterials Science (ACES) has conceptualised and experimentally verified a new, real time localisation method for wireless capsule endoscopes.

With simulation and experimental results showing the best localisation data reported in literature so far, the system is based on tracking three positron emission markers embedded in the cover of an endoscopic capsule being moved automatically inside a water phantom, which mimics the photon attenuation of a human body.

Coincidence gamma rays emitted from the markers are sensed by surrounding gamma ray detectors. The position and orientation information of the capsule can then be extracted by an effective tracking algorithm.

Experiments undertaken by the team were conducted in two different commercial positron emission technology (PET) scanners. They showed the proposed localisation method could provide less than 0.5mm position error and 2.4◦ orientation error in a localisation time interval of 50 milliseconds with an average computational time of six milliseconds per time interval.

Zero power consumption and zero space occupation inside the capsule are additional advantages of this localisation method.

This breakthrough in the localisation of wireless medical devices within the human body has significant potential for improved patient outcomes, thanks to better diagnosis and more effective therapy. 

    Professor Gursel Alici
    Trung Duc Than
    Dr Steven Harvey