Localization and tracking of robotic endoscopic capsules using multiple positron emission markers

Wireless capsule endoscope (WCE) is a first-line medical tool for the diagnosis of many gastrointestinal (GI) tract diseases such as obscure gastrointestinal bleeding, Crohn’s disease, small bowel tumors, and Celiac disease. In the past few years, significant research attention has been dedicated to upgrading the WCE from a diagnostic-only tool to an active medical robot having not only diagnostic capabil- ities but also therapeutic functionalities such as biopsy, microsurgery, and targeted drug delivery. One of the major limitations that impedes the development of such a robotic-type endoscope is the lack of a highly accurate localization system. In this thesis, a novel localization method based on tracking multiple positron emis- sion markers is presented. In the method, three spherical markers with diameters of less than 1 mm are embedded in the cover of an endoscopic capsule. Two pairs of gamma ray detector modules are arranged around a patient’s body to detect co- incidence gamma rays emitted from the three markers. The positions of the three markers, which refer to the position and orientation of the capsule, can then be determined using an effective tracking algorithm. The algorithm consists of four consecutive steps: a method to remove corrupted data, an initialization method, a clustering method based on the Fuzzy C-means clustering algorithm, and a failure prediction method.