oa Navigation capabilities for a flexible tethered capsule endoscope

Introduction: Stomach cancer is one of the leading causes of death. The two main existing screening tests are the non-invasive carbon urea breath test (not reliable enough) and the classical gastric endoscopy (costly and uncomfortable) which is preferred by clinicians. However, patients are reluctant to do it and this increases the chance to detect stomach cancer after the early stage of development. To overcome these limitations, an efficient "patient oriented" and clinically efficient approach to stomach cancer detection is highly relevant. The most famous autonomous capsule is probably PillCam, the first commercialized and FDA approved capsule endoscope. It is equipped with a video camera but has no navigation abilities. Its two main limitations compared to the classical endoscopes are the lack of control and the impossibility to perform a biopsy. In this abstract, a new approach for early stomach cancer detection is proposed: a tethered capsule endoscope containing embedded visual sensing (Seibel et al., 2008, IEEE Transactions on Biomedical Engineering), chemical sensing (Arnecke et al., 2009, Analytical Chemistry) and offering navigation abilities. Preliminary design: The tethered capsule endoscope comes as an interesting alternative. Being tethered, there is no need to embed the energy source and electronics required for navigation and sensing. This enables a great simplification of the embedded material and thus a cost reduction of the capsule itself. This also allows a drastic size reduction and ensures a great sense of comfort during the whole procedure. Moreover, using a chemical sensor embedded in the capsule design gives the possibility to perform an improved in situ version of the carbon urea breath test. The navigation system is based on the actuation of the last portion of the tether. It can bend in all direction up to 180° thus allowing orienting the sensors toward every desired portion of the stomach (Figure 1). The capsule contains a wire pulling system. Controlling in opposite pairs the pull and release of the wires allows producing bending motions of the tether active portion. The wire pulling system uses two miniature piezoelectric linear motors coupled with two extension springs. One nylon wire is attached to each linear motor and each opposite wire is attached to an extension spring (Figure 2). The actual prototype for navigation along with micro optochemical sensor set is currently under fabrication. This work was made possible by the support of an NPRP grant from the Qatar National Research Fund (NPRP4-049-2-021). The statements made herein are solely the responsibility of the authors.