Telemetry capsule for measuring contractile motion in the small intestine

Modelling on mutual inductance of wireless power transfer for capsule endoscopy

Wireless capsule endoscopy (WCE) is noninvasive, painless, and riskless on detection for gastrointestinal disease. It attracts increasing attention. Wireless power transfer (WPT) technology is utilized to supply power for WCE. Receiving coil (RC) of WPT is capsulated into WCE. Its position and direction change all through gastrointestinal tract. Transmitting coil (TC) is worn by the patient. So the mutual inductance varies all the time. It should be studied to ensure sufficient receiving power. However, existing analytical methods do not reach satisfactory accuracy. They can only solve simple cases with positional misalignment. Numerical simulation models are time-consuming. Furthermore, an entirely new simulation must be repeated when any change in alignment occurs. Thus, based on geometry and misalignment of RC and TC, a model for mutual inductance is proposed. Compared with analytical methods, it is applicable to not only circular and rectangular RC, but also the elliptic, with directional misalignment. It costs below 0.1% of computational time of the simulation for the same accuracy. Moreover, any change in misalignment is easily handled by a simple change of parameter in the model. It reaches a tradeoff between computational accuracy and time. Receiving power is evaluated rapidly and accurately with proposed model.

Design of a Wireless Medical Capsule for Measuring the Contact Pressure Between a Capsule and the Small Intestine

A wireless medical capsule for measuring the contact pressure between a mobile capsule and the small intestine lumen was developed. Two pressure sensors were used to measure and differentiate the contact pressure and the small intestine intraluminal pressure. After in vitro tests of the capsule, it was surgically placed and tested in the proximal small intestine of a pig model. The capsule successfully gathered and transmitted the pressure data to a receiver outside the body. The measured pressure signals in the animal test were analyzed in the time and frequency domains, and a mathematic model was presented to describe the different factors influencing the contact pressure. A novel signal processing method was applied to isolate the contraction information from the contact pressure. The result shows that the measured contact pressure was 1.08 ± 0.08 kPa, and the small intestine contraction pressure's amplitude and rate were 0.29 ± 0.046 kPa and 12 min−1. Moreover, the amplitudes and rates of pressure from respiration and heartbeat were also estimated. The successful preliminary evaluation of this capsule implies that it could be used in further systematic investigation of small intestine contact pressure on a mobile capsule-shaped bolus.

A Review of Locomotion Systems for Capsule Endoscopy

Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties.