Technology of swallowable capsule for medical applications

Medical technology has undergone major breakthroughs in recent years, especially in the area of the examination tools for diagnostic purposes. This paper reviews the swallowable capsule technology in the examination of the gastrointestinal system for various diseases. The wireless camera pill has created a more advanced method than many traditional examination methods for the diagnosis of gastrointestinal diseases such as gastroscopy by the use of an endoscope. After years of great innovation, commercial swallowable pills have been produced and applied in clinical practice. These smart pills can cover the examination of the gastrointestinal system and not only provide to the physicians a lot more useful data that is not available from the traditional methods, but also eliminates the use of the painful endoscopy procedure. In this paper, the key state-of-the-art technologies in the existing Wireless Capsule Endoscopy (WCE) systems are fully reported and the recent research progresses related to these technologies are reviewed. The paper ends by further discussion on the current technical bottlenecks and future research in this area

Wireless capsule gastrointestinal endoscopy: direction of arrival estimation based localization survey

One of the significant challenges in Capsule Endoscopy (CE) is to precisely determine the pathologies location. The localization process is primarily estimated using the received signal strength from sensors in the capsule system through its movement in the gastrointestinal (GI) tract. Consequently, the wireless capsule endoscope (WCE) system requires improvement to handle the lack of the capsule instantaneous localization information and to solve the relatively low transmission data rate challenges. Furthermore, the association between the capsule’s transmitter position, capsule location, signal reduction and the capsule direction should be assessed. These measurements deliver significant information for the instantaneous capsule localization systems based on TOA (time of arrival) approach, PDOA (phase difference of arrival), RSS (received signal strength), electromagnetic, DOA (direction of arrival) and video tracking approaches are developed to locate the WCE precisely. The current article introduces the acquisition concept of the GI medical images using the endoscopy with a comprehensive description of the endoscopy system components. Capsule localization and tracking are considered to be the most important features of the WCE system, thus the current article emphasizes the most common localization systems generally, highlighting the DOA-based localization systems and discusses the required significant research challenges to be addressed

Frontiers of robotic endoscopic capsules: a review

Digestive diseases are a major burden for society and healthcare systems, and with an aging population, the importance of their effective management will become critical. Healthcare systems worldwide already struggle to insure quality and affordability of healthcare delivery and this will be a significant challenge in the midterm future. Wireless capsule endoscopy (WCE), introduced in 2000 by Given Imaging Ltd., is an example of disruptive technology and represents an attractive alternative to traditional diagnostic techniques. WCE overcomes conventional endoscopy enabling inspection of the digestive system without discomfort or the need for sedation. Thus, it has the advantage of encouraging patients to undergo gastrointestinal (GI) tract examinations and of facilitating mass screening programmes. With the integration of further capabilities based on microrobotics, e.g. active locomotion and embedded therapeutic modules, WCE could become the key-technology for GI diagnosis and treatment. This review presents a research update on WCE and describes the state-of-the-art of current endoscopic devices with a focus on research-oriented robotic capsule endoscopes enabled by microsystem technologies. The article also presents a visionary perspective on WCE potential for screening, diagnostic and therapeutic endoscopic procedures

On Simultaneous Localization and Mapping inside the Human Body (Body-SLAM)

Wireless capsule endoscopy (WCE) offers a patient-friendly, non-invasive and painless investigation of the entire small intestine, where other conventional wired endoscopic instruments can barely reach. As a critical component of the capsule endoscopic examination, physicians need to know the precise position of the endoscopic capsule in order to identify the position of intestinal disease after it is detected by the video source. To define the position of the endoscopic capsule, we need to have a map of inside the human body. However, since the shape of the small intestine is extremely complex and the RF signal propagates differently in the non-homogeneous body tissues, accurate mapping and localization inside small intestine is very challenging. In this dissertation, we present an in-body simultaneous localization and mapping technique (Body-SLAM) to enhance the positioning accuracy of the WCE inside the small intestine and reconstruct the trajectory the capsule has traveled. In this way, the positions of the intestinal diseases can be accurately located on the map of inside human body, therefore, facilitates the following up therapeutic operations. The proposed approach takes advantage of data fusion from two sources that come with the WCE: image sequences captured by the WCE\u27s embedded camera and the RF signal emitted by the capsule. This approach estimates the speed and orientation of the endoscopic capsule by analyzing displacements of feature points between consecutive images. Then, it integrates this motion information with the RF measurements by employing a Kalman filter to smooth the localization results and generate the route that the WCE has traveled. The performance of the proposed motion tracking algorithm is validated using empirical data from the patients and this motion model is later imported into a virtual testbed to test the performance of the alternative Body-SLAM algorithms. Experimental results show that the proposed Body-SLAM technique is able to provide accurate tracking of the WCE with average error of less than 2.3cm

Determining the Position and Orientation of In-body Medical Instruments Using Reactive Magnetic Field Mapping

There has been a huge demand for localizing in-body medical instruments (IBMI), such as wireless capsule endoscope (WCE) and nasogastric tube (NGT). Some stud ies have been conducted to solve this issue over the last three decades. In these studies, they either used a permanent magnet (PM), a static current source (SCS), radio frequency (RF) fields or integration of two of these. The PM is a stable and reliable magnetic field source. However, due to the size restriction of the NGT and the WCE, only a small PM can be used. Subsequently, the small size issue causes low power delivery at the larger tracking distance. Also, the PM field is very susceptible to ambient noise, and the PM-based localization is not possible in ap plications requiring robotic actuation. Even though an SCS can be used to replace the permanent magnet, and thus the current level can be varied in relation to the dis tance for optimized power delivery, it requires a relatively high power to generate a higher strength magnetic field. Consequently, a more powerful and larger battery is needed to feed the circuit.Radio frequency field sources require high frequencies to achieve sufficient precision, but these frequencies undergo high attenuation in the body. Therefore, the low-frequency RF field is preferred 1 . In the near-field 2 , plane wave assumption of the far-field fails for localization methods since the waves in this region are spherical. Hence, the wave-front has to be formulated by both the range and the direction of arrival (DOA). The DOA requires the phase difference of neighbouring sensors to be calculated. However, if the operating wavelength is much larger than the distance between the source and the receiver, it is not feasible to compute the phase difference between the neigh bouring sensors. Thus, there are numerous algorithms in the literature to overcome these issues, such as MUSIC or ESPRIT which are either complicated or computa tionally expensive. In RF-based localization, generally the time of arrival (TA), the time differ ence of arrival (TDA), the angle of arrival (AOA) and the received signal strength (RSS) are widely used for localization. However, the TA and TDA require accu rate knowledge of field speed and good time synchronization. It is not possible to accurately know while travelling through the body tissues due to complexity of the tissues. The AOA is also impractical for intra-body applications owing to multiple reflections signal from the tissues, commonly known as the multipath effect. The RSS precision is dependent on good knowledge of power loss in complex body tis sues. Also, the RSS method requires accurate knowledge of the transmitted signal strength. However, the power of transmitted frequencies may vary due to the ca pacitive effect of human tissue on Resonant frequency of source, hence RSS-based techniques prove difficult in practice. Therefore, a novel method of mapping the magnetic field vector in the near field region is proposed. This magnetic field mapping (MFM) uses single-axis coils placed orthogonally with respect to a sensor plane (SP). These single-axis sensors pick up only the orthogonal component of the magnetic field, which varies as a function of the orientation of the source and distance to the source. Thus, using this information, the field strength captured by each sensor is mapped to its correspond ing position on the SP as pixels. Next, these field strengths with known positions are used to detect the location and orientation of the field source relative to the SP. MATLAB and CST Microwave simulation were conducted, and many laboratory experiments were performed, and we show that the novel technique not only over comes the issues faced in the methods mentioned above but also accomplishes an accurate source positioning with a precision of better than ± 0.5 cm in 3-D and orientation with a maximum error of ±5◦