Capsule Orientation Research Articles

Capsules for the Diagnosis and Treatment of Gastrointestinal Motility Disorders- A Game Changer.

Over the last few decades, there have been remarkable strides in endoscopy and radiological imaging that have advanced gastroenterology. However, the management of neurogastroenterological disorders has lagged behind, in part handicapped by the use of catheter-based manometry that is both non-physiological and uncomfortable. The advent of capsule technology has been a game changer for both diagnostic and therapeutic applications. Here, we discuss several capsule devices that are available or under investigation. There are three technologies that are FDA approved. Wireless motility capsule measures pH and pressure and provides clinically impactful information regarding gastric, small intestine and colonic transit, without radiation that has been demonstrated to guide management of gastroparesis, dyspepsia and constipation. Wireless ambulatory pH monitoring capsule is currently the gold standard for assessing gastroesophageal acid reflux. In the therapeutics arena, an orally ingested vibrating capsule has been recently FDA approved for the treatment of chronic constipation, supported by a robust phase 3 clinical trial which showed significant improvement in constipation symptoms and quality of life. There are several capsules currently under investigation. Smart capsule bacterial detection system and Capscan® are capsules that can sample fluid in the small or large bowel and provide microbiome analysis for detection of small intestinal bacterial (SIBO) or fungal overgrowth (SIFO). Another investigational gas sensing capsule analyzing hydrogen, CO2, volatile fatty acids and capsule orientation, can measure regional gut transit time and luminal gas concentrations and assess gastroparesis, constipation or SIBO. Therapeutically, other vibrating capsules are in development. Innovations in capsule technology are poised to transform our ability to investigate gut function physiologically, and non-invasively deliver targeted treatment(s), thereby providing both accurate diagnostic information and luminally-directed, safe therapy.

Innovative Wireless Charging System for Implantable Capsule Robots

This article deals with an innovative wireless charging system for an implanted capsule robot. The transmitting coil is given by a combination of a Helmholtz coil and a birdcage coil. This coil configuration generates a magnetic field with all nonzero field components for any location within the human torso. Therefore, a single axis receiving coil wound around a cylindrical shaped ferrite core is able to receive a significant quantity of electrical energy for any capsule orientation and position. Design guidelines are provided and illustrative examples are given. Assuming a capsule of 2 cm length and 1 cm diameter we can transfer at least 1 W to the load with a minimum power transfer efficiency larger than 10% without considering electronic losses. Finally, compliance with electromagnetic field safety limits is assessed by a numerical dosimetric analysis.

Numerical study of suspensions of nucleated capsules at finite inertia

We perform simulations of suspension of capsules with nucleus in shear flow. Every capsule is modeled as a neo-Hookean hyperelastic membrane enclosing a rigid particle with radius equal to the half capsule radius. The rheology of the suspensions is related to the capsule deformation and orientation when varying the membrane stiffness and capsule volume fraction and compared to the dynamics of capsules without nucleus.

Octafilar Helical Antenna for Circular Polarization Wireless Capsule Endoscopy Applications

This paper introduces a proposed design of a circularly polarized quadfilar or octafilar helical antenna (QFHA or OFHA) dedicated for wireless in-body capsule endoscopy applications at 2.4 GHz. The use of a circularly polarized antenna permits a freedom in capsule orientation during endoscopy process. A multi-layered cylindrical model and homogenous cubic model for the human body tissues are studied and compared. The radiation characteristics of the QFHA and OFHA are encapsulated and placed inside the human model. Both the QFHA and the OFHA in capsule module are designed to resonate at 2.4 GHz with an impedance matching wide bandwidth of 125 MHz. The effect of the capsule ordination on the performance of the endoscopy process is studied. The response of the OFHA with and without capsulation is studied and introduced. The electrical length of an implantable antenna increases due to the high permittivity of the surrounding body tissues. The radiation characteristics of the QFHA and OFHA antennas in different cases are fully analysed and investigated using the finite integral technique.

Antenna System Design for Improved Wireless Capsule Endoscope Links at 433 MHz

Wireless capsule endoscopy (WCE) systems are used to capture images of the human digestive tract for medical applications. The antenna is one of the most important components in a WCE system. In this paper, we present novel small antenna solutions for a WCE system operating at the 433 MHz ISM band along with a link budget analysis. The in-body capsule transmitter uses an ultrawideband outer wall conformal loop antenna, whereas the on-body receiver uses a printed monopole antenna with a partial ground plane. A colon-equivalent tissue phantom and CST Gustav voxel human body model were used for the numerical studies of the capsule antenna. The simulation results in the colon-tissue phantom were validated through in vitro measurements using a liquid phantom. According to the phantom simulations, the capsule antenna has −10 dB impedance matching from 309 to 1104 MHz. The ultrawideband characteristic enables the capsule antenna to tolerate the detuning effects due to electronic modules in the capsule and due to the proximity of various different tissues in gastrointestinal tracts. The same design methodology was applied to on-body antennas followed by in vitro and ex vivo measurements for validation. The on-body antenna exceeds −10 dB impedance matching from 385 to 502 MHz both in simulations and measurements. The path loss for the radio link between an in-body capsule transmitter and an on-body receiver using our antenna solutions, in simulations and measurements, is less than 50 dB for any capsule orientation and location, ensuring sufficient signal level at the receiver, hereby enabling an improved capsule endoscope.

Quantification accuracy for dynamic contrast enhanced (DCE) CT imaging: phantom and quality assurance framework

PurposeStandardization and protocol optimization is essential for quantification of Dynamic Contrast Enhanced CT as an imaging biomarker. Currently, no commercially available quality assurance (QA) phantoms can provide for testing a complete set of imaging parameters pertaining to routine quality control for contrast-enhanced (CE) CT, as well as spatiotemporal accuracy. The purpose of this work was, therefore: (a) developing a solid calibration phantom for routine CE CT quality assurance; (b) investigating the sensitivity of CECT to organ motion, and (c) characterizing a volumetric CT scanner for CECT. MethodsCECT calibration phantom consisting of an acrylic uniform cylinder containing multiple capsules of varying diameters and orientations was designed and built. The capsules contain different solid density materials mimicking iodine contrast enhancement. Sensitivity and accuracy of CECT measurements on all capsules was performed using a 320-slice CT scanner for a range of scan parameters both with and without phantom motion along the transaxial axis of the scanner. ResultsRoutine commissioning tests such as uniformity, spatial resolution and image noise were successfully determined using the CECT phantom. Partial volume effect and motion blurring both contribute to a general decrease in contrast enhancement and this was further dependent on capsule orientation (least pronounced for the transaxial orientation). Scanning with a rotation time of less than 0.5 s, the effect of blurring is less than 3% for all orientations and phantom speeds. ConclusionA new robust contrast calibration phantom was developed and used to evaluate the performance of a 320-slice volumetric CT scanner for DCE-CT.

Surface characterization of ICF capsule by AFM-based profilometer

Outside surface fluctuations of inertial confinement fusion (ICF) capsule greatly affect the implosion performance. An atomic force microscope (AFM)-based profilometer is developed to precisely characterize the capsule surface with nanometer resolution. With the standard nine surface profiles and the complete coverage data, 1D and 2D power spectra are obtained to quantitatively qualify the capsule. Capsule center fast aligning, orbit traces automatic recording, 3D capsule orientation have been studied to improve the accuracy and efficiency of the profilometer.

Jacobian-Based Iterative Method for Magnetic Localization in Robotic Capsule Endoscopy.

The purpose of this study is to validate a Jacobian-based iterative method for real-time localization of magnetically controlled endoscopic capsules. The proposed approach applies finite-element solutions to the magnetic field problem and least-squares interpolations to obtain closed-form and fast estimates of the magnetic field. By defining a closed-form expression for the Jacobian of the magnetic field relative to changes in the capsule pose, we are able to obtain an iterative localization at a faster computational time when compared with prior works, without suffering from the inaccuracies stemming from dipole assumptions. This new algorithm can be used in conjunction with an absolute localization technique that provides initialization values at a slower refresh rate. The proposed approach was assessed via simulation and experimental trials, adopting a wireless capsule equipped with a permanent magnet, six magnetic field sensors, and an inertial measurement unit. The overall refresh rate, including sensor data acquisition and wireless communication was 7 ms, thus enabling closed-loop control strategies for magnetic manipulation running faster than 100 Hz. The average localization error, expressed in cylindrical coordinates was below 7 mm in both the radial and axial components and 5° in the azimuthal component. The average error for the capsule orientation angles, obtained by fusing gyroscope and inclinometer measurements, was below 5°.

Taxonomic Re-Assessment ofKindbergia(Brachytheciaceae, Bryophyta) in China, with a Description ofPseudokindbergiagen. nov.

Abstract — The distribution and systematic position of Kindbergia Ochyra in China is reevaluated. The phylogenetic analyses based on nuclear marker (ITS1-5.8S-ITS2) and chloroplastic markers (rpl16, trnG, and trnL-F) show that the alleged species of “Kindbergia” in China and Himalayas form a maximally supported clade (1.00 PP and 100 MPBS), which is closely related to the clade of Brachythecium Schimp., Eurhynchiadelphus Ignatov et Huttunen, and Myuroclada Besch., whereas the other Kindbergia specimens from Africa, America, Europe, Japan and the Southern Hemisphere form a monophyletic group, which is sister to Scleropodium Schimp. The specimens of Chinese species of “Kindbergia” are found, both molecularly and morphologically, to be identical with the Himalayan K. dumosa (Mitt.) Ignatov et Huttunen, and differ from Kindbergia specimens from other regions in the world in the shape of proximal branch leaves, operculum shape and capsule orientation. A new monotypic genus Pseudokindbergia M. Li, Y.F. Wang, Ig...

DOA-Based Endoscopy Capsule Localization and Orientation Estimation via Unscented Kalman Filter

The endoscopy capsule is a medical device capable of capturing images inside human's digestion system, specifically the small and big intestine. For medical diagnostics and surgery, it is required to know the position and direction of the image taken inside digestion system. This paper considers an alternative method of presurgery gastroscopy and colonoscopy monitoring procedure that allows the patient to freely move inside the medical ward. The direction-of-arrival (DOA) and inertial measurement unit (IMU) measurements are integrated to track the movement of capsule with respect to patient's body reference frame. The DOA is estimated via antenna arrays installed within a medical ward and the IMU is installed on the capsule endoscopy. The IMU sends the position information wirelessly to the antenna arrays in medical ward. Additional beacons are attached to the patient to allow body orientation and absolute position estimation due to the free movement. The nonhomogeneous nature of human body refracts the signal transmitted by the capsule, which leads to a highly nonlinear DOA function. This paper implements the unscented Kalman filter (UKF) to track the capsule by fusing the measurements made by DOA, IMU, and additional beacons attached to the patient. Simulations are conducted to investigate the capsule tracking and orientation estimation performance with respect to DOA resolution and beacons localization accuracy. Results confirm that compared with the DOA resolution, the beacons localization accuracy has a higher impact on the capsule orientation estimation performance. Furthermore, this paper investigates the impact of the number of available antenna arrays on multiplication required by UKF.

Development of a High Efficiency Dry Powder Inhaler: Effects of Capsule Chamber Design and Inhaler Surface Modifications

The objective of this study was to explore the performance of a high efficiency dry powder inhaler (DPI) intended for excipient enhanced growth (EEG) aerosol delivery based on changes to the capsule orientation and surface modifications of the capsule and device. DPIs were constructed by combining newly designed capsule chambers (CC) with a previously developed three-dimensional (3D) rod array for particle deagglomeration and a previously optimized EEG formulation. The new CCs oriented the capsule perpendicular to the incoming airflow and were analyzed for different air inlets at a constant pressure drop across the device. Modifications to the inhaler and capsule surfaces included use of metal dispersion rods and surface coatings. Aerosolization performance of the new DPIs was evaluated and compared with commercial devices. The proposed capsule orientation and motion pattern increased capsule vibrational frequency and reduced the aerosol MMAD compared with commercial/modified DPIs. The use of metal rods in the 3D array further improved inhaler performance. Coating the inhaler and capsule with PTFE significantly increased emitted dose (ED) from the optimized DPI. High efficiency performance is achieved for EEG delivery with the optimized DPI device and formulation combination producing an aerosol with MMAD < 1.5 μm, FPF<5 μm/ED > 90%, and ED > 80%.

Luminal View of an Intussusception Captured by Capsule Endoscopy

FigureA 6-year-old boy was investigated for iron-deficiency anemia refractory to oral supplementation. He did not have a history of abdominal pain or gastrointestinal bleeding, and stool microscopy was normal. Gastroscopy and colonoscopy were normal. To exclude an occult cause of gastrointestinal bleeding, a small-bowel capsule endoscopy (CE) was undertaken. The image/video (https://links.lww.com/MPG/A42) is a luminal view of a nonobstructive intussusception occurring at 1 hour 30 minutes into the small-bowel CE. It was asymptomatic and was not associated with any visible mucosal irregularity or blood in the lumen. No lead point such as a polyp was visualised during the study, and further investigations included a normal barium contrast follow-through study. No cause of his anemia has been identified to date. Gastrointestinal obstruction is a contraindication to performing a CE and should be excluded with imaging or the use of a degradable, radio-opaque patency capsule except in certain circumstances. Several studies have looked at the diagnostic yield of small-bowel CE in pediatrics, and the capture of an intussusception on CE is a noteworthy event because it is a rare occurrence (1). It is not possible to verify whether an intussusception is antegrade or retrograde unless one is absolutely certain of the capsule's orientation (the capsule lens can spin). In the present case the capsule passed through the intussusception with minimal delay, possibly reducing it with its passage. The smooth, moist surface suggests that there may be a bubble contributing the sheen seen in the image. The present case is a useful teaching point because it visually demonstrates an intussusception occurring as a normal physiological occurrence. In younger children, intussusception is thought to be caused by lymphoid hyperplasia. In older children and adults pathological lead points may be responsible for triggering the intussusception (2). Intussusceptions can present with abdominal mass, pain, bloody stool, and vomiting. Symptomatic intussusceptions can be treated pneumatically or surgically. Further investigations may be necessary to exclude a lead point such as adenitis, Peutz-Jeghers polyp, and carcinoma, if clinically indicated.

Dynamic rheology of a dilute suspension of elastic capsules: effect of capsule tank-treading, swinging and tumbling

Three-dimensional numerical simulations are used to study the effect of unsteady swinging and tumbling motion on the rheology of a dilute suspension of oblate-shaped elastic capsules. Unlike a suspension of initially spherical capsules undergoing the steady tank-treading motion for which the rheology is constant in time, the suspension of non-spherical capsules is time-dependent due to the unsteady capsule motion. In a simple shear flow, the non-spherical capsules undergo a transition from the tank-treading/swinging to the tumbling motion with a reduction in the shear rate or an increase in the ratio of the internal to external fluid viscosities. We find that the time-averaged rheology obtained for the non-spherical capsules undergoing the unsteady motion is qualitatively similar to that obtained for the spherical capsules undergoing the steady tank-treading motion, and that the tank-treading-to-tumbling transition has only a marginal effect. The time-averaged rheology exhibits a shear viscosity minimum when the capsules are in a swinging motion at high shear rates but not at low shear rates. This is a remarkable departure from the behaviour of a vesicle suspension which exhibits a shear viscosity minimum at the point of transition. We find that the shear viscosity in a capsule suspension can decrease as well as increase with increasing viscosity ratio during both tank-treading and tumbling motions, while that of a vesicle suspension always decreases in tank-treading motion and increases in tumbling motion. We then seek to connect the time-dependent rheology with the time-dependent membrane tension, capsule orientation, deformation and tank-treading velocity. At low shear rates, the numerical results exhibit a similar trend to that predicted by analytical theory for rigid ellipsoids undergoing tumbling motion. The trend differs during swinging motion due to the periodic deformation and time-dependent variation of the membrane stress. The elastic component of the shear stress is minimum when the capsules are maximally compressed, and is maximum when the capsules are maximally elongated. In contrast, the viscous component is related to the periodic variation of the tank-treading velocity synchronized with the swinging motion, and the rate of capsule elongation or compression. The swinging or tumbling velocity makes no contribution to the time-dependent rheology.

Monte Carlo calculation of dosimetry parameters for the IR08‐ brachytherapy source

PurposeFor the treatment of some cancerous tumors using brachytherapy methods and low‐energy photon sources, such as and , the American Association of Physicists in Medicine Task Group No. 43U1 report recommends that the dosimetric parameters of a new brachytherapy source must be determined in two experimental and Monte Carlo theoretical methods before using each new source clinically. This study presents the results of Monte Carlo calculations of the dosimetric parameters for IR08‐ brachytherapy source design. IR08‐ seed has been manufactured at the Agricultural, Medical and Industrial Research School.MethodsVersion 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. Three geometric models of the seed, based on different locations of beads inside the titanium capsule, were simulated. The seed contains five resin beads of 0.6 mm diameter having uniformly absorbed in the bead volume, which were contained within a cylindrical titanium capsule having 0.8 mm outside diameter and 4.8 mm length.ResultsThe Monte Carlo calculated dose rate constant of the IR08‐ seed was found to be . Also in this study, the geometry function , line and point‐source radial dose functions and , and the anisotropy function , have been calculated at distances from 0.25 to 7 cm. The results of these calculations have been compared with measured values for an actual IR08‐ seed.ConclusionsThere are no statistical significant dosimetric differences among the three seed orientations in this study (i.e., ideal, vertical, and diagonal). However, the observed differences between the calculated and measured values could be explained by the measurement uncertainty and the configuration of the resin beads within the capsule and capsule orientation.

A Wireless Insufflation System for Capsular Endoscopes

Swallowable capsule-based cameras (e.g., the Given Imaging PillCam and competitors) are rapidly becoming the gold standard for diagnosis in the gastrointestinal (GI) tract. However, definitive diagnosis is still often precluded by the inability to control capsule position and orientation. This has inspired a number of active positioning strategies including augmenting the capsule with legs or other appendages, or incorporating magnets which can apply forces and torques in response to an external magnetic field. Furthermore, the loose, mucous coated, elastic intestine is generally deflated during capsule passage, making it challenging to view the entire internal surface adequately without the insufflation that is relied upon in traditional endoscopy. To address these challenges, we propose a new fluid-powered system that permits insufflation from a wireless capsule platform. This is accomplished by carrying a small reservoir of biocompatible liquid onboard the capsule which vaporizes and expands when released through a small onboard solenoid valve. The internal components of the capsule consist of two 3V Lithium coin cell batteries (VL621, Panasonic, Inc.) which charge 3 Tantalum capacitors (TAJB157M006R, AVX Corporation, Inc.) that fire the solenoid valve (S120, Lee Company, Inc.). In our initial proof-of-concept study, we have packaged all components in a 26 mm long by 11 mm diameter capsule. The fluid used in initial experiments is biocompatible Perfluoropentane, although any of a variety of biocompatible fluids that can be liquefied with light pressurization may be used. Perfluoropentane, developed for lung lavage, is a liquid at room temperature and becomes gaseous at body temperature. We note that pneumatic pressure produced in this way may be used for a variety of objectives, including powering biopsy collection devices or other mechanisms within the capsule, or being vented to inflate the intestine. In initial experiments, we have harnessed the pressure to inflate a balloon at the front of the capsule which can distend tissue and thereby improve image quality. In experimental tests, only 0.2 ml of fluid was consumed in inflating the balloon to sufficient pressure to distend porcine intestine (see http://research.vuse.vanderbilt.edu/MEDLab for images of these experiments). Optimization of the capsule body and electrical components is currently underway. Including a wireless camera, all components are expected to fit within the dimensions of a commercial PillCam.

SU‐GG‐T‐07: I‐125 Seed Dosimetry in the Near Field Using Gafchromic® EBT Film

Purpose: To perform radiochromic EBT film dosimetry in the near field of model MED3631A/M I‐125 seed and to determine the TG‐43 dosimetric parameters. Method and Materials: Gafchromic® model EBT films (lot♯35076) were horizontally positioned, one at a time, above and in contact with a NAS model MED3631A/M I‐125 seed horizontally placed at the center of a solid water phantom (RMI457, 30×30×20cm3). A multiple‐film technique was employed. To cover the distance range of 0.06–5cm, 50 EBT films of different sizes (4×4–12×12cm2) were irradiated by 10 individual seeds (NIST traceable air kerma strengths ∼10U, based on current NAS calibration) using different exposure times (1–295hr). A separate set of 19 calibration films was exposed to 50kV x‐rays at 100 cm SSD for doses of 0.2–40Gy at the University of Wisconsin. All experimental, calibration and background films were scanned using a CCD100 densitometer using a green light source with fine spatial resolution (0.2mm). Based on the established calibration curve, dose conversion for the experimental films and generation of the TG‐43 dosimetric parameters (for L=4.2mm) were achieved using IDL v6.0. Results: The dose rate constant was 1.004 cGy/Uh. The radial dose function was obtained for the radial distances from 0.06 to 5cm. The 2D anisotropy functions for distances from 0.1 to 5cm were determined. General agreement with published values and those recommended by TG‐43U1 report for r⩾0.5cm was found. The near field data for 0.25cm is close to Rivard's Monte Carlo results for the “ideal capsule orientation”, but different from the TG43U1 consensus values based on Rivard's weighted “diagonal” and “vertical” capsule orientations. Conclusion: Using EBT film dosimetry with the multiple‐film technique, TG‐43 dosimetric parameters were determined for model MED3631A/M I‐125 seed in the near field and out to 5cm, allowing for accurate treatment planning calculations. Research supported partially by North American Scientific Inc.

각변위 방식을 이용한 캡슐의 오리엔테이션 측정 방법

본 논문은 각변위 방식을 이용한 소화경로 모델링 및 경로에 대한 캡슐의 오리엔테이션 측정 방법을 제안하였다. 제안하는 방법은 캡슐 내시경의 자세를 3차원 방향벡터와 이의 회전성분으로 표현하였다. 소화경로에 대한 캡슐의 오리엔테이션 정보인 롤, 피치 그리고 요우 값은 각각 <TEX>$1.6^{\circ}$</TEX> 이내의 오차를 보였다. 제안된 방법은 자기장을 이용한 오리엔테이션 측정에서 롤값 측정 문제를 해결하였다. 오일러 각을 이용한 기존의 오리엔테이션 측정 방식과 비교하여 알고리즘의 복잡도를 줄였다. In this paper, we propose an orientation tracking method and a digestion path model based on angular displacement. The proposed method expresses a capsule's orientation as 3-dimension vectors and its rotation angle. Errors in roll, pitch, and yaw representing capsule's orientation information is down to <TEX>$1.6^{\circ}$</TEX>. Using the proposed method we can measure a roll which is not Possible to be measured using the magnetic field method. We reduce algorithm complexity lower than a previous methods based on Euler angle.

The Distribution of Buxbaumia minakatae in Pennsylvania and the Lectotypification of B. subcylindrica

Buxbaumia minakatae S. Okamura was first reported for Pennsylvania from Allegheny County as B. indusiata Brid. A reexamination of this collection confirmed its identity. New distribution records of Buxbaumia minakatae are also added for Fayette and Westmoreland counties. The differences separating B. minakatae and B. aphylla are seta size, capsule orientation, and urn shape. A lectotype of B. subcylindrica Grout is chosen from the Grout herbarium induke.

Dwarf mistletoe seed capsule orientation and seed discharge in western hemlock

The seed discharge of Arceuthobium tsugense is closely related to the orientation of the seed capsule. The distribution of capsule orientations may therefore be used as a guide to the discharge pattern. With plants on the periphery of the crown, the azimuth orientation of the capsules directs seeds outward from the crown, whereas plants within the crown have an inward direction of azimuth capsule orientations. The distribution of vertical orientation angles is related to the growth angle of the branch bearing the infection. Infections near the crown periphery would appear to be more related to spread of infections, whereas those within the crown are related to intensification.