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Pose estimation and localization within the gastrointestinal tract, particularly the small bowel, are crucial for invasive medical procedures. However, the task is challenging due to the complex anatomy, homogeneous textures, and limited distinguishable features. This study proposes a hybrid deep learning (DL) method combining Convolutional Neural Network (CNN)-based pose estimation and optical flow to address these challenges in a simulated small bowel environment. Initial pose estimation was used to assess the performance of simultaneous localization and mapping (SLAM) in such complex settings, using a custom endoscope prototype with a laser, micromotor, and miniaturized camera. The results showed limited feature detection and unreliable matches due to repetitive textures. To improve this issue, a hybrid CNN-based approach enhanced with Farneback optical flow was applied. Using consecutive images, three models were compared: Hybrid ResNet-50 with Farneback optical flow, ResNet-50, and NASNetLarge pretrained on ImageNet. The analysis showed that the hybrid model outperformed both ResNet-50 (0.39 cm) and NASNetLarge (1.46 cm), achieving the lowest RMSE of 0.03 cm, with feature-based SLAM failing to provide reliable results. The hybrid model also gained a competitive inference speed of 241.84 ms per frame, outperforming ResNet-50 (316.57 ms) and NASNetLarge (529.66 ms). To assess the impact of the optical flow choice, Lucas–Kanade was also implemented within the same framework and compared with the Farneback-based results. These results demonstrate that combining optical flow with ResNet-50 enhances pose estimation accuracy and stability, especially in textureless environments where traditional methods struggle. The proposed method offers a robust, real-time alternative to SLAM, with potential applications in clinical capsule endoscopy. The results are positioned as a proof-of-concept that highlights the feasibility and clinical potential of the proposed framework. Future work will extend the framework to real patient data and optimize for real-time hardware.

Although liver biopsy is a well-established technique to assess fibrosis it has several limitations, including invasive nature, semi-quantitative assessment methods, significant sampling and observer variability, making precise assessment of hepatic fibrosis challenging. Accurate and reliable modalities are crucial for clinical trials to characterize hepatic fibrosis monitorization effectively. We aimed to perform 3-dimensional imaging of optically transparent liver samples by light-sheet microscopy (LSM) to quantify extracellular matrix (ECM) proteins. Fifty-seven MASLD, thirty-eight chronic hepatitis patients and twelve healthy individuals were included. Liver tissues were cleared with a CLARITY method. 3D imaging of ECM was performed via the newly developed LSM. Collagen Proportionate Volume (CPV) and Elastin Proportionate Volume (EPV) values were calculated by analysis of over 200 sections per sample through morphometry. We have optimized a method which achieves transparency of liver tissues in advanced fibrotic stages of MASLD and optimized non-destructive slide-free fibrosis pathology of whole fresh and FFPE liver biopsy samples. Cut-off values for CPV and EPV were established for fibrotic stages. CPV and EPV analysis showed a considerable optical section heterogeneity resulting in a fibrosis stage of variance within the sample. Volumetric image analysis for fibrosis staging revealed that only 44% and 47% of optical sections would be staged the same for F3 and F4, respectively. For the first time, our findings demonstrate a novel method of analyzing 3D digital pathology of liver fibrosis using in-house LSM. Volumetric imaging of whole liver biopsy samples showed that fibrosis heterogeneity occurs even in different sections.

Capsule endoscopy offers a non-invasive and patient-friendly method for imaging the gastrointestinal tract, boasting superior tissue accessibility compared to traditional endoscopy and colonoscopy. While advances have led to capsules capable of drug delivery, tactile sensing, and biopsy, size constraints often limit a single capsule from having multifunctionality. In response, we introduce multi-capsule endoscopy, where individually ingested capsules, each with unique functionalities, work collaboratively. However, synchronized navigation of these capsules is essential for this approach. In this paper, we present an active distance control strategy using a closed-loop system. This entails equipping one capsule with a sphere permanent magnet and the other with a solenoid. We utilized a Simulink model, incorporating (i) the peristalsis motion on the primary capsule, (ii) a PID controller, (iii) force dynamics between capsules through magnetic dipole approximation, and (iv) position tracking of the secondary capsule. For practical implementation, Hall effect sensors determined the inter-capsule distance, and a PID controller adjusted the solenoid’s current to maintain the desired capsule spacing. Our proof-of-concept experiments, conducted on phantoms and ex vivo bovine tissues, pulled the leading capsule mimicking a typical human peristalsis speed of 1 cm/min. Results showcased an inter-capsule distance of 1.94 mm ± 0.097 mm for radii of curvature at 500 mm, 250 mm, and 100 mm, aiming for a 2-mm capsule spacing. For ex vivo bovine tissue, the achieved distance was 0.97 ± 0.28 mm against a target inter-capsule distance of 1 mm. Through the successful demonstration of precise inter-capsule control, this study paves the way for the potential of multi-capsule endoscopy in future research.

We conducted a series of experimental investigations to generate laser-stimulated millimeter bubbles (MBs) around silver nanoparticles (AgNPs) and thoroughly examined the mechanism of bubble formation within this nanocomposite system. One crucial aspect we explored was the lifetime and kinetics of these bubbles, given that bubbles generated by plasmonic nanoparticles are known to be transient with short durations. Surprisingly, our findings revealed that the achieved lifetime of these MBs extended beyond seven days. This impressive longevity far surpasses what has been reported in the existing literature. Further analysis of the experimental data uncovered a significant correlation between bubble volume and its lifetime. Smaller bubbles demonstrated longer lifetimes compared to larger ones, which provided valuable insights for future applications. The experimental results not only confirmed the validity of our model and simulations but also highlighted essential characteristics, including extended lifetime, matching absorption coefficients, adherence to physical boundary conditions, and agreement with simulated system parameters. Notably, we generated these MBs around functionalized AgNPs in a biocompatible nanocomposite medium by utilizing low-power light excitation. By readily binding potent cancer drugs to AgNPs through simple physical mixing, these medications can be securely encapsulated within bubbles and precisely guided to targeted locations within the human body. This capability to deliver drugs directly to the tumor site, while minimizing contact with healthy tissues, can lead to improved treatment outcomes and reduced side effects, significantly enhancing the quality of life for cancer patients.

Purpose Capsule endoscopy offers increased patient comfort and improved visibility of the entire gastrointestinal (GI) tract. Besides imaging, numerous literary studies on capsule endoscopy have demonstrated drug delivery, navigation strategies, tactile sensing for tumor diagnosis, and biopsy. Yet, the size limitation hampers the availability of multiple features within a single capsule. In an effort to increase the space and functionality, we propose the use of multiple capsules. Methods All capsules together form a capsule-train, whose wagons are connected with magnetic push/pull forces. Magnets located on each capsule form the virtual magnetic spring. The presence of a preset gap allows for joint tasks on the targeted tissue. The gap in-between capsules also ensures ease of motion throughout the GI, while negating the risk of clinching of tissue parts in between the capsules. Results Designed capsule train with two capsules successfully traveled through straight phantom without breaking connection for typical bowel speed. Also, same experiment is repeated with higher (2 × to 16 × of expected) speeds to inspect possible abrupt conditions, where capsules traveled together without any disconnection while maintaining constant distance in-between. Experiment results successfully imitate the developed magnet spring model (10–30% mismatch) even with ignored friction forces and camera pixilation errors. Conclusion As future work, we will be working on adapting the capsule train for curved trajectories and perform demonstrations on ex-vivo animal bowel models. With further development, magnetically connected multi-capsule train can be adapted to clinic for improved functionality and multitasking through the GI tract.

We present a simple, low-cost and effective method to monitor mode-shapes of dynamic structures, based on laser triangulation. Through the smart adjustment of the camera view angle, we were able to acquire the mode-shapes on two orthogonal planes, without the need to change the placement of neither the device-under-test, nor the illumination or detection optics. The presented technique was demonstrated on two different miniaturized dynamic structures for laser-scanned optical imaging both having ~ 1 cm 2 floor area; a 3D-printed electromagnetically-actuated laser scanner, and an orthogonally placed double piezoelectric cantilever structure for fiber scanning. Experimental findings reveal a good match with the observations made on finite-element simulations. Based on its cost advantage (only requiring 1–2 laser, a cylindrical lens, and a standard CMOS camera) and simplicity (both setup and software), the presented method is particularly appealing to characterize MEMS and similar dynamic structures on multiple planes, performing periodic motion. Moreover, the method is scalable to smaller structures having ~ 1 mm 2 floor area, and higher modal frequencies.

We present the design and deployment of a capsule endoscope via external electromagnets for locomotion in large volumes alongside its digital twin implementation based on interval type-2 fuzzy logic systems (IT2-FLSs). To perform locomotion, we developed an external mechanism comprising five external electromagnets on a two-dimensional translational platform that is to be placed underneath the patients’ bed and integrated multiple Neodymium magnets into the capsule. The interaction between the central bottom external electromagnet and the internal magnet forms a fixed body frame at the capsule center, allowing rotation. The interaction between the external electromagnets and the two internal magnets results in rotation. The elevation of the capsule is accomplished due to the interaction between the upper external electromagnet and the internal magnets. Through simulations, we model the capsule rotation as a function of torque and drive voltages. We validated the proposed locomotion approach experimentally and observed that the results are highly nonlinear and uncertain. Thus, we define a regression problem in which IT2-FLSs, capable of representing nonlinearity and uncertainty, are learned. To verify the proposed locomotion approach and test the IT2-FLS, we leverage our experimental effort to a stomach phantom and finally to an ex vivo bovine stomach. The experimental results validate the locomotion capability and show that the IT2-FLS can capture uncertainties while resulting in satisfactory prediction performance. To showcase the benefit in a clinical scenario, we present a digital twin implementation of the proposed approach in a virtual environment that can link physical and virtual worlds in real time.

We present a low-cost and biocompatible 3D-printed fluidic device composed of a main body and two lids with membranes in between forming a tunable lens. The main body and the lids of the device is manufactured using stereolithography (SLA) technology and comprises of one or two inlets. Collagen type-I enriched Sodium Alginate membranes are sandwiched between the main body and the top and the bottom lids. A syringe pump is employed to control the amount of liquid inside the chamber, thus tuning the radius of curvature of both membranes. The device dimensions are chosen as 15 × 10 × 7 mm 3 (length × width × height), towards integration with previously developed miniaturized 3D-printed laser scanning imagers, offering focus adjustment capability. The extracted collagen, which is mixed with the membrane material, offers (1) a lens-mimicking structure, (2) biocompatibility, and (3) capability of tailoring membrane mechanical properties through adjusting collagen mass ratio. Using the manufactured device, we demonstrate focus tuning, hysteresis characterization and resolution target imaging experiments conducted at different target distances. The 3D-printed tunable lens structure is suitable for integration with a wide range of minimally invasive laser scanned imagers or ablation units presented in the literature.

Side viewing, miniaturized laser scanning endoscopes are powerful tools in providing sub-cellular level resolution and multi-layered imaging of the walls of body cavities. Yet, the level of miniaturization for such devices is significantly hampered by the necessity for 45° placement of the whole scanner unit with respect to the cavity axis. With its rapid and low-cost production capability, 3D printing can be employed in addressing the challenge of producing a laser scanner, whose scanning head makes 45°, or any desired angle, with the scanner unit. Producing a 10 × 10 mm 2 scanner device with tilted scan head (as opposed to the conventional design with identical size) enabled size shrinkage of a near fully 3D-printed laser scanning imager by × 1.5 in diameter (from 17 to 11 mm). We also share the initial results on 5 × 5 mm 2 total die size scanners, having literally identical die size with their MEMS counterparts, and discuss the road steps in producing < 8-mm diameter laser scanning devices with these scanners using 3D printing technology. The frame-rate improvement strategies are discussed in detail. Furthermore overall resolution and frame-rate values that can be achieved with the presented 3D printed scanners are tabulated and compared to MEMS counterparts. Overall with their low cost, easy and rapid fabrication, 3D printed actuators are great candidates for opto-medical imaging applications.

Applicability of the Mueller Matrix (MM) polarimetry for the optical characterization of the olive and sunflower oils were tested. For this aim, linear dichroism and optical rotation of circular birefringence of the oil samples divided into three comparable groups as pure olive oil (heated and non-heated), pure sunflower oil (heated and non-heated) and mixture of olive oil and sun flower were measured. Principal Component Analysis was also utilized in interpreting the results, through dimensional reduction. Results reveal the potential of using MM polarimetry as a low cost and simple method in authentication of olive oil, as opposed to its higher cost and complex alternatives such as Raman Spectrometry, Chromatography and NMR.