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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Computer Integrated Endoscopic Simulator with Nonlinear Distortion Correction System

Surangsrirat, Decho 01 January 2008 (has links)
The minimally invasive surgery or endoscopic surgery is the performance of surgery through a small incision with the aid of special medical equipment called a flexible endoscope. The advantage of this technique over open surgery is that there is significantly less operative trauma, resulting in less pain and shorter recovery time. Side effects of the surgery, such as the risk of infection, also reduce. Despite the tremendous benefits, surgeons require considerable practice and time to become competent in endoscopy. Traditionally, the procedure has been taught at the expense of patient comfort and safety as residents have performed the surgery under the supervision of physicians. Patients who undergo the endoscopies performed by students, particularly early in the training period, have been more likely to suffer more discomfort and prolonged procedures. Therefore, using the simulator becomes a promising alternative for endoscopic training process. Our approach is to integrate the computer system with a realistic mechanical model to create a computer-based simulator for upper endoscopy training. The simulator will cover the basics of flexible endoscopy and teach the student the skills required to perform the upper endoscopy. The mechanical training model that simulates a human upper gastrointestinal tract, including pathologies such as ulcers and polyps, will be built and integrated with computer software that will both help and evaluate the student. Due to the optical system of an endoscope, a barrel-type spatial distortion of the image is obtained which results in an inconsistent measurement of object size and distance. The distortion correction system, which includes automatic calibration and expansion coefficients calculation, offers a better perception of size and distance from the endoscopic images to the trainee. With the completion of the distortion correction system, an evaluation system including object recognition can be implemented with high accuracy. Finally, the results of visual observation and numerical analysis are discussed. A recommendation for further study is enclosed.
2

Amplifying contact force sensitivity in soft optical waveguides for use in soft robotics

Baldiswieler, Mark 24 May 2022 (has links)
Surgical robotic systems with rigid components have been extensively researched as methods to assist in various medical procedures and surgeries. While these systems have been highly effective in assisting a variety of minimally invasive surgeries, they are restricted to discrete motions, and do not provide the flexibility or compliance necessary for applications that require navigation through the tortuous paths of the body. Recent growth and development in the field of soft robotics have allowed researchers to overcome many of these restrictions with the potential to exceed the performance of rigid robotics. However, soft robotic sensing capabilities still leave much to be desired in a field where accuracy and sensitivity are key. Previous work on a soft robotic sleeve with embedded soft optical force sensors has shown the potential for soft optical waveguides to be a viable method of improving navigation and safety in colonoscopy procedures. Here, we improve upon this work through a complete overhaul of the soft optical waveguide architecture to allow for increased contact force sensitivity and the ability to detect distributed forces all while boasting a significantly thinner physical profile. This is accomplished through the integration of advanced hybrid stiffness structures, fabrication techniques, mechanical design, and core material into an updated sleeve. The sleeve’s performance is then validated in a testing environment simulating the forces displayed in a human colon during colonoscopy procedures. / 2025-05-31T00:00:00Z
3

Ultrahigh-Resolution Endoscopic Optical Coherence Tomography for In Vivo Mouse Colonoscopy

Tumlinson, Alexandre Rex January 2007 (has links)
In vivo monitoring of mouse models of colon cancer promises to reduce the cost of research by improving sacrifice timing and allowing serial studies that observe the progression of disease and drug efficacy in a relatively small set of animals. Optical coherence tomography (OCT) is an optical analog of ultrasound imaging, capable of minimally-invasive mapping of light scatter intensity up to 2 mm deep in tissue. In this work, factors limiting resolution in OCT were examined and devices were created and applied to mouse colon imaging that extended the state-of-the-art in endoscopic ultrahigh-resolution OCT. First, axial chromatic aberration of the objective optics acts as a spectral filter in the sample arm limiting the effective bandwidth of the system. An achromatized endoscope design was demonstrated that achieved axial resolution of 2.3 mum in tissue and 4.4 mum lateral spot diameter with 101 dB sensitivity when interfaced with a time domain OCT system utilizing a 10-femtosecond laser (bandwidth=150 nm FWHM, center wavelength=800 nm). Second, dispersion matching between the sample and reference arms presents the practical resolution limit to endoscopic implementations including a separate, fiber-based reference arm. A second endoscope incorporated the reference arm into the tip of the endoscope using a novel custom beamsplitter prism and achieved 2.4 mum axial resolution in tissue without adjustments for pathlength or dispersion matching when interfaced with a spectrometer-based frequency domain OCT system and a similar laser. Third, non-linear dispersion of the sample media with respect to wavelength causes distortion and broadening of the axial point spread function when data are sampled uniformly in optical frequency. An experiment was performed on high dispersion glass to demonstrate that dispersion artifact free imaging can be achieved without post process corrections if the samples are acquired at equal intervals of media index of refraction divided by vacuum wavelength. Finally, other microscopic modalities that depend on tissue scatter intensity are used to find the origins of scatter in the mouse colonic mucosa. These observations are used to explain unexpected features found in ultrahigh-resolution tomograms collected with the two endoscopes presented.
4

Development of an Endoscope Propulsion System to Aid in the Colonoscopy Procedure

Tenga, Ryan Richard 16 January 2008 (has links)
Colorectal cancer is the third most common form of cancer, and is the number two cancer-related death in the United States. Receiving regular colonoscopies can reduce the average person's risk of dying from colon cancer by 90%. However, only 54% if adults over the age of 50 get regular colonoscopies. This low percentage can be attributed to the exam's poor availability, severe discomfort, high cost, and the risk of procedural complications. The Endoscope Propulsion System, or EPS, will assist in the colonoscopy procedure. This device will enable a lesser skilled physician to effectively perform the colonoscopy, thus increasing the procedure's availability. In addition to requiring less skill, the assistive nature of the EPS will also decrease the chance of complications due to colon perforation. The EPS will greatly reduce the discomfort cause by the colonoscope, which will eliminate the need for anesthesia and recovery, therefore greatly reducing the cost of the procedure. The Endoscope Propulsion System design described in this paper is an update to the device outlined in Dr. M. Jonathan Bern's patent application (20060270901). The criteria and requirements of the design are discussed along with the final design and analysis. Finally, a prototype was built to ensure the validity of the proposed invention. / Master of Science
5

Hyperspectral endoscopy imaging: system development, clinical evaluation, and further application

Han, Zhimin 27 May 2016 (has links)
Hyperspectral (HS) imaging combines spectral measurement of a pixel with 2D imaging technology. It is capable to provide a series of images containing both spectral and spatial information, and has been widely used in medical domain. However, most researches on medical HS imaging are regarding ex-vivo biopsy or skin and oral mucosa. The study on HS imaging regarding in-vivo disease lags far behind. In this thesis, we developed a novel flexible HS endoscope system. It is capable to obtain a series of HS images in vivo in a non-contact way among the wavelength range of 405 – 665 nm. After a lot of time-consuming modifying and debugging work, this new system has high stability and convenience to be applied in clinic now. We evaluated this system in clinic. First, we got ethics approval for clinical trials. Then, we obtained HS images regarding gastrointestinal (GI) diseases inside patients using this system. As far as we know, this type of in-vivo image data has not been reported in previous literatures. Thus using these HS images, we built a database for GI mucosa. Next, we analyzed some typical HS images tentatively. The method of Recursive Divergence is implemented to extract valuable and diagnostic information from these HS images. The results prove the effect and applicability of this new HS endoscope system, which has shown the great potential to be used as a platform and guidance for further medical studies. To further apply the analysis results in clinic, we propose a novel Adaptive Narrow-Band Imaging (ANBI) method based on band selection of HS images of a specific type of disease. It is expected that the new technique has higher accuracy, sensitivity, and specificity compared to conventional Narrow-Band Imaging (NBI) technique. In this thesis, we also discuss the future direction of the system improvement. Especially, to improve light intensity and signal-noise-ratio of HS images in wide-field view, we propose a new imaging method using broad- and overlapped-band filters. Although this method only performs greatly on the foundation of accurate image registration, we hope to apply it in our system in the future.
6

Design, development and testing of miniature instruments for flexible endoscopy

Gong, Feng January 1999 (has links)
No description available.
7

PROJECTED FRINGE PROFILOMETRY USING A HOLOGRAPHIC TECHNIQUE: A COMPACT DESIGN FOR ENDOSCOPES

Hsiao, Chih-Hung 08 August 2008 (has links)
This paper proposes a miniature gauging system for objects inside a body cavity using the projected fringe profilometry (PSPFP) combined with the endoscope. The fringe pattern is formed by launching a reading bean into a diffraction element . The diffraction element can avoid the influence of projected aberrations by lens and largely reduce the size of projected system. This system has the following properrties: 1. It is a noon-contact, and full field measurement. Only one-shot measurement is needed. It is able to carry on the immediate gauging to the dynamic object. 2. Arrangement of the projected fringe is unique due to the procedure of specific coding. It is easy to revise the errors when undergo phase unwrapping. 3. The double projection scheme compensates the defects of one-shot measurements.
8

Dual Field of View Optical System for Colonoscope

Katkam, Rajender January 2014 (has links)
The present dual field of view flexible colonoscope can provide both forward view and radial or backward view of the colon to improve detection of cancerous polyps. The colonoscope has its own illumination that illuminates the parts of the colon viewed by imaging optics. The optical system, limited only by the diffraction effects at the exit pupil over the entire visible spectrum, can provide high resolution and is suitable for color imaging. The flexible colonoscope has an on-board sensor at the proximal end of the colonoscope to improve resolution. The proximal end of colonoscope measures only 8 mm in diameter and 20 mm in length. The present colonoscope has the potential to be scaled down to as small as 6 mm inner diameter from the present 8 mm.
9

Clinical and Cost Utility of an Intraoperative Endoscopic Second Look in Cholesteatoma Surgery

Bennett, Marc, Wanna, George, Francis, David, Murfee, Jack, O'Connell, Brendan, Haynes, David 01 December 2018 (has links)
Objective/Hypothesis: This study aimed to determine the clinical and cost-effectiveness of endoscopes during cholesteatoma surgery. More specifically, this study hypothesized that endoscope use would reduce cholesteatoma recurrence rates and cost. Study Design: Case series involving the prospective enrollment of 110 consecutive cholesteatoma patients over a 2-year period. Methods: Patients underwent cholesteatoma surgery with microscopy. During dissection, the location of the cholesteatoma was assessed. At the end of dissection and before reconstruction, the same subunits were visualized with straight and angled endoscopes for residual cholesteatoma. Hearing was analyzed before surgery and at the last possible examination. Costs were analyzed using Medicare reimbursement rates from the Centers for Medicare and Medicaid Services. Results: Intraoperative endoscopic surveillance was able to detect residual cholesteatoma in 18 patients. With a 0° endoscope, residual cholesteatoma was noted in the epitympanum (two patients), sinus tympani (one patient), and the supratubal air cells (one patient). With a 45° endoscope, residual cholesteatoma was noted in the epitympanum (three patients), sinus tympani (nine patients), the supratubal air cells (two patients), and the mesotympanum (two patients). From a cost analysis, endoscopic surveillance ($6110.36 per patient) are less expensive than second look surgeries ($11,829.83 per patient), observation ($7097.20 per patient), and observation with annual magnetic resonance imaging studies ($9891.95 per patient). The patients hearing improved after surgery, consistent with previous studies. No complications were noted from the use of endoscopes. Conclusions: Intraoperative endoscopic surveillance reduced recurrence in our series of 110 patients. Endoscopes are particularly useful in evaluating the epitympanum, mesotympanum, sinus tympani, and supratubal air cells. Moreover, endoscopic surveillance is cost-effective. Level of Evidence: 4 Laryngoscope, 128:2867–2871, 2018.
10

O impacto da fricção, solução de limpeza e subsequente desinfecção de alto nível na remoção de biofilme buildup-5 e de biofilme tradicional-5 em canais endoscópicos gastrointestinais flexíveis / The impact of friction, and cleaning solution and subsequent high-level disinfection in removal cyclic buildup biofilm and cyclic biofilm on flexible endoscopic gastrointestinal channels

Ribeiro, Maíra Marques 22 August 2016 (has links)
Introdução: Biofilme consiste em um conjunto de microrganismos embutidos em uma matriz extracelular. O biofilme tradicional (TBF) se desenvolve em locais com contínua hidratação, e o biofilme buildup (BBF), em produtos para a saúde expostos a repetidos ciclos de sujidade, limpeza, desinfecção e secagem. Objetivo: avaliar o impacto do uso de detergente e fricção para remover biofilme buildup-5 (BBF-5) e biofilme tradicional-5 (TBF-5) de canais endoscópicos gastrointestinais flexíveis, bem como o impacto do glutaraldeído após a limpeza. Métodos: O BBF-5 foi desenvolvido após a exposição da superfície interna dos canais de endoscópicos gastrointestinais ao Artificial Test Soil (ATS) contendo 108UFC/ml de Pseudomonas aeruginosa (PA) e Enterococcus faecalis (EF), limpeza, desinfecção de alto nível (DAN), enxágue e secagem durante cinco dias. O mesmo processo foi utilizado para desenvolver o TBF-5, porém a fase de DAN foi omitida. Limpeza com detergentes com enzimas de pH neutro e detergentes sem enzimas com pH alcalino, escova com cerdas e dispositivo de limpeza pull thru foram comparados à limpeza com água e sem fricção para remover o BBF-5 e o TBF-5. Testes de proteína e carboidrato, contagem de bactérias viáveis e adenosina trifosfato (ATP) foram realizados. Teste de Kruskal-Wallis e análise de post hoc Dunn-Bonferroni foram realizados. Resultados: Não houve diferença estatisticamente significante (p>0,05) entre a quantidade de EF e PA nos canais com TBF-5 e BBF-5. Não houve diferença da eficácia para a remoção de PA em TBF-5 entre o detergente enzimático e a água, em ambas as situações, a limpeza apenas não foi eficaz (p>0,05) na ausência de fricção (flush). Por outro lado, o detergente alcalino, associado a todos os procedimentos de limpeza (ausência e presença de fricção) e DAN, foi eficaz para remoção de PA. Para a remoção de EF em TBF-5, a eficácia da limpeza foi alcançada em todas situações avaliadas (com e sem fricção) com o uso do detergente enzimático; com a água, na presença de fricção (pull thru e escovas de cerdas); e com detergente alcalino, apenas com o método de limpeza com escovas de cerdas (p<0,05). Para a remoção de bactérias em BBF-5, formados em canais de PTFE, não houve diferença da eficácia para a remoção de PA entre o detergente enzimático e o alcalino, em ambas situações, todos os procedimentos avaliados foram eficazes (p<0,05), enquanto que a água foi ineficaz para remoção de PA apenas na ausência de fricção (p>0,05). Para a remoção de EF em BBF-5, o detergente enzimático e a água foram eficazes em todas situações avaliadas; o detergente alcalino, foi eficaz na presença de fricção com o dispositivo pull thru e escovas de cerdas (p<0,05). Testes de ATP, proteína e carboidrato foram incapazes de detectar biofilme. Conclusão: Água potável de torneira, detergente com enzimas e detergente alcalino sem enzimas foram eficazes para a completa remoção de BBF-5 e TBF-5 na presença de fricção (pull thru ou escova com cerdas) durante a limpeza. Na ausência de fricção, detergente enzimático apresentou maior habilidade para remover E. faecalis de TBF-5 e BBF-5, detergente alcalino para remover P. aeruginosa e a água não foi eficaz para a remoção de ambos microrganismos. Glutaraldeído destruiu bactérias remanescente após a maioria das combinações de limpeza avaliadas. / Background: Biofilm is the accumulation of microorganisms enclosed in an extracellular matrix. Traditional biofilm (TBF) develops under continuous hydration whereas buildup biofilm (BBF) develops on medical devices that are exposed to repeated cycles of soiling, cleaning, disinfection and drying. Objetive: to evaluat the impact of detergent and friction on BBF-5 and and TBF-5 removal from PTFE channels as well as the killing efficacy of glutaraldehyde post cleaning. Methods: BBF-5 was developed by repeated rounds over five days of exposure to bacteria, cleaning, high level disinfection (HLD), rinsing and drying of the inner surface of new polytetrafluorethylene (PTFE) channels. Artificial Test Soil (ATS) containing 108CFU/ml of Pseudomonas aeruginosa (PA), and Enterococcus faecalis (EF) was used for the bacterial exposure. The same process was used to develop TBF-5, however the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush and pull thru cleaner were compared to a water-flush only to determine BBF-5 and TBF-5 removal. The residual organic and microbial levels were tested using carbohydrate, and protein assays as well viable count, and adenosine triphosphate (ATP) testing. Kruskal-Wallis test and the post hoc Dunn-Bonferroni analysis were performed. Results: There was not a statistically significant difference (p> 0.05) between the amount of EF and PA in the channels with TBF-5 and BBF-5. There was not a difference in efficacy for the removal of PA in TBF- 5 between the enzymatic detergent and water and in both situations, only cleaning was not effective (p>0.05) in the absence of friction (flush). Furthermore, the alkaline detergent, associated with all cleaning procedures (absence and presence of friction) and DAN, was effective for the removal of PA. For removal of EF in TBF-5, cleaning efficacy was achieved in all procedures evaluated (with and without friction) with the use of enzymatic detergent; with water in the presence of friction (pull thru and bristle brushes); and an alkaline detergent, the only method of cleaning brushes with bristles (p<0.05). For the removal of bacteria in BBF-5 formed on PTFE channels, there was not a difference in efficacy for PA removal of the enzymatic and alkalyne detergent and in both situations, all procedures were evaluated effective (p<0.05 ), while water was ineffective for PA removal only in the absence of friction (p>0.05). For EF removal on BEF-5, the enzymatic detergent and water were evaluated effective in all situations; alkaline detergent, was effective in the presence of friction with the pull thru device and bristle brushes (p<0.05). ATP, protein and carbohydrate testing were unable to detect biofilm. Conclusion: Tap water, enzymatic and alkaline detergent were effective for complete BBF-5 and TBF-5 removal in the presence of friction (pull thru or bristle brush) and a flushing pump during the cleaning. Without friction, enzymatic detergent was more effective for EF removal of TBF-5 and BBF-5, alkalyne detergent was more effective for PA removal and water was not effective for both types of bacterial removal. Glutaraldehyde effectively killed the remaining microorganisms after some cleaning combinations were tested.

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