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1.
Int J Comput Assist Radiol Surg ; 16(8): 1393-1401, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34224068

RESUMO

PURPOSE: We present the validation of PROST, a robotic device for prostate biopsy. PROST is designed to minimize human error by introducing some autonomy in the execution of the key steps of the procedure, i.e., target selection, image fusion and needle positioning. The robot allows executing a targeted biopsy through ultrasound (US) guidance and fusion with magnetic resonance (MR) images, where the target was defined. METHODS: PROST is a parallel robot with 4 degrees of freedom (DOF) to orient the needle and 1 DOF to rotate the US probe. We reached a calibration error of less than 2 mm, computed as the difference between the needle positioning in robot coordinates and in the US image. The autonomy of the robot is given by the image analysis software, which employs deep learning techniques, the integrated image fusion algorithms and automatic computation of the needle trajectory. For safety reasons, the insertion of the needle is assigned to the doctor. RESULTS: System performance was evaluated in terms of positioning accuracy. Tests were performed on a 3D printed object with nine 2-mm spherical targets and on an anatomical commercial phantom that simulates human prostate with three lesions and the surrounding structures. The average accuracy reached in the laboratory experiments was [Formula: see text] in the first test and [Formula: see text] in the second test. CONCLUSIONS: We introduced a first prototype of a prostate biopsy robot that has the potential to increase the detection of clinically significant prostate cancer and, by including some level of autonomy, to simplify the procedure, to reduce human errors and shorten training time. The use of a robot for the biopsy of the prostate will create the possibility to include also a treatment, such as focal ablation, to be delivered through the same system.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Biópsia Guiada por Imagem/métodos , Neoplasias da Próstata/diagnóstico , Robótica/métodos , Software , Biópsia por Agulha/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Imagens de Fantasmas , Projetos Piloto , Ultrassonografia
2.
IEEE Trans Biomed Eng ; PP2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34156935

RESUMO

In Robot Assisted Minimally Invasive Surgery, discriminating critical subsurface structures is essential to make the surgical procedure safer and more efficient. In this paper, a novel robot assisted electrical bio-impedance scanning (RAEIS) system is developed and validated using a series of experiments. The proposed system constructs a tri-polar sensing configuration for tissue homogeneity inspection. Specifically, two robotic forceps are used as electrodes for applying electric current and measuring reciprocal voltages relative to a ground electrode which is placed distal from the measuring site. Compared to the other existing electrical bioimpedance sensing technology, the proposed system is able to use miniaturized electrodes to measure a site flexibly with enhanced subsurfacial detection capability. In this paper, we present the concept, the modeling of the sensing method, the hardware design, and the system calibration. Subsequently, a series of experiments are conducted for system evaluation including finite element simulation, saline solution bath experiments and experiments based on ex vivo animal tissues. The experimental results demonstrate that the proposed system can measure the resistivity of the material with high accuracy, and detect a subsurface non-homogeneous object with 100% success rate. The proposed parameters estimation algorithm is able to approximate the resistivity and the depth of the subsurface object effectively with one fast scanning.

3.
Int J Comput Assist Radiol Surg ; 16(7): 1111-1119, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34013464

RESUMO

PURPOSE: Automatic segmentation and classification of surgical activity is crucial for providing advanced support in computer-assisted interventions and autonomous functionalities in robot-assisted surgeries. Prior works have focused on recognizing either coarse activities, such as phases, or fine-grained activities, such as gestures. This work aims at jointly recognizing two complementary levels of granularity directly from videos, namely phases and steps. METHODS: We introduce two correlated surgical activities, phases and steps, for the laparoscopic gastric bypass procedure. We propose a multi-task multi-stage temporal convolutional network (MTMS-TCN) along with a multi-task convolutional neural network (CNN) training setup to jointly predict the phases and steps and benefit from their complementarity to better evaluate the execution of the procedure. We evaluate the proposed method on a large video dataset consisting of 40 surgical procedures (Bypass40). RESULTS: We present experimental results from several baseline models for both phase and step recognition on the Bypass40. The proposed MTMS-TCN method outperforms single-task methods in both phase and step recognition by 1-2% in accuracy, precision and recall. Furthermore, for step recognition, MTMS-TCN achieves a superior performance of 3-6% compared to LSTM-based models on all metrics. CONCLUSION: In this work, we present a multi-task multi-stage temporal convolutional network for surgical activity recognition, which shows improved results compared to single-task models on a gastric bypass dataset with multi-level annotations. The proposed method shows that the joint modeling of phases and steps is beneficial to improve the overall recognition of each type of activity.


Assuntos
Derivação Gástrica/métodos , Laparoscopia/métodos , Redes Neurais de Computação , Procedimentos Cirúrgicos Robóticos/métodos , Humanos
4.
Int J Comput Assist Radiol Surg ; 16(8): 1287-1295, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33886045

RESUMO

PURPOSE: The automatic extraction of knowledge about intervention execution from surgical manuals would be of the utmost importance to develop expert surgical systems and assistants. In this work we assess the feasibility of automatically identifying the sentences of a surgical intervention text containing procedural information, a subtask of the broader goal of extracting intervention workflows from surgical manuals. METHODS: We frame the problem as a binary classification task. We first introduce a new public dataset of 1958 sentences from robotic surgery texts, manually annotated as procedural or non-procedural. We then apply different classification methods, from classical machine learning algorithms, to more recent neural-network approaches and classification methods exploiting transformers (e.g., BERT, ClinicalBERT). We also analyze the benefits of applying balancing techniques to the dataset. RESULTS: The architectures based on neural-networks fed with FastText's embeddings and the one based on ClinicalBERT outperform all the tested methods, empirically confirming the feasibility of the task. Adopting balancing techniques does not lead to substantial improvements in classification. CONCLUSION: This is the first work experimenting with machine / deep learning algorithms for automatically identifying procedural sentences in surgical texts. It also introduces the first public dataset that can be used for benchmarking different classification methods for the task.


Assuntos
Algoritmos , Aprendizado de Máquina , Redes Neurais de Computação , Procedimentos Cirúrgicos Robóticos/métodos , Humanos
5.
IEEE Trans Neural Syst Rehabil Eng ; 28(9): 2053-2062, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32746325

RESUMO

Selecting actuators for assistive exoskeletons involves decisions in which designers usually face contrasting requirements. While certain choices may depend on the application context or design philosophy, it is generally desirable to avoid oversizing actuators in order to obtain more lightweight and transparent systems, ultimately promoting the adoption of a given device. In many cases, the torque and power requirements can be relaxed by exploiting the contribution of an elastic element acting in mechanical parallel. This contribution considers one such case and introduces a methodology for the evaluation of different actuator choices resulting from the combination of different motors, reduction gears, and parallel stiffness profiles, helping to match actuator capabilities to the task requirements. Such methodology is based on a graphical tool showing how different design choices affect the actuator as a whole. To illustrate the approach, a back-support exoskeleton for lifting tasks is considered as a case study.


Assuntos
Exoesqueleto Energizado , Desenho de Equipamento , Humanos , Aparelhos Ortopédicos , Torque
6.
Int J Comput Assist Radiol Surg ; 15(8): 1379-1387, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32445126

RESUMO

PURPOSE: Biomechanical simulation of anatomical deformations caused by ultrasound probe pressure is of outstanding importance for several applications, from the testing of robotic acquisition systems to multi-modal image fusion and development of ultrasound training platforms. Different approaches can be exploited for modelling the probe-tissue interaction, each achieving different trade-offs among accuracy, computation time and stability. METHODS: We assess the performances of different strategies based on the finite element method for modelling the interaction between the rigid probe and soft tissues. Probe-tissue contact is modelled using (i) penalty forces, (ii) constraint forces, and (iii) by prescribing the displacement of the mesh surface nodes. These methods are tested in the challenging context of ultrasound scanning of the breast, an organ undergoing large nonlinear deformations during the procedure. RESULTS: The obtained results are evaluated against those of a non-physically based method. While all methods achieve similar accuracy, performance in terms of stability and speed shows high variability, especially for those methods modelling the contacts explicitly. Overall, prescribing surface displacements is the approach with best performances, but it requires prior knowledge of the contact area and probe trajectory. CONCLUSIONS: In this work, we present different strategies for modelling probe-tissue interaction, each able to achieve different compromises among accuracy, speed and stability. The choice of the preferred approach highly depends on the requirements of the specific clinical application. Since the presented methodologies can be applied to describe general tool-tissue interactions, this work can be seen as a reference for researchers seeking the most appropriate strategy to model anatomical deformation induced by the interaction with medical tools.


Assuntos
Modelos Anatômicos , Ultrassonografia/métodos , Fenômenos Biomecânicos , Simulação por Computador , Humanos
7.
Int J Comput Assist Radiol Surg ; 14(8): 1329-1339, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161556

RESUMO

PURPOSE: Although ultrasound (US) images represent the most popular modality for guiding breast biopsy, malignant regions are often missed by sonography, thus preventing accurate lesion localization which is essential for a successful procedure. Biomechanical models can support the localization of suspicious areas identified on a preoperative image during US scanning since they are able to account for anatomical deformations resulting from US probe pressure. We propose a deformation model which relies on position-based dynamics (PBD) approach to predict the displacement of internal targets induced by probe interaction during US acquisition. METHODS: The PBD implementation available in NVIDIA FleX is exploited to create an anatomical model capable of deforming online. Simulation parameters are initialized on a calibration phantom under different levels of probe-induced deformations; then, they are fine-tuned by minimizing the localization error of a US-visible landmark of a realistic breast phantom. The updated model is used to estimate the displacement of other internal lesions due to probe-tissue interaction. RESULTS: The localization error obtained when applying the PBD model remains below 11 mm for all the tumors even for input displacements in the order of 30 mm. This proposed method obtains results aligned with FE models with faster computational performance, suitable for real-time applications. In addition, it outperforms rigid model used to track lesion position in US-guided breast biopsies, at least halving the localization error for all the displacement ranges considered. CONCLUSION: Position-based dynamics approach has proved to be successful in modeling breast tissue deformations during US acquisition. Its stability, accuracy and real-time performance make such model suitable for tracking lesions displacement during US-guided breast biopsy.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mama/diagnóstico por imagem , Biópsia Guiada por Imagem , Imageamento Tridimensional , Ultrassonografia Mamária , Algoritmos , Biópsia , Calibragem , Simulação por Computador , Humanos , Modelos Anatômicos , Posicionamento do Paciente , Imagens de Fantasmas , Robótica , Software
8.
Int J Comput Assist Radiol Surg ; 14(11): 2043, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31250254

RESUMO

The original version of this article unfortunately contained a mistake.

9.
Med Biol Eng Comput ; 57(4): 913-924, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30483912

RESUMO

The modeling of breast deformations is of interest in medical applications such as image-guided biopsy, or image registration for diagnostic purposes. In order to have such information, it is needed to extract the mechanical properties of the tissues. In this work, we propose an iterative technique based on finite element analysis that estimates the elastic modulus of realistic breast phantoms, starting from MRI images acquired in different positions (prone and supine), when deformed only by the gravity force. We validated the method using both a single-modality evaluation in which we simulated the effect of the gravity force to generate four different configurations (prone, supine, lateral, and vertical) and a multi-modality evaluation in which we simulated a series of changes in orientation (prone to supine). Validation is performed, respectively, on surface points and lesions using as ground-truth data from MRI images, and on target lesions inside the breast phantom compared with the actual target segmented from the US image. The use of pre-operative images is limited at the moment to diagnostic purposes. By using our method we can compute patient-specific mechanical properties that allow compensating deformations. Graphical Abstract Workflow of the proposed method and comparative results of the prone-to-supine simulation (red volumes) validated using MRI data (blue volumes).


Assuntos
Simulação por Computador , Elasticidade , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Ultrassonografia , Feminino , Análise de Elementos Finitos , Humanos , Modelos Biológicos , Imagens de Fantasmas
10.
Int J Comput Assist Radiol Surg ; 13(10): 1641-1650, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29869320

RESUMO

PURPOSE: Patient-specific biomedical modeling of the breast is of interest for medical applications such as image registration, image guided procedures and the alignment for biopsy or surgery purposes. The computation of elastic properties is essential to simulate deformations in a realistic way. This study presents an innovative analytical method to compute the elastic modulus and evaluate the elasticity of a breast using magnetic resonance (MRI) images of breast phantoms. METHODS: An analytical method for elasticity computation was developed and subsequently validated on a series of geometric shapes, and on four physical breast phantoms that are supported by a planar frame. This method can compute the elasticity of a shape directly from a set of MRI scans. For comparison, elasticity values were also computed numerically using two different simulation software packages. RESULTS: Application of the different methods on the geometric shapes shows that the analytically derived elongation differs from simulated elongation by less than 9% for cylindrical shapes, and up to 18% for other shapes that are also substantially vertically supported by a planar base. For the four physical breast phantoms, the analytically derived elasticity differs from numeric elasticity by 18% on average, which is in accordance with the difference in elongation estimation for the geometric shapes. The analytic method has shown to be multiple orders of magnitude faster than the numerical methods. CONCLUSION: It can be concluded that the analytical elasticity computation method has good potential to supplement or replace numerical elasticity simulations in gravity-induced deformations, for shapes that are substantially supported by a planar base perpendicular to the gravitational field. The error is manageable, while the calculation procedure takes less than one second as opposed to multiple minutes with numerical methods. The results will be used in the MRI and Ultrasound Robotic Assisted Biopsy (MURAB) project.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Mama/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Imagens de Fantasmas , Procedimentos Cirúrgicos Robóticos , Algoritmos , Biópsia , Calibragem , Simulação por Computador , Diagnóstico por Computador , Elasticidade , Feminino , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Modelos Estatísticos , Reconhecimento Automatizado de Padrão , Ultrassonografia
11.
Analyst ; 143(11): 2596-2603, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29741175

RESUMO

Clinical laboratory-based nucleic acid amplification tests (NAT) play an important role in diagnosing viral infections. However, laboratory infrastructure requirements and their failure to diagnose at the point-of-need (PON) limit their clinical utility in both resource-rich and -limited clinical settings. The development of fast and sensitive PON viral NAT may overcome these limitations. The scalability of silicon microchip manufacturing combined with advances in silicon microfluidics present an opportunity for development of rapid and sensitive PON NAT on silicon microchips. In the present study, we present rapid and sensitive NAT for a number of RNA and DNA viruses on the same silicon microchip platform. We first developed sensitive (4 copies per reaction) one-step RT-qPCR and qPCR assays detecting HCV, HIV, Zika, HPV 16, and HPV 18 on a benchtop real-time PCR instrument. A silicon microchip was designed with an etched 1.3 µL meandering microreactor, integrated aluminum heaters, thermal insulation trenches and microfluidic channels; this chip was used in all on-chip experiments. Melting curve analysis confirmed precise and localized heating of the microreactor. Following minimal optimization of reaction conditions, the bench-scale assays were successfully transferred to 1.3 µL silicon microreactors with reaction times of 25 min with no reduction in sensitivity, reproducibility, or reaction efficiencies. Taken together, these results demonstrate that rapid and sensitive detection of multiple viruses on the same silicon microchip platform is feasible. Further development of this technology, coupled with silicon microchip-based nucleic acid extraction solutions, could potentially shift viral nucleic acid detection and diagnosis from centralized clinical laboratories to the PON.


Assuntos
DNA Viral/análise , Técnicas Analíticas Microfluídicas , RNA Viral/análise , Silício , Técnicas de Amplificação de Ácido Nucleico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Surg Innov ; 25(1): 69-76, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29303068

RESUMO

BACKGROUND: Combining the strengths of surgical robotics and minimally invasive surgery (MIS) holds the potential to revolutionize surgical interventions. The MIS advantages for the patients are obvious, but the use of instrumentation suitable for MIS often translates in limiting the surgeon capabilities (eg, reduction of dexterity and maneuverability and demanding navigation around organs). To overcome these shortcomings, the application of soft robotics technologies and approaches can be beneficial. The use of devices based on soft materials is already demonstrating several advantages in all the exploitation areas where dexterity and safe interaction are needed. In this article, the authors demonstrate that soft robotics can be synergistically used with traditional rigid tools to improve the robotic system capabilities and without affecting the usability of the robotic platform. MATERIALS AND METHODS: A bioinspired soft manipulator equipped with a miniaturized camera has been integrated with the Endoscopic Camera Manipulator arm of the da Vinci Research Kit both from hardware and software viewpoints. Usability of the integrated system has been evaluated with nonexpert users through a standard protocol to highlight difficulties in controlling the soft manipulator. RESULTS AND CONCLUSION: This is the first time that an endoscopic tool based on soft materials has been integrated into a surgical robot. The soft endoscopic camera can be easily operated through the da Vinci Research Kit master console, thus increasing the workspace and the dexterity, and without limiting intuitive and friendly use.


Assuntos
Endoscópios , Endoscopia/educação , Endoscopia/instrumentação , Procedimentos Cirúrgicos Robóticos/educação , Procedimentos Cirúrgicos Robóticos/instrumentação , Adulto , Desenho de Equipamento , Feminino , Humanos , Masculino , Análise e Desempenho de Tarefas , Adulto Jovem
13.
Sensors (Basel) ; 16(11)2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-27854325

RESUMO

In this paper, we present a low-cost, adaptable, and flexible pressure sensor that can be applied as a smart skin over both stiff and deformable media. The sensor can be easily adapted for use in applications related to the fields of robotics, rehabilitation, or costumer electronic devices. In order to remove most of the stiff components that block the flexibility of the sensor, we based the sensing capability on the use of a tomographic technique known as Electrical Impedance Tomography. The technique allows the internal structure of the domain under study to be inferred by reconstructing its conductivity map. By applying the technique to a material that changes its resistivity according to applied forces, it is possible to identify these changes and then localise the area where the force was applied. We tested the system when applied to flat and curved surfaces. For all configurations, we evaluate the artificial skin capabilities to detect forces applied over a single point, over multiple points, and changes in the underlying geometry. The results are all promising, and open the way for the application of such sensors in different robotic contexts where deformability is the key point.


Assuntos
Impedância Elétrica , Tomografia/métodos , Dispositivos Eletrônicos Vestíveis
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 981-984, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28268488

RESUMO

Minimally invasive surgery can be performed with robotic assistance, as evolution of laparoscopic surgery. Robots for assisted surgery are far from being user friendly and require extensive training. To this end, ad-hoc devices and experimental set-ups are needed. The da Vinci system is one of the most diffused surgical robotics technology. The aim of the study was two-fold: i) to propose a neurophysiological measure by which objectively assess the learning progress of the users by means of a simulator of the da Vinci system, and ii) to demonstrate the advantages of cognitive assessment with respect to the standard methodologies for the evaluation of training efficiency.


Assuntos
Laparoscopia/educação , Aprendizagem , Procedimentos Cirúrgicos Robóticos/educação , Adulto , Eletroencefalografia , Humanos , Neurofisiologia , Treinamento por Simulação
15.
Int J Comput Assist Radiol Surg ; 10(6): 843-54, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25930712

RESUMO

PURPOSE: Detection of feature points in medical ultrasound (US) images is the starting point of many clinical tasks, such as segmentation of lesions in pathological areas, estimation of organ deformation, and multimodality image fusion. However, obtaining a reliable feature point localization is a complex task even for an expert radiologist due to the US image characteristics: strong presence of noise, insidious artifacts, and low contrast. In this work, we describe a feature detector based on phase congruency (PhC) combined with a binary pattern descriptor. METHODS: We introduce a feature detector specifically designed for US images and based on PhC analysis. We also introduce a descriptor based on local binary pattern (LBP) operator to improve and simplify the matching between feature points extracted from different images. LBP is not applied directly to the intensity values; instead, it is applied to the PhC output obtained during the detection step to improve robustness to intensity transformation, and the rejection of noise. RESULTS: We tested the proposed approach compared to state-of- the-art methods applied to real US images subject to realistic synthetic transformations. The results of the proposed method, in terms of accuracy and precision, outperform the state-of-the-art approaches that are not designed for US data. CONCLUSIONS: The methods described in this work will enable the development of US-based navigation system, which supports automatic feature point detection and matching from US images acquired at different times during the procedure.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Ultrassonografia/métodos , Algoritmos , Humanos
16.
Bioinspir Biomim ; 8(2): 026001, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23462257

RESUMO

In underwater locomotion, extracting meaningful information from local flows is as desirable as it is challenging, due to complex fluid-structure interaction. Sensing and motion are tightly interconnected; hydrodynamic signals generated by the external stimuli are modified by the self-generated flow signals. Given that very little is known about self-generated signals, we used onboard pressure sensors to measure the pressure profiles over the head of a fusiform-shape craft while moving forward and backward harmonically. From these measurements we obtained a second-order polynomial model which incorporates the velocity and acceleration of the craft to estimate the surface pressure within the swimming range up to one body length/second (L s(-1)). The analysis of the model reveals valuable insights into the temporal and spatial changes of the pressure intensity as a function of craft's velocity. At low swimming velocities (<0.2 L s(-1)) the pressure signals are more sensitive to the acceleration of the craft than its velocity. However, the inertial effects gradually become less important as the velocity increases. The sensors on the front part of the craft are more sensitive to its movements than the sensors on the sides. With respect to the hydrostatic pressure measured in still water, the pressure detected by the foremost sensor reaches values up to 300 Pa at 1 L s(-1) swimming velocity, whereas the pressure difference between the foremost sensor and the next one is less than 50 Pa. Our results suggest that distributed pressure sensing can be used in a bimodal sensing strategy. The first mode detects external hydrodynamic events taking place around the craft, which requires minimal sensitivity to the self-motion of the craft. This can be accomplished by moving slowly with a constant velocity and by analyzing the pressure gradient as opposed to absolute pressure recordings. The second mode monitors the self-motion of the craft. It is shown here that distributed pressure sensing can be used as a speedometer to measure the craft's velocity.


Assuntos
Biomimética/instrumentação , Hidrodinâmica , Modelos Teóricos , Reologia/instrumentação , Robótica/instrumentação , Navios/instrumentação , Transdutores de Pressão , Biomimética/métodos , Simulação por Computador , Desenho Assistido por Computador , Retroalimentação , Reologia/métodos , Robótica/métodos , Navios/métodos
17.
Bioinspir Biomim ; 7(3): 036004, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22498729

RESUMO

With the overall goal being a better understanding of the sensing environment from the local perspective of a situated agent, we studied uniform flows and Kármán vortex streets in a frame of reference relevant to a fish or swimming robot. We visualized each flow regime with digital particle image velocimetry and then took local measurements using a rigid body with laterally distributed parallel pressure sensor arrays. Time and frequency domain methods were used to characterize hydrodynamically relevant scenarios in steady and unsteady flows for control applications. Here we report that a distributed pressure sensing mechanism has the capability to discriminate Kármán vortex streets from uniform flows, and determine the orientation and position of the platform with respect to the incoming flow and the centre axis of the Kármán vortex street. It also enables the computation of hydrodynamic features which may be relevant for a robot while interacting with the flow, such as vortex shedding frequency, vortex travelling speed and downstream distance between vortices. A Kármán vortex street was distinguished in this study from uniform flows by analysing the magnitude of fluctuations present in the sensor measurements and the number of sensors detecting the same dominant frequency. In the Kármán vortex street the turbulence intensity was 30% higher than that in the uniform flow and the sensors collectively sensed the vortex shedding frequency as the dominant frequency. The position and orientation of the sensor platform were determined via a comparative analysis between laterally distributed sensor arrays; the vortex travelling speed was estimated via a cross-correlation analysis among the sensors.


Assuntos
Biomimética/instrumentação , Peixes/fisiologia , Reologia/instrumentação , Órgãos dos Sentidos/fisiologia , Natação/fisiologia , Transdutores de Pressão , Movimentos da Água , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Pressão
18.
J Minim Invasive Gynecol ; 18(6): 705-15, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22024259

RESUMO

To assess differences between laparoscopic hysterectomy performed with or without robot-assistance, we performed metaanalyses of 5 key indices strongly associated with societal and hospital costs, patient safety, and intervention quality. The 5 indexes included estimated blood loss (EBL), operative time, number of conversions to laparotomy, hospital length of stay (LOS), and number of postoperative complications. A search of PubMed, Medline, Embase, and Science citation index online databases yielded a total of 605 studies. After a systematic review, we proceeded with meta-analysis of 14 articles for EBL, with a summary effect of -0.61 (95% confidence interval [CI], -42.42 to 46.20); 20 for operative time, with a summary effect of 0.66 (95% CI, -15.72 to 17.04); 17 for LOS, with a summary effect of -0.43 (95% CI, -0.68 to -0.17); 15 for conversion to laparotomy (odds ratio, 0.50; 95% CI, 0.31 to 0.79 with a random model); and 14 for postoperative complications (odds ratio, 0.69; 95% CI, 0.43 to 1.09 with a random model). In conclusion, compared with traditional laparoscopic hysterectomy, robot-assisted laparoscopic hysterectomy was associated with shorter LOS and fewer postoperative complications and conversions to laparotomy; there were no differences in EBL and operative time. These results confirm that robot-assisted laparoscopy has less deletorious effect on hospital, society, and patient stress and leads to better intervention quality.


Assuntos
Histerectomia/métodos , Laparoscopia/métodos , Robótica , Cirurgia Assistida por Computador/métodos , Feminino , Humanos , Histerectomia/instrumentação , Resultado do Tratamento
19.
Bioinspir Biomim ; 6(3): 036001, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21670492

RESUMO

In this work, we focus on biomimetic lateral line sensing in Kármán vortex streets. After generating a Kármán street in a controlled environment, we examine the hydrodynamic images obtained with digital particle image velocimetry (DPIV). On the grounds that positioning in the flow and interaction with the vortices govern bio-inspired underwater locomotion, we inspect the fluid in the swimming robot frame of reference. We spatially subsample the flow field obtained using DPIV to emulate the local flow around the body. In particular, we look at various sensor configurations in order to reliably identify the vortex shedding frequency, wake wavelength and downstream flow speed. Moreover, we propose methods that differentiate between being in and out of the Kármán street with >70% accuracy, distinguish right from left with respect to Kármán vortex street centreline (>80%) and highlight when the sensor system enters the vortex formation zone (>75%). Finally, we present a method that estimates the relative position of a sensor array with respect to the vortex formation point within 15% error margin.


Assuntos
Materiais Biomiméticos , Biomimética/instrumentação , Biomimética/métodos , Peixes/fisiologia , Sistema da Linha Lateral/fisiologia , Reologia/instrumentação , Reologia/métodos , Algoritmos , Animais , Desenho de Equipamento , Análise de Falha de Equipamento
20.
Artigo em Inglês | MEDLINE | ID: mdl-22256116

RESUMO

A cost-effective, miniaturized and biocompatible packaging method for medical devices is proposed, resulting in a small, soft and comfortable implantable package. Towards this end, the barrier materials and fabrication process for the individual die encapsulation are largely explored. We demonstrate that various common clean room materials are good candidates for preventing metal leaching into body. In accelerated tests at higher temperature, several conductive barrier materials are damaged by the test bio-fluid, suggesting insufficient resistance to body fluids in long term. Covering electrodes by noble metals will solve this problem. For metallization, noble metals as Pt are best candidates. CoO calculations showed that selective plating of Pt is more cost-effective than sputtering. To reduce the cost of a sputter process, Pt recycling is very important.


Assuntos
Materiais Biocompatíveis/economia , Eletrônica Médica/instrumentação , Miniaturização/instrumentação , Embalagem de Produtos/economia , Embalagem de Produtos/métodos , Animais , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Análise Custo-Benefício , Difusão/efeitos dos fármacos , Camundongos , Microscopia Eletrônica de Varredura , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Platina/farmacologia
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