1,720,959 research outputs found
A Novel Childbirth Simulator for Real-Time Monitoring of Fetal Head During the Active Phase of the Labor
No full textA correct evaluation of the fetus progress into the birth canal during labor is often a complicated task, but it is of fundamental importance for a proper delivery management. Indeed, incorrect assessment of fetal presentation, position and station could lead to severe complications for both the fetus and the mother. Currently, fetus progress assessment during the delivery phase is still performed in the same way of last centuries, namely with a manual vaginal exploration assessed only using two fingers (index and medium fingers). This evaluation is therefore strongly subjective and dependent on clinical experience of the medical doctor; thus, reproducibility is very limited. In this framework, simulation-based training is a valuable instrument for obstetrics and gynecologists learning process, thus for evaluating and improving their abilities. In this work, we introduce a novel integrated childbirth platform which offers a real-time monitoring of fetal head during the active phase of labor. A real-time evaluation of fetal head presentation, position and station is provided, along with a 3D virtual visualization of the childbirth simulation. This kind of platform was conceived as a valid instrument for gynecological teaching and training. Preliminary results demonstrated its usefulness as an instrument for training in obstetrics and gynecology
High-Intensity Focused Ultrasound Surgery Based on KUKA Robot: A Computer-Assisted Platform for Noninvasive Surgical Treatments on Static and Moving Organs
No full textHigh-intensity focused ultrasound surgery based on a KUKA robot (HIFUSK) can address unmet clinical needs in the treatment of pathological tissues, such as cancerous tissues. HIFUSK is the marriage of two technologies: robotics and focused ultrasound (FUS). Such a combination results in a surgical treatment that is precise and noninvasive (no incisions, no anesthesia, and no ionizing energy) thanks to robotics and FUS, respectively. Robotic control and machine learning algorithms ensure safety even in case of target motions during therapy. The platform has been validated in dry lab/ex vivo scenarios, and it was preliminarily tested in terms of safety and efficacy during an in vivo test on a large animal model
Acoustic Coupling Quantification in Ultrasound-Guided Focused Ultrasound Surgery: Simulation-Based Evaluation and Experimental Feasibility Study
No full textAdequate acoustic coupling between the therapeutic transducer and the patient's body is essential for safe and efficient focused ultrasound surgery (FUS). There is currently no quantitative method for acoustic coupling verification in ultrasound-guided FUS. In this work, a quantitative method was developed and a related metric was introduced: the acoustic coupling coefficient. This metric associates the adequacy of the acoustic coupling with the reflected signals recorded through an imaging probe during a low-energy sonication. The acoustic coupling issue was simulated in silico and validated through in vitro tests. Our results indicated a sigmoidal behavior of the introduced metric as the contact surface between the coupling system and the patient's skin increases. The proposed method could be a safety-check criterion for verifying the adequacy of the acoustic coupling before starting the FUS treatment, thus ensuring efficient energy transmission to the target and preventing damage to both the patient and the instrumentation
An Easy and User Independent Augmented Reality Based Navigation System for Radiation-Free Interventional Procedure
Full text linkDespite offering numerous advantages, percutaneous treatments in interventional cardiology still present several limitations, including the recurrent use of fluoroscopy to track the route of the catheter during the intervention. In this study we propose an augmented reality (AR)-based navigation system for radiation-free interventional procedures using electromagnetic (EM) sensors. A customized tool embedding an EM sensor and a QRcode (automatically tracked in AR) was designed to perform the registration procedure. The accuracy of the system was assessed asking the user to evaluate the distance between the real position of the sensor and its holographic counterpart by means of a holographic measurement tool. Variability between intra-and inter-operator accuracy was assessed, each one performing 10 evaluation tests. Results showed a mean error of 2.70 ± 0.36 mm and 2.68 ± 0.79 mm for the intra-and inter-operator tests, respectively. To the best of our knowledge this is the first study that proposes a user independent procedure for calibrating an AR device with an EM system presenting a quantitative evaluation between intra-and inter-operators
A Pilot Study for a Quantitative Evaluation of Acoustic Coupling in US-guided Focused Ultrasound Surgery
No full textIn Ultrasound-guided High Intensity Focused Ultrasound (USgHIFU) surgery, the verification of the acoustic coupling correctness between the HIFU transducer and the patient’s body is afundamental stepfor an efficient and safe therapy. Nowadays, cliniciansperformthis checkby qualitative inspectingUltrasoundimages. The aim of this study is the introduction ofanobjectiveindex toquantitively evaluate the couplingon the base ofthe radiofrequency echo signalsacquired during a low-energy HIFU shot. The experimental session involved atissue mimicking phantomandaroboticsystem composed by a HIFU therapeutic transducer and a 2D confocal Ultrasound probe.15 different coupling conditions between the phantom and the transducerwere tested:in each of them, the maximum absolute value of theFourier Transform of theecho signals was computedand employed to determine an Acoustic Coupling (AC) coefficient.Thismetricsshowedasigmoidal trend between ACcoefficient and couplingincrease. This curve can be employed as acalibration tool to quantitatively assess the correctness of the therapeutic set-up before starting the HIFU treatment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A Reusable Thermochromic Phantom for Testing High Intensity Focused Ultrasound Technologies
No full text: High Intensity Focused Ultrasound (HIFU) surgery is a promising technology for the treatment of several pathologies, including cancer. Testing is a fundamental step for verifying treatment efficacy and safety. Ex-vivo tissues represent the most common solution for replicating the properties of human tissues in the HIFU operative scenario. However, they constitute an avoidable waste of resources. Thus, tissue mimicking phantoms have been investigated as a more sustainable and reliable alternative. In this scenario, we proposed a reusable silicone-based thermochromic phantom. It is cost-effective and can be rapidly fabricated. The acoustic, mechanical, and thermal characterization of the phantom are reported. The phantom usability was evaluated with a HIFU robotic platform. 18 different working conditions were tested by varying both sonication power and duration. Temperature and simulated lesions' size were quantified for all testing conditions. An accordance between temperature and lesion dimension trend over time was found. The proposed phantom results a valid alternative to ex-vivo tissues, especially in the early stages of developing novel HIFU treatment paradigms
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