bipolar electrode
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2022 ◽  
Vol 12 (1) ◽  
pp. 86
Author(s):  
Mevlüt Yalaz ◽  
Nicholas Maling ◽  
Günther Deuschl ◽  
León M. Juárez-Paz ◽  
Markus Butz ◽  
...  

Background: Current approaches to detect the positions and orientations of directional deep-brain stimulation (DBS) electrodes rely on radiative imaging data. In this study, we aim to present an improved version of a radiation-free method for magnetic detection of the position and the orientation (MaDoPO) of directional electrodes based on a series of magnetoencephalography (MEG) measurements and a possible future solution for optimized results using emerging on-scalp MEG systems. Methods: A directional DBS system was positioned into a realistic head–torso phantom and placed in the MEG scanner. A total of 24 measurements of 180 s each were performed with different predefined electrode configurations. Finite element modeling and model fitting were used to determine the position and orientation of the electrode in the phantom. Related measurements were fitted simultaneously, constraining solutions to the a priori known geometry of the electrode. Results were compared with the results of the high-quality CT imaging of the phantom. Results: The accuracy in electrode localization and orientation detection depended on the number of combined measurements. The localization error was minimized to 2.02 mm by considering six measurements with different non-directional bipolar electrode configurations. Another six measurements with directional bipolar stimulations minimized the orientation error to 4°. These values are mainly limited due to the spatial resolution of the MEG. Moreover, accuracies were investigated as a function of measurement time, number of sensors, and measurement direction of the sensors in order to define an optimized MEG device for this application. Conclusion: Although MEG introduces inaccuracies in the detection of the position and orientation of the electrode, these can be accepted when evaluating the benefits of a radiation-free method. Inaccuracies can be further reduced by the use of on-scalp MEG sensor arrays, which may find their way into clinics in the foreseeable future.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryo Takeuchi ◽  
Hidetaka Asoh

AbstractThe effects of the size and position of an aluminum bipolar electrode (BPE) on the uniformity of formation of anodic porous alumina in an alternating current electric field were investigated. Anodized specimens were dyed, and the resistance was measured after the specimens were anodized again. Phenomena observed during film formation indicated that the BPEs had unique potential distributions that strongly depended on their length and width. The color variations and electrical resistance of the BPEs were symmetrical and varied from the centers of the BPEs to their ends. When multiple BPEs were processed at the same time, their position in the non-uniform electric field was demonstrated to be an important factor for controlling the uniformity of film formation. The best results were obtained when the BPE was placed at the center of the defined space.


2021 ◽  
Vol MA2021-02 (57) ◽  
pp. 1818-1818
Author(s):  
Ivan Mondaca Medina ◽  
Ryan Freedman ◽  
Jeronimo Miranda ◽  
Nick Humphrey ◽  
Rowan Kinney ◽  
...  

2021 ◽  
Vol MA2021-02 (55) ◽  
pp. 1609-1609
Author(s):  
David Probst ◽  
Inyoung Lee ◽  
Jeffrey E Dick ◽  
Koji Sode
Keyword(s):  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Noel Pérez ◽  
Karl Muffly ◽  
Stephen E. Saddow

Abstract Background Renal denervation with radiofrequency ablation has become an accepted treatment for drug-resistant hypertension. However, there is a continuing need to develop new catheters for high-accuracy, targeted ablation. We therefore developed a radiofrequency bipolar electrode for controlled, targeted ablation through Joule heating induction between 60 and 100 °C. The bipolar design can easily be assembled into a basket catheter for deployment inside the renal artery. Methods Finite element modeling was used to determine the optimum catheter design to deliver a minimum ablation zone of 4 mm (W) × 10 mm (L) × 4 mm (H) within 60 s with a 500 kHz, 60 Vp-p signal, and 3 W maximum. The in silico model was validated with in vitro experiments using a thermochromic phantom tissue prepared with polyacrylamide gel and a thermochromic ink additive that permanently changes from pink to magenta when heated over 60 °C. Results The in vitro ablation zone closely matched the size and shape of the simulated area. The new electrode design directs the current density towards the artery walls and tissue, reducing unwanted blood temperature increases by focusing energy on the ablation zone. In contrast, the basket catheter design does not block renal flow during renal denervation. Conclusions This computational model of radiofrequency ablation can be used to estimate renal artery ablation zones for highly targeted renal denervation in patients with resistant hypertension. Furthermore, this innovative catheter has short ablation times and is one of the lowest power requirements of existing designs to perform the ablation.


2021 ◽  
Author(s):  
Dawid Kałuża ◽  
Katarzyna Węgrzyn ◽  
Brian Kaczmarczyk ◽  
Marianna Gniadek ◽  
Krzysztof Maksymiuk ◽  
...  

Nano Energy ◽  
2021 ◽  
pp. 106551
Author(s):  
Gaoqiang Yang ◽  
Zhiqiang Xie ◽  
Shule Yu ◽  
Kui Li ◽  
Yifan Li ◽  
...  
Keyword(s):  

Author(s):  
Yue Hu ◽  
Liang Zhu ◽  
Xuecui Mei ◽  
Jinsen Liu ◽  
Zhongping Yao ◽  
...  

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