scholarly journals Ultrasound-guided navigation of a magnetic microrobot using acoustic phase analysis

2021 ◽  
Author(s):  
Stefano Pane ◽  
Veronica Iacovacci ◽  
Mohammad Hasan Dad Ansari ◽  
Arianna Menciassi
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Average Error ◽  
Low Contrast ◽  
Loop Control ◽  
Non Invasive ◽  
Fine Control ◽  
Real Time Visualization ◽  
Acoustic Phase

Abstract Microrobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for closed-loop MR control, we propose a US contrast enhancement mechanism for MR visualization in heterogeneous and dynamic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for closed-loop control of medical MRs in-vivo.

scholarly journals Dynamic tracking of a magnetic micro-roller using ultrasound phase analysis

2021 ◽  
Author(s):  
Stefano Pane ◽  
Veronica Iacovacci ◽  
Mohammad Hasan Dad Ansari ◽  
Arianna Menciassi
Keyword(s):  
Real Time ◽  
Average Error ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Non Invasive ◽  
Dynamic Tracking ◽  
Fine Control ◽  
Real Time Visualization ◽  
Acoustic Phase

Abstract Microrobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for monitoring and tracking MRs, we propose a US contrast enhancement mechanism for MR visualization in echogenic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for monitoring and tracking biomedical MRs in-vivo.

scholarly journals Dynamic tracking of a magnetic micro-roller using ultrasound phase analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefano Pane ◽  
Veronica Iacovacci ◽  
Mohammad Hasan Dad Ansari ◽  
Arianna Menciassi
Keyword(s):  
Real Time ◽  
Average Error ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Non Invasive ◽  
Dynamic Tracking ◽  
Fine Control ◽  
Real Time Visualization ◽  
Acoustic Phase

AbstractMicrorobots (MRs) have attracted significant interest for their potentialities in diagnosis and non-invasive intervention in hard-to-reach body areas. Fine control of biomedical MRs requires real-time feedback on their position and configuration. Ultrasound (US) imaging stands as a mature and advantageous technology for MRs tracking, but it suffers from disturbances due to low contrast resolution. To overcome these limitations and make US imaging suitable for monitoring and tracking MRs, we propose a US contrast enhancement mechanism for MR visualization in echogenic backgrounds (e.g., tissue). Our technique exploits the specific acoustic phase modulation produced by the MR characteristic motions. By applying this principle, we performed real-time visualization and position tracking of a magnetic MR rolling on a lumen boundary, both in static flow and opposing flow conditions, with an average error of 0.25 body-lengths. Overall, the reported results unveil countless possibilities to exploit the proposed approach as a robust feedback strategy for monitoring and tracking biomedical MRs in-vivo.

scholarly journals Near Infra-Red Labelling and Tracking of Transplanted Corneal Endothelial Graft

2021 ◽  
Author(s):  
Maninder Bhogal ◽  
Heng-Pei Ang ◽  
Shu-Jun Lin ◽  
Lwin Chan ◽  
Khadijah Adnan ◽  
...  
Keyword(s):  
Real Time ◽  
Corneal Transplantation ◽  
Specular Microscopy ◽  
Post Transplantation ◽  
In Vivo Evaluation ◽  
Non Invasive ◽  
Real Time Visualization ◽  
Donor Graft

Abstract Following corneal transplantation, there is an initial decline in corneal endothelial cells (CECs) following graft preparation and surgery. Monitoring post-transplantation is only possible months after surgery by specular microscopy, which has a limited field of view. We have developed a labelling approach using 1,1’-dioctadecyl-3,3,3’,3’-tetramethylindotricarbocyanine iodide (DIR) dye solution, that enabled tracking of labelled CECs in vivo for at least one month. Initial in vitro optimization of dye concentration, cellular toxicity and real-time cell migration was assessed using propagated primary CECs. Subsequent in vivo evaluation of cellular labelling was assessed within a rabbit wound healing model. Finally, real-time visualization of human cadaver donor tissue incubated in DIR transplanted into rabbits was achieved using the Heidelberg Spectralis. Results revealed detectable fluorescence increased with concentration to a plateau of 100µg/ml, with no toxicity of CECs at any concentration evaluated. DIR-labelled CECs were detectable in vivo upto 1 month, and transplanted labelled donor graft could be visualized and were trackable in vivo. Acute endothelial rejection in 1 rabbit was evidenced by detectable DIR positive cells within the anterior chamber. DIR imaging allowed for detailed imaging of the transplanted corneal endothelium, and enabled non-invasive observation of the corneal endothelial morphology following transplantation.

A Playbook(trademark) for Real-Time, Closed-Loop Control

2005 ◽  
Author(s):  
Harry Funk ◽  
Robert Goldman ◽  
Christopher Miller ◽  
John Meisner ◽  
Peggy Wu
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control

scholarly journals Evaluation of Optimal Vibrotactile Feedback for Force-Controlled Upper Limb Myoelectric Prostheses

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5209 ◽  
Author(s):  
Andrea Gonzalez-Rodriguez ◽  
Jose L. Ramon ◽  
Vicente Morell ◽  
Gabriel J. Garcia ◽  
Jorge Pomares ◽  
...  
Keyword(s):  
Real Time ◽  
Upper Limb ◽  
Closed Loop ◽  
Fine Tuning ◽  
Vibrotactile Feedback ◽  
Loop Control ◽  
Myoelectric Prostheses ◽  
Amplitude Level ◽  
Real Time Application ◽  
Selection Of

The main goal of this study is to evaluate how to optimally select the best vibrotactile pattern to be used in a closed loop control of upper limb myoelectric prostheses as a feedback of the exerted force. To that end, we assessed both the selection of actuation patterns and the effects of the selection of frequency and amplitude parameters to discriminate between different feedback levels. A single vibrotactile actuator has been used to deliver the vibrations to subjects participating in the experiments. The results show no difference between pattern shapes in terms of feedback perception. Similarly, changes in amplitude level do not reflect significant improvement compared to changes in frequency. However, decreasing the number of feedback levels increases the accuracy of feedback perception and subject-specific variations are high for particular participants, showing that a fine-tuning of the parameters is necessary in a real-time application to upper limb prosthetics. In future works, the effects of training, location, and number of actuators will be assessed. This optimized selection will be tested in a real-time proportional myocontrol of a prosthetic hand.

scholarly journals Closed-loop control system for well-defined oxygen supply in micro-physiological systems

2017 ◽  
Vol 3 (2) ◽  
pp. 363-366
Author(s):  
Tobias Steege ◽  
Mathias Busek ◽  
Stefan Grünzner ◽  
Andrés Fabían Lasagni ◽  
Frank Sonntag
Keyword(s):  
Control System ◽  
Oxygen Supply ◽  
Closed Loop ◽  
Microfluidic System ◽  
Closed Loop Control ◽  
Loop Control ◽  
Cell Vitality ◽  
Closed Loop Control System ◽  
Loop Control System

AbstractTo improve cell vitality, sufficient oxygen supply is an important factor. A deficiency in oxygen is called Hypoxia and can influence for example tumor growth or inflammatory processes. Hypoxia assays are usually performed with the help of animal or static human cell culture models. The main disadvantage of these methods is that the results are hardly transferable to the human physiology. Microfluidic 3D cell cultivation systems for perfused hypoxia assays may overcome this issue since they can mimic the in-vivo situation in the human body much better. Such a Hypoxia-on-a-Chip system was recently developed. The chip system consists of several individually laser-structured layers which are bonded using a hot press or chemical treatment. Oxygen sensing spots are integrated into the system which can be monitored continuously with an optical sensor by means of fluorescence lifetime detection.Hereby presented is the developed hard- and software requiered to control the oxygen content within this microfluidic system. This system forms a closed-loop control system which is parameterized and evaluated.

scholarly journals Non-invasive, real-time reporting drug release in vitro and in vivo

2015 ◽  
Vol 51 (32) ◽  
pp. 6948-6951 ◽  
Author(s):  
Yanfeng Zhang ◽  
Qian Yin ◽  
Jonathan Yen ◽  
Joanne Li ◽  
Hanze Ying ◽  
...  
Keyword(s):  
Drug Release ◽  
Real Time ◽  
Near Infrared ◽  
Reporting System ◽  
Real Time Monitoring ◽  
Near Infrared Fluorescence ◽  
Non Invasive ◽  
Fluorescence Dye

Anin vitroandin vivodrug-reporting system is developed for real-time monitoring of drug release via the analysis of the concurrently released near-infrared fluorescence dye.

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