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176 results on '"Palanker, Daniel V."'

3. Femtosecond laser capsulotomy

Author

Friedman, Neil J., Palanker, Daniel V., Schuele, Georg, Andersen, Dan, Marcellino, George, Seibel, Barry S., Batlle, Juan, Feliz, Rafael, Talamo, Jonathan H., Blumenkranz, Mark S., and Culbertson, William W.

Published
2011
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7. Electrosurgery with cellular precision

Author

Palanker, Daniel V., Vankov, Alexander, and Huie, Philip

Subjects
Cavitation -- Control, Electrosurgery -- Technology application, Ablation (Vaporization technology) -- Methods, Biomedical engineering -- Research, Technology application, Biological sciences, Business, Computers, Health care industry
Abstract

Electrosurgery, one of the most-often used surgical tools, is a robust but somewhat crude technology that has changed surprisingly little since its invention almost a century ago. Continuous radiofrequency is still used for tissue cutting, with thermal damage extending to hundreds of micrometers. In contrast, lasers developed 70 years later, have been constantly perfected, and the laser-tissue interactions explored in great detail, which has allowed tissue ablation with cellular precision in many laser applications. We discuss mechanisms of tissue damage by electric field, and demonstrate that electrosurgery with properly optimized waveforms and microelectrodes can rival many advanced lasers. Pulsed electric waveforms with burst durations ranging from 10 to 100 [micro]s applied via insulated planar electrodes with 12 [micro]m wide exposed edges produced plasma-mediated dissection of tissues with the collateral damage zone ranging from 2 to 10 [micro]m. Length of the electrodes can vary from micrometers to centimeters and all types of soft tissues--from membranes to cartilage and skin could be dissected in liquid medium and in a dry field. This technology may allow for major improvements in outcomes of the current surgical procedures and development of much more refined surgical techniques. Index Terms--Cavitation, electrosurgery, electroporation, pulsed ablation, thermal confinement.

Published
2008

8. Image processing for a high-resolution optoelectronic retinal prosthesis

Author

Asher, Alon, Segal, William A., Baccus, Stephen A., Yaroslavsky, Leonid P., and Palanker, Daniel V.

Subjects
Artificial vision -- Design and construction, Artificial vision -- Research, Image processing -- Analysis, Biological sciences, Business, Computers, Health care industry
Abstract

In an effort to restore visual perception in retinal diseases such as age-related macular degeneration or retinitis pigmentosa, a design was recently presented for a high-resolution optoelectronic retinal prosthesis having thousands of electrodes. This system requires real-time image processing fast enough to convert a video stream of images into electrical stimulus patterns that can be properly interpreted by the brain. Here, we present image-processing and tracking algorithms for a subretinal implant designed to stimulate the second neuron in the visual pathway, bypassing the degenerated first synaptic layer. For this task, we have developed and implemented: 1) A tracking algorithm that determines the implant's position in each frame. 2) Image cropping outside of the implant boundaries. 3) A geometrical transformation that distorts the image appropriate to the geometry of the fovea. 4) Spatio-temporal image filtering to reproduce the visual processing normally occurring in photoceptors and at the photoreceptor-bipolar cell synapse. 5) Conversion of the filtered visual information into a pattern of electrical current. Methods to accelerate real-time transformations include the exploitation of data redundancy in the time domain, and the use of precomputed lookup tables that are adjustable to retinal physiology and allow flexible control of stimulation parameters. A software implementation of these algorithms processes natural visual scenes with sufficient speed for real-time operation. This computationally efficient algorithm resembles, in some aspects, biological strategies of efficient coding in the retina and could provide a refresh rate higher than fifty frames per second on our system. Index Terms--Biomedical image processing, macular degeneration, retinal prosthesis, retinitis pigmentosa.

Published
2007

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