Microsecond laser ablation of thrombus and gelatin under clear liquids: Contact versus noncontact

Shangguan, HanQun; Casperson, Lee W.; Prahl, Scott A.

doi:10.1109/2944.577304

Cited by 13 publications

(13 citation statements)

References 21 publications

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“…The formation of blood clots is subject to the presence or absence of hun-dreds of chemical factors, as well as physical factors like pressure, flow, and temperature [16]. We found that blood collected from different pigs and cured for equal times at equal temperatures did not always yield similar strength clots [17]. Finally, some investigators are actively working on creating physical models of clot that more accurately resemble clot [18].…”

Section: Sample Preparationmentioning

confidence: 95%

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

et al. 1998

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Background and Objective: Current techniques for laser thrombolysis are limited because they can not completely clear thrombotic occlusions in arteries, typically leaving residual thrombus on the walls of the artery. The objective of this study was to investigate the possibility of using photomechanical drug delivery to enhance laser thrombolysis by delivering drugs into mural thrombus during laser thrombolysis. Study Design/Materials and Methods: Three experimental protocols were performed in vitro to quantitatively compare the effectiveness of thrombolysis by 1) constant infusion of drug, 2) laser thrombolysis, and 3) photomechanical drug delivery. A fiber‐optic flushing catheter delivered drug (a solution of 1 μm fluorescent microspheres) and light ( a 1 μs pulsed dye laser) into a gelatin‐based thrombus model. The process of laser‐thrombus interaction was visualized using flash photography and the laser‐induced pressure waves were measured using an acoustic transducer. Results Lumen sizes generated by mechanically manipulating the catheter through the thrombus were smaller than those generated by laser ablation. The microspheres could be driven several hundred microns into the mural thrombus. Conclusion Photomechanical drug delivery has potential for enhancement of laser thrombolysis. Two mechanisms seem to be involved in photomechanical drug delivery: 1) mural deposition of the drug at the ablation site and 2) increased exposure of the thrombus surface area to the drug. Lasers Surg. Med. 23:151–160, 1998. © 1998 Wiley‐Liss, Inc.

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Section: Sample Preparationmentioning

confidence: 95%

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

et al. 1998

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“…The higher bubble expansion pressures result in larger lumen areas , which agrees with an ablation efficiency study. 8 However, the penetration depth of the spheres in gelatin samples was not simply proportional to the laser energy. The penetration increased at least before the laser energy reached 50 mJ, and started deceasing somewhere between 50-70 mJ.…”

Section: Discussionmentioning

confidence: 99%

Penetration of fluorescent particles in gelatin during laser thrombolysis

et al. 1997

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The use of pulsed laser energy to clear arteries obstructed by thrombus (blood clot) and plaque has emerged as a promising method for the treatment of cardiovascular diseases such as myocardial infarction and stroke. Current techniques for laser thrombolysis are limited because they cannot completely clear the clot in arteries, especially where a large volume clot is presented. Mural clot is a potent stimulus for reocclusion. We suggest that the combination of laser thrombolysis and localized intramural delivery of clot-dissolving drugs during the procedure may be a solution to this limitation.Ninety pulses of 30-70 mJ were delivered onto gelatin-based thrombus model with a flushing catheter. A solution of 1 µm fluorescent particles as a drug model was injected at a rate of 4mL/min in coincidence with the laser delivery. The controls were performed by injecting drug after laser thrombolysis. We measured the penetration of the particles in gelatin and the sizes of the lumen and stained areas. The results of this study demonstrated the possibility of enhancing laser thrombolysis by delivering drugs into thrombus. It was found that the particles could be driven several hundred micron in gelatin, and the lumen areas would be increased up to 25% if the areas were dissolved by the drugs.

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“…During bubble collapse liquid jets are formed and shockwaves are emitted, which carries away the excess energy into the surrounding liquid (Lauterborn & Hentschel, 1985). Laser generated bubbles are of special interest as it assists in tissue cutting, removal of thrombus from obstructed arteries, expulsion of bile duct stones via fragmentation and lithotripsy (Venugopalan et al, 2002;Shangguan et al, 1996;Carroll et al, 1993;Zhong et al, 1997). However, the accompanying shockwaves and jets, induces cavitation erosion that are not always desirable as it results in dilation and collateral damage of adjacent tissues, hence laser assisted microsurgery requires well controlled and optimized experimental conditions (Jansen et al, 1998;Vogel et al, 1990Vogel et al, , 1996b.…”

Section: Introductionmentioning

confidence: 99%

Transient evolution of multiple bubbles in laser induced breakdown in water

Nath

Khare

2010

Laser Part. Beams

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Pulsed laser induced plasma in water produces multiple bubbles with the passage of laser pulse. Shadowgraphy and beam deflection set-up is used to study the temporal and spatial evolution of these bubbles as a function of distance from the laser focus. The formation of multiple bubbles, bubble coalescence, and their effect onto cavity dynamics is reported. Bubble radius and the corresponding velocities from shadowgraphy is used to calculate the maximum gas pressure inside the bubble using Neppiras model. The maximum pressure inside the cavity is found to be 0.4 MPa at the laser focus.

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Microsecond laser ablation of thrombus and gelatin under clear liquids: Contact versus noncontact

Cited by 13 publications

References 21 publications

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

Enhanced laser thrombolysis with photomechanical drug delivery: An in vitro study

Penetration of fluorescent particles in gelatin during laser thrombolysis

Transient evolution of multiple bubbles in laser induced breakdown in water

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