Cooled-Tip Diode Laser Catheter for Improved Catheter Ablation of Ventricular Tachycardia

Snakard, Eileen P.; Miller, Matthew W.; Berridge, Brian R.; Gowda, Ashok; McNichols, Roger J.; Tw, Fossum

doi:10.1080/089419301753435729

Cited by 7 publications

(2 citation statements)

References 31 publications

(45 reference statements)

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“…This dark field is a closed region surrounded by highintensity light. [1,2] Bottle beams have a wide range of applications in optical tweezers, [3,4] laser catheters, [5] and optical micromanipulation. [6] In particular, when a bottle beam is applied to optical tweezers, it can stably capture and manipulate microscopic particles.…”

Section: Introductionmentioning

confidence: 99%

Multiple bottle beams based on metasurface optical field modulation and their capture of multiple atoms

Xichun

Wensheng

et al. 2022

Chinese Phys. B

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Compared to conventional devices, metasurface offer the advantages of lightweight, planarization and tuning flexibility. It provides a new way to integrate and miniaturize optical systems. In this paper, a metasurface capable of generating multiple bottle beams was designed. Based on the Pancharatnam–Berry (P-B) phase principle, the metasurface lens can accurately control the wavefront by adjusting the aspect ratio of the titanium dioxide nanopillars and the rotation angle. When irradiated by left-handed circularly polarized light with a wavelength of 632.8 nm, the optical system can produce multiple micron bottle beams. Taking two bottle beams as examples, the longitudinal full width at half-maximum of the optical tweezers can reach 0.85 and 1.12 microns respectively, and the transverse full width at half-maximum can reach 0.46 and 0.6 microns. And the number of generated bottle beams can be varied by controlling the size of the annular obstacle. By changing the x-component of the unit rotation angle, the metasurface can also change the shape of the bottle beam-the beam cross-section can be changed from circular to elliptical. This paper also analyzes the trapping of ytterbium atoms by the multi bottle beam as optical tweezers. It is found that the multi bottle beam can cool and trap multiple ytterbium atoms.

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Section: Introductionmentioning

confidence: 99%

Multiple bottle beams based on metasurface optical field modulation and their capture of multiple atoms

Xichun

Wensheng

et al. 2022

Chinese Phys. B

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“…The proposed device holds an extra fiber optic, with possibility to use as a light guide for clinical procedures such as treatment with high-power laser ablation, photodynamic therapy (PDT), or even photobiostimulation [22]. Also, this extra fiber could account for the development of an intelligent laser system: by analyzing biological tissue with Raman spectroscopy, the system could define instantly a more adequate treatment (laser type and power) depending on tissue Raman diagnosis [23].…”

mentioning

confidence: 99%

Multifiber optical catheter with bending control of distal end: Applications of Raman biospectroscopy

et al. 2007

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This work demonstrates a multifiber optical catheter with bending control of the distal end, whose main use is to collect Raman signal for biospectroscopy. Also, a method for fiber background subtraction is presented, allowing removal of fiber emission peaks from gross Raman spectrum. The fiber optic catheter with seven fiber optics wrapped up in a resin and a biocompatible flexible teflon tube has been modified to incorporate a mechanical device with gauntlet, which allows bending of the distal extremity to access a desired location obeying the anatomy of the organ. The mechanical device (gauntlet) was built halfway from the catheter proximal excitation tip, allowing the bending of the distal end of about 38 mm diameter. Dispersive Raman spectra at 785 nm excitation wavelength from samples were measured without and with bending (from 120 mm decreasing to 14 mm) of the distal end of the catheter. An optical catheter without the gauntlet was used as a reference. Results demonstrated that both catheters (with bending mechanism and standard one) had about the same Raman signal when the device was bent semicircularly to 38 mm diameter (bending limit for the mechanism), with negligible implication to the Raman signal-to-noise relation (SNR) from sample. When both catheters were bent in a full turn, the Raman signal decreased to about 40% when bending reached 14 mm diameter, mainly due to losses introduced by changes in the fiber total internal reflection. The background removal was efficient, with minimum residual from fiber peaks. This optical catherer could be very useful in laser diagnosis and clinical applications, introducing a way to control the fiber tip position and angle on the tissue or organ.

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Technical developments for cerebral thermal treatment: water-cooled diffusing laser fibre tips and temperature-sensitive MRI using intersecting image planes

McNichols

Kangasniemi

Gowda

et al. 2004

International Journal of Hyperthermia

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The aim was to determine if water-cooled diffusing tips could produce larger and safer (better controlled) thermal lesions than non-cooled diffusing tips at 980 nm. Thermal lesions were induced in beef myocardium in vitro with and without water cooling using a 980 nm diode laser at various power levels. Seven intracerebral treatments were performed in six canines using water-cooled diffusing tips with four animals having intracerebral transmissible venereal tumours grown from inoculate. Magnetic resonance thermal imaging (MRTI)-based feedback software using a fast, radio frequency-spoiled gradient echo acquisition with two intersecting image planes was used for on-line monitoring and control of treatment and for the evaluation of in vivo laser lesion production. In cases where two-plane MRTI was employed, the maximum calculated temperature was compared in each plane. Using water-cooled tips and 400 micro m core diameter laser diffusing fibres in in vitro beef myocardium, power of up to 9.5 W was applied for 8 min without tip failure. Without cooling, tip failure occurred in under 4 min at 6 W, in under 2 min at 7 W and instantaneously at 8 W. Additionally, char accompanied lesions made with uncooled tips while cooled application resulted in only minimal char at only the highest thermal dose. Achieved lesion cross-sectional diameters in in vitro samples were up to 26.5 x 23.3 mm when water cooling was used. In canine brain and transmissible venereal tumours, up to 18.1 x 21.4 mm lesions were achieved. It is concluded that water cooling allows safe application of higher power to small core diameter diffusing tip fibres, which results in larger thermal lesions than can be achieved without cooling. Two-plane MRTI enhances on-line monitoring and feedback of thermal treatment.

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Cooled-Tip Diode Laser Catheter for Improved Catheter Ablation of Ventricular Tachycardia

Cited by 7 publications

References 31 publications

Multiple bottle beams based on metasurface optical field modulation and their capture of multiple atoms

Multiple bottle beams based on metasurface optical field modulation and their capture of multiple atoms

Multifiber optical catheter with bending control of distal end: Applications of Raman biospectroscopy

Technical developments for cerebral thermal treatment: water-cooled diffusing laser fibre tips and temperature-sensitive MRI using intersecting image planes

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