Non-contact photoacoustic spectroscopy for photoablation control
First Claim
1. A guided non-contact tissue ablation method controllably mediated by recognition of distinct tissue composition within a tissue volume, the method comprising:
- a) impinging multiple pulses of electromagnetic energy onto the tissue to ablate impinged tissue and generate an acoustic pressure wave in response to the electromagnetic energy interacting with the impinged tissue;
b) non-contactingly sensing the generated acoustic pressure wave to provide a plurality of corresponding signals;
c) processing the plurality of signals by applying thereto a cluster analysis algorithm to recognize distinct tissue composition.
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Abstract
A method and system for non-contact laser photoablation to be utilized during vision corrective surgery. Multiple pulses of electromagnetic energy are impinged onto target tissue to ablate and generate an acoustic pressure wave while concurrently processing signals produced by the acoustic pressure wave. A representative pattern can be provided to guide the surgeon through distinct tissue layers encountered in cornea resculpting surgery. Cluster analysis may be utilized to process the acoustic wave signals to generate the representative pattern. Specifically, the representative cluster pattern provides the surgeon with a tool to discern, with increased precision, the tissue layer being ablated and reduces the likelihood of invading a deeper layer of tissue that should not be removed.
71 Citations
34 Claims
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1. A guided non-contact tissue ablation method controllably mediated by recognition of distinct tissue composition within a tissue volume, the method comprising:
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a) impinging multiple pulses of electromagnetic energy onto the tissue to ablate impinged tissue and generate an acoustic pressure wave in response to the electromagnetic energy interacting with the impinged tissue;
b) non-contactingly sensing the generated acoustic pressure wave to provide a plurality of corresponding signals;
c) processing the plurality of signals by applying thereto a cluster analysis algorithm to recognize distinct tissue composition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A non-contact tissue ablation method controllably mediated by recognition of tissue composition, the method comprising:
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a) impinging multiple pulses of electromagnetic energy onto at least one location of the tissue to ablate impinged tissue and to generate at least one acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) non-contactingly sensing the at least one generated acoustic pressure wave to provide a plurality of corresponding photoacoustic signals; and
c) processing the plurality of photoacoustic signals by analyzing frequencies that are characteristic to specific types of tissue to determine change in the ablated tissue. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A guided non-contact tissue ablation method controllably mediated by recognition of tissue composition, the method comprising:
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a) impinging multiple pulses of electromagnetic energy into at least one location of the tissue to ablate impinged tissue and to generate at least one acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) non-contactingly sensing the at least one generated acoustic pressure wave to provide a plurality of photoacoustic signals; and
c) processing the plurality of photoacoustic signals by Fourier transformation, to choose a maximum as a center frequency and at least four closest frequency maxima;
d) analyzing the central frequency and the four closest frequency maxima to determine change in the ablated tissue, using a cluster analysis algorithm.
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24. A guided non-contact tissue ablation method controllably mediated by recognition of tissue composition, the method comprising:
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a) impinging multiple pulses of electromagnetic energy onto at least one location of the tissue to ablate impinged tissue and to generate at least one acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) non-contactingly sensing the at least one generated acoustic pressure wave to provide a plurality of corresponding signals; and
c) processing the plurality of signals by performing cluster analysis using a k-means algorithm to determine change in the ablated tissue.
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25. A guided non-contact tissue ablation method controllably mediated by recognition of tissue composition, the method comprising:
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a) impinging at least two pulses of electromagnetic energy from at least two electromagnetic energy sources onto at least two locations on the tissue to ablate impinged tissue and to generate multiple acoustic waves that superimposed to provide an interference response;
b) non-contactingly sensing the multiple generated acoustic pressure waves and the interference response to provide a plurality of corresponding signals; and
c) processing the plurality of signals by analyzing at least one signal property to determine change in the ablated tissue. - View Dependent Claims (26)
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27. The A guided non-contact tissue ablation method controllably mediated by recognition of tissue composition, the method comprising:
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a) impinging multiple pulses of electromagnetic energy onto at least one location of the tissue to ablate impinged tissue and to generate at least one acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) non-contactingly sensing the at least one generated acoustic pressure wave to provide a plurality of corresponding signals. c) processing the plurality of signals by analyzing at least one signal property to determine change in the ablated tissue; and
d) adjusting impinging electromagnetic energy according to fluid content of tissue.
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28. A guided non-contact tissue ablation system that is controllably mediated by recognition of distinct types of tissue composition, the system comprising:
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a) at least one electromagnetic energy emitting source to generate multiple pulses of electromagnetic energy to ablate impinged tissue and generate an acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) at least one non-contacting sensing means for sensing the acoustic pressure wave and providing a plurality of corresponding photoacoustic signals; and
c) at least one processing means for analyzing the photoacoustic signals of the acoustic pressure wave to determine frequencies that are characteristic to specific types of tissue and to recognize distinct tissue composition based on said characteristic frequencies. - View Dependent Claims (29, 30, 31, 32)
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33. A guided non-contact tissue ablation system that is controllably mediated by recognition of distinct types of tissue composition, the system comprising:
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a) at least one electromagnetic energy emitting source to generate multiple pulses of electromagnetic energy to ablate impinged tissue and generate an acoustic pressure wave in response to the electromagnetic energy impinging the tissue;
b) at least one non-contacting sensing means for sensing the generated acoustic pressure wave and providing a plurality of corresponding signals; and
c) at least one processing means for analyzing the signals of the acoustic pressure wave using a cluster analysis algorithm to recognize distinct tissue composition. - View Dependent Claims (34)
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Specification