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J. Stuart Nelson - One of the best experts on this subject based on the ideXlab platform.

  • In vivo port-wine stain Depth Determination with a photoacoustic probe
    Applied optics, 2003
    Co-Authors: John A. Viator, Bernard Choi, Martin Ambrose, Jerome Spanier, J. Stuart Nelson
    Abstract:

    We have designed a photoacoustic probe for port-wine stain (PWS) Depth measurements consisting of optical fibers for laser light delivery and a piezoelectric element for acoustic detection. We characterized the capabilities and limitations of the probe for profiling PWS skin. The probe induced and measured photoacoustic waves in acrylamide tissue phantoms and PWS skin in vivo. The optical properties of the phantoms were chosen to mimic those of PWS skin. We denoised acoustic waves using spline wavelet transforms, then deconvolved with the impulse response of the probe to yield initial subsurface pressure distributions in phantoms and PWS skin. Using the phantoms, we determined that the limit in resolving epidermal and PWS layers was less than 70 μm. In addition, we used the phantoms to determine that the maximum epidermal melanin concentration that allowed detection of PWS was between 13 and 20%. In vivo measurements of PWS skin with different epidermal melanin concentrations correlated with the phantoms. Thus the photoacoustic probe can be used to determine PWS Depth for most patients receiving laser therapy.

  • Clinical testing of a photoacoustic probe for port wine stain Depth Determination
    Lasers in surgery and medicine, 2002
    Co-Authors: John A. Viator, Guenther Paltauf, Steven L. Jacques, Scott A. Prahl, Hongwu Ren, Zhongping Chen, J. Stuart Nelson
    Abstract:

    Author(s): Viator, John A; Au, Gigi; Paltauf, Guenther; Jacques, Steven L; Prahl, Scott A; Ren, Hongwu; Chen, Zhongping; Nelson, J Stuart | Abstract: BACKGROUND AND OBJECTIVE:Successful laser treatment of port wine stain (PWS) birthmarks requires knowledge of lesion geometry. Laser parameters, such as pulse duration, wavelength, and radiant exposure, and other treatment parameters, such as cryogen spurt duration, need to be optimized according to epidermal melanin content and lesion Depth. We designed, constructed, and clinically tested a photoacoustic probe for PWS Depth Determination. STUDY DESIGN/MATERIALS AND METHODS:Energy from a frequency-doubled, Nd:YAG laser (lambda=532 nm, tau(p)=4 nanoseconds) was coupled into two 1,500 mum optical fibers fitted into an acrylic handpiece containing a piezoelectric acoustic detector. Laser light induced photoacoustic waves in tissue phantoms and a patient's PWS. The photoacoustic propagation time was used to calculate the Depth of the embedded absorbers and PWS lesion. RESULTS:Calculated chromophore Depths in tissue phantoms were within 10% of the actual Depths of the phantoms. PWS Depths were calculated as the sum of the epidermal thickness, determined by optical coherence tomography (OCT), and the epidermal-to-PWS thickness, determined photoacoustically. PWS Depths were all in the range of 310-570 microm. The experimentally determined PWS Depths were within 20% of those measured by optical Doppler tomography (ODT). CONCLUSIONS:PWS lesion Depth can be determined by a photoacoustic method that utilizes acoustic propagation time.

  • Burn Depth Determination by High-Speed Fiber-Based Polarization Sensitive Optical Coherence Tomography at 1.3 micrometers
    Biomedical Topical Meeting, 2002
    Co-Authors: B H Park, J. Stuart Nelson, Ce Saxer, Shyam M. Srinivas, Johannes F De Boer
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.

  • Burn Depth Determination by high-speed fiber-based polarization-sensitive optical coherence tomography at 1.3 μm
    Coherence Domain Optical Methods in Biomedical Science and Clinical Applications IV, 2000
    Co-Authors: B H Park, Johannes F De Boer, Zhongping Chen, Ce Saxer, Shyam M. Srinivas, Huai-en L. Huang, Binh Q. Ngo, J. Stuart Nelson
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.

Johannes F De Boer - One of the best experts on this subject based on the ideXlab platform.

  • burn Depth Determination in human skin using polarization sensitive optical coherence tomography
    Biomedical optics, 2003
    Co-Authors: Mark C Pierce, Robert L Sheridan, B H Park, Barry Cense, Johannes F De Boer
    Abstract:

    Accurate evaluation of the Depth of injury in burn victims is of considerable practical value to the surgeon, both for initial Determination of resuscitation fluid requirements, and in deciding whether excision and closure of the wound is necessary. Currently, burn Depth is most accurately evaluated by visual inspection, though decisions concerning treatment may not be possible for a number of days post-injury. As part of our ongoing efforts to provide an objective, quantitative method for burn Depth Determination, we present here the results of a study using polarization-sensitive optical coherence tomography (PS-OCT) to detect and measure thermally induced changes in collagen birefringence in skin excised from burn patients. We find that PS-OCT is capable of imaging and quantifying significantly reduced birefringence in burned human skin.

  • Burn Depth Determination by High-Speed Fiber-Based Polarization Sensitive Optical Coherence Tomography at 1.3 micrometers
    Biomedical Topical Meeting, 2002
    Co-Authors: B H Park, J. Stuart Nelson, Ce Saxer, Shyam M. Srinivas, Johannes F De Boer
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.

  • Burn Depth Determination by high-speed fiber-based polarization-sensitive optical coherence tomography at 1.3 μm
    Coherence Domain Optical Methods in Biomedical Science and Clinical Applications IV, 2000
    Co-Authors: B H Park, Johannes F De Boer, Zhongping Chen, Ce Saxer, Shyam M. Srinivas, Huai-en L. Huang, Binh Q. Ngo, J. Stuart Nelson
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.

Kirk W. Madison - One of the best experts on this subject based on the ideXlab platform.

  • Trap-Depth Determination from residual gas collisions
    Physical Review A, 2011
    Co-Authors: J. Van Dongen, Chenchong Zhu, D. Clement, G. Dufour, James Booth, Kirk W. Madison
    Abstract:

    We present a method for determining the Depth of an atomic or molecular trap of any type. This method relies on a measurement of the trap loss rate induced by collisions with background gas particles. Given a fixed gas composition, the loss rate uniquely determines the trap Depth. Because of the ``soft'' long-range nature of the van der Waals interaction, these collisions transfer kinetic energy to trapped particles across a broad range of energy scales, from room temperature to the microkelvin energy scale. The resulting loss rate therefore exhibits a significant variation over an enormous range of trap Depths, making this technique a powerful diagnostic with a large dynamic range. We present trap Depth measurements of a Rb magneto-optical trap using this method and a different technique that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state. The main advantage of the method presented here is its large dynamic range and applicability to traps of any type requiring only knowledge of the background gas density and the interaction potential between the trapped and background gas particles.

  • Trap Depth Determination from background gas collision induced loss rates
    Bulletin of the American Physical Society, 2010
    Co-Authors: Janelle Van Dongen, James L. Booth, Kirk W. Madison
    Abstract:

    1. D. E. Fagnan, J. Wang, C. Zhu., P. Djuricanin, B.G. Klappauf, J. L Booth, K. W. Madison Phys. Rev. A., 80, 022712 (2009) 2. D. Hoffmann, S. Bali, T. Walker, Phys. Rev. A. 54, R1030 (1996) 3. S. Bali, D. Hoffmann, T. Walker, Europhys. Lett, 27 (4), pp.273-277 (1994) • We have demonstrated a technique for determining the trap Depth for any type of trap using loss rates arising from collisions with background gas particles.

Mark C Pierce - One of the best experts on this subject based on the ideXlab platform.

  • burn Depth Determination in human skin using polarization sensitive optical coherence tomography
    Biomedical optics, 2003
    Co-Authors: Mark C Pierce, Robert L Sheridan, B H Park, Barry Cense, Johannes F De Boer
    Abstract:

    Accurate evaluation of the Depth of injury in burn victims is of considerable practical value to the surgeon, both for initial Determination of resuscitation fluid requirements, and in deciding whether excision and closure of the wound is necessary. Currently, burn Depth is most accurately evaluated by visual inspection, though decisions concerning treatment may not be possible for a number of days post-injury. As part of our ongoing efforts to provide an objective, quantitative method for burn Depth Determination, we present here the results of a study using polarization-sensitive optical coherence tomography (PS-OCT) to detect and measure thermally induced changes in collagen birefringence in skin excised from burn patients. We find that PS-OCT is capable of imaging and quantifying significantly reduced birefringence in burned human skin.

B H Park - One of the best experts on this subject based on the ideXlab platform.

  • burn Depth Determination in human skin using polarization sensitive optical coherence tomography
    Biomedical optics, 2003
    Co-Authors: Mark C Pierce, Robert L Sheridan, B H Park, Barry Cense, Johannes F De Boer
    Abstract:

    Accurate evaluation of the Depth of injury in burn victims is of considerable practical value to the surgeon, both for initial Determination of resuscitation fluid requirements, and in deciding whether excision and closure of the wound is necessary. Currently, burn Depth is most accurately evaluated by visual inspection, though decisions concerning treatment may not be possible for a number of days post-injury. As part of our ongoing efforts to provide an objective, quantitative method for burn Depth Determination, we present here the results of a study using polarization-sensitive optical coherence tomography (PS-OCT) to detect and measure thermally induced changes in collagen birefringence in skin excised from burn patients. We find that PS-OCT is capable of imaging and quantifying significantly reduced birefringence in burned human skin.

  • Burn Depth Determination by High-Speed Fiber-Based Polarization Sensitive Optical Coherence Tomography at 1.3 micrometers
    Biomedical Topical Meeting, 2002
    Co-Authors: B H Park, J. Stuart Nelson, Ce Saxer, Shyam M. Srinivas, Johannes F De Boer
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.

  • Burn Depth Determination by high-speed fiber-based polarization-sensitive optical coherence tomography at 1.3 μm
    Coherence Domain Optical Methods in Biomedical Science and Clinical Applications IV, 2000
    Co-Authors: B H Park, Johannes F De Boer, Zhongping Chen, Ce Saxer, Shyam M. Srinivas, Huai-en L. Huang, Binh Q. Ngo, J. Stuart Nelson
    Abstract:

    Burn Depth Determination is a critical factor in the treatment of thermal injury. We have developed a technique, polarization sensitive optical coherence tomography (PS-OCT), to assess burn Depth non-invasively. Thermal injury denatures collagen in human skin. PS-OCT is able to measure the resulting reduction in collagen birefringence using Depth resolved changes in the polarization of light propagated and reflected from the sample. In a previous study, we used a free space PS-OCT system at 850 nm to image in vivo the skin of rats burned for various amounts of time. Using a high-speed system at 1.3 micrometers has the advantages of greater Depth penetration and reduction of motion artifacts due to breathing and small movements of the animal. Stokes vectors were calculated for each point in the scans and the relative birefringence was determined using different incident polarization states. Birefringence was correlated with actual burn Depth determined by histological analysis. Our results show a marked difference between normal tissue and even the slightest burn, and a consistent trend for various degrees of burns.