1. Articles from peter e. andersen

    1-22 of 22
    1. Optical Radiomic Signatures Derived from Optical Coherence Tomography Images to Improve Identification of Melanoma

      Optical Radiomic Signatures Derived from Optical Coherence Tomography Images to Improve Identification of Melanoma

      The current gold standard for the clinical diagnosis of melanoma is excisional biopsy and histopathologic analysis. Approximately 15-30 benign lesions are biopsied to diagnose each melanoma. Additionally, biopsies are invasive and result in pain, anxiety, scarring and disfigurement of patients which can add an additional burden to the health care system. Among several imaging techniques developed to enhance melanoma diagnosis, optical coherence tomography (OCT), with its high-resolution and intermediate penetration depth, can potentially provide required diagnostic information noninvasively. Here we present an image analysis algorithm, 'optical properties extraction (OPE)', that improves the specificity and sensitivity of OCT by identifying unique ...

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    2. Semiconductor Lasers and Diode-based Light Sources for Biophotonics (Textbook)

      Semiconductor Lasers and Diode-based Light Sources for Biophotonics (Textbook)

      Semiconductor lasers are small, reliable, low cost, high-performance and user-friendly optical devices which make them highly suitable for a variety of biomedical applications. This edited book gathers experts in the field to cover the fundamentals and technology advances of semiconductor lasers and diode-based lasers with a focus on their applications in medical optics and biophotonics including edge-emitting semiconductor lasers and light emitting diodes, Q-switched and mode-locked lasers, quantum cascade lasers, semiconductor disk lasers, near-infrared spectroscopy systems for biomedical applications, bio-medical Raman spectroscopy, nonlinear imaging and optical coherence tomography.

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    3. Special section guest editorial: selected topics in biophotonics: optical coherence tomography and biomolecular imaging with coherent Raman scattering microscopy

      Special section guest editorial: selected topics in biophotonics: optical coherence tomography and biomolecular imaging with coherent Raman scattering microscopy

      The Special Section on Selected Topics in Biophotonics: Optical Coherence Tomography and Biomolecular Imaging with Coherent Raman Scattering Microscopy comprises two invited review papers and several contributed papers from the summer school Biophotonics ’13, as well as contributed papers within this general scope.

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    4. Compact green-diode-based lasers for biophotonic bioimaging

      Compact green-diode-based lasers for biophotonic bioimaging

      Lasers based on semiconductor materials, so-called diode lasers, are highly efficient, compact light sources. 1 In high volume they can also be produced at very low cost. In contrast to lasers based on specific atomic transitions, such as solid-state or gas lasers, diode laser materials engineering enables generation of light in a large portion of the optical spectrum. 2 The great versatility of diode lasers allows their direct use in many biophotonics applications, including photocoagulation, 3 diffuse optical imaging, 4 and optical coherence tomography (OCT). 5, 6 Nonlinear frequency conversion of diode lasers is an attractive method of overcoming the ...

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    5. Skin Cancer A Practical Approach (Textbook)

      Skin Cancer A Practical Approach (Textbook)

      Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described as the optical analogue to ultrasound. The inherent safety of the technology allows for in vivo use of OCT in patients. The main strength of OCT is the depth resolution. In dermatology, most OCT research has turned on non-melanoma skin cancer (NMSC) and non-invasive monitoring of morphological changes in a number of skin diseases based on pattern recognition ...

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    6. OCT Pioneer Professor Wolfgang Drexler to Teach Short Course on OCT at Biophotonics ’13 at Island of Ven, Sweden

      OCT Pioneer Professor Wolfgang Drexler to Teach Short Course on OCT at Biophotonics ’13 at Island of Ven, Sweden

      The 6 th International Graduate Summer School Biophotonics '13 will take place 8-15 June 2013 at Backafallsbyn on the Island of Ven, Sweden. The registration to apply to attend Biophotonics '13 is now open. Please take a moment to read the instructions below carefully before starting to fill out the online application form. Application form In order to apply by filling out the online form, you need to provide the following: information about yourself (the applicant), information about your main supervisor, title and abstract of your research to be presented at the school. Fee The registration fee for participation, including ...

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    7. Feature Of The Week 1/13/13: Technical University of Denmark Publishes Detailed Quantitative Analysis of 1060nm Window for Optimal OCT Retinal Imaging

      Feature Of The Week 1/13/13: Technical University of Denmark Publishes Detailed Quantitative Analysis of 1060nm Window for Optimal OCT Retinal Imaging

      During the past decade, the wavelength range around the local water absorption minimum at 1060 nm has found increasing interest in the OCT community, as it allows imaging of the human posterior eye segment with improved penetration depth into the choroid and the sclera. However, the neighboring water absorption bands narrow the bandwidth of probing light, and reduce thus the achievable axial resolution. A detailed quantitative analysis of this effect has been missing until now, but has become increasingly relevant due to the availability of new light sources (SLDs, swept sources) with bandwidths in excess of 100 nm. For light ...

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    8. Investigation of the impact of water absorption on retinal OCT imaging in the 1060 nm range

      Investigation of the impact of water absorption on retinal OCT imaging in the 1060 nm range

      Recently, the wavelength range around 1060 nm has become attractive for retinal imaging with optical coherence tomography (OCT), promising deep penetration into the retina and the choroid. The adjacent water absorption bands limit the useful bandwidth of broadband light sources, but until now, the actual limitation has not been quantified in detail. We have numerically investigated the impact of water absorption on the axial resolution and signal amplitude for a wide range of light source bandwidths and center wavelengths. Furthermore, we have calculated the sensitivity penalty for maintaining the optimal resolution by spectral shaping. As our results show, with currently ...

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    9. Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

      Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

      Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera) due to low absorption in water and deep penetration into the tissue. Rapidly tunable light sources, such as Fourier domain mode-locked (FDML) lasers, enable acquisition of densely sampled three-dimensional datasets covering a wide field of view. However, semiconductor optical amplifiers (SOAs)-the typical laser gain media for swept sources-for the 1060nm band could until recently only provide relatively low output power and bandwidth. We have implemented an FDML laser using a new SOA featuring broad gain bandwidth ...

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    10. Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

      Direct pumping of ultrashort Ti:sapphire lasers by a frequency doubled diode laser

      A simple and robust diode laser system emitting 1.28 W of green light suitable for pumping an ultrafast Ti:sapphire laser is presented. To classify our results, the diode laser is compared to a standard, commercially available diode pumped solid-state (DPSS) laser system pumping the same oscillator. When using our diode laser system, the optical conversion efficiencies from green to near-infrared light reduces to 75 % of the values achieved with the commercial pump laser. Despite this reduction the overall efficiency of the Ti:sapphire laser is still increased by a factor > 2 due to the superior electro-optical efficiency of ...

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    11. How histological features of basal cell carcinomas influence image quality in optical coherence tomography

      How histological features of basal cell carcinomas influence image quality in optical coherence tomography
      Optical coherence tomography (OCT) has the potential to diagnose and measure the depth of nonmelanoma skin cancer (NMSC) in skin, but some lesions appear blurred in OCT images. The aim of this study is to identify histological characteristics of basal cell carcinomas (BCC) that correlate with good quality OCT images of the same lesions. A total of 34 patients with BCC were OCT scanned. The influence of histology parameters (e.g. inflammation, sun damage of skin, carcinoma cell size) on OCT image quality was studied by comparing 15 BCC lesions easily identified compared to 19 BCC lesions that produced only ...
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    12. Optical coherence tomography-current technology and applications in clinical and biomedical research

      Optical coherence tomography-current technology and applications in clinical and biomedical research
      Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real-time two- and three-dimensional images of scattering samples with micrometer resolution. By mapping the local reflectivity, OCT visualizes the morphology of the sample. In addition, functional properties such as birefringence, motion, or the distributions of certain substances can be detected with high spatial resolution. Its main field of application is biomedical imaging and diagnostics. In ophthalmology, OCT is accepted as a clinical standard for diagnosing and monitoring the treatment of a number of retinal diseases, and OCT is becoming an important instrument for clinical cardiology. New applications are emerging ...
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    13. Fourier domain mode-locked swept source
 at 1050 nm based on a tapered amplifier

      Fourier domain mode-locked swept source
 at 1050 nm based on a tapered amplifier

      While swept source optical coherence tomography (OCT) in the 1050 nm range is promising for retinal imaging, there are certain challenges. Conventional semiconductor gain media have limited output power, and the performance of high-speed Fourier domain mode-locked (FDML) lasers suffers from chromatic dispersion in standard optical fiber. We developed a novel light source with a tapered amplifier as gain medium, and investigated the FDML performance comparing two fiber delay lines with different dispersion properties. We introduced an additional gain element into the resonator, and thereby achieved stable FDML operation, exploiting the full bandwidth of the tapered amplifier despite high dispersion ...

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    14. FDML swept source at 1060 nm using a tapered amplifier

      FDML swept source at 1060 nm using a tapered amplifier

      We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources in this wavelength range. We demonstrate that a tapered amplifier can be integrated into a fiber-based swept source and allows for high-speed FDML operation. The developed light source operates at a sweep rate of 116kHz with an effective average output power in excess of 30mW. With a total sweep range of 70 nm an axial resolution of 15 µm ...

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    15. OCT imaging of skin cancer and other dermatological diseases

      Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a large number of applications in the fields of non-melanoma skin cancer, malignant melanomas, psoriasis and dermatitis, infestations, bullous skin diseases, tattoos, nails, haemangiomas, and other skin diseases
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    16. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

      We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance of ... [Proc. SPIE 7168, 716824 (2009)] published Fri Feb 20, 2009.

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    17. Optical Coherence Tomography: Technique and Applications (Book Chapter)

      Optical Coherence Tomography: Technique and Applications (Book Chapter)
      Optical coherence tomography (OCT) is a noninvasive optical imaging modality providing real-time video rate images in two and three dimensions of biological tissues with micrometer resolution. OCT fills the gap between ultrasound and confocal microscopy, since it has a higher resolution than ultrasound and a higher penetration than confocal microcopy. Functional extensions are also possible, i.e., flow, birefringence or spectroscopic measurements with high spatial resolution. In ophthalmology, OCT is accepted as a clinical standard for diagnosing and monitoring the treatment of a number of retinal diseases. The potential of OCT in many other applications is currently being explored, such ...
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    18. Optical amplification in coherent optical frequency modulated continuous wave reflectometry

      The present invention relates to an apparatus for optical coherence reflectometry, in particular for optical coherence tomography, wherein the apparatus for optical coherence reflectometry comprises a wavelength scanning laser source for providing a light signal, and splitting means for dividing said light signal into a sample light field and a reference light field, wherein the sample light field is directed to the sample being measured, and the light reflected from the sample is amplified without correspondingly amplifying the light reflected in the reference light field. Thereby, it is possible to direct substantially all light energy from the first reflected light ...
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    19. A Continuously Swept Frequency Laser Source (Wo 2005/022709)

      A Continuously Swept Frequency Laser Source (Wo 2005/022709)
      The present invention relates to a method for producing a substantially continuously swept frequency laser output, a substantially continuously frequency scanning laser source, a method and a system for providing a result image of a sample using the substantially continuously frequency scanning laser source. The system includes a seed pulse generator for generating a chirped seed pulse that enters an optical ring circuit comprising a frequency shifting device. For each round the light pulse travels in the ring, the frequency is shifted. The substantially continuously frequency scanning laser source is useful for any application normally incorporating a frequency scanning laser ...
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    20. Optical amplification in coherence reflectometry

      The present invention relates to an apparatus and a method for optical coherence reflectometry, in particular for optical coherence tomography. The invention particularly relates to the route of the light field in the sample arm. The reflected light field in the sample arm is amplified before being received by a combining means, said combining means being capable of receiving the reflected light field from the sample arm as well as the second reflected light field from the reference arm. Thereby, it is possible to direct substantially all light energy in the sample arm to the combining means, and to obtain ...
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    1-22 of 22
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  2. Topics in the News

    1. (22 articles) Peter E. Andersen
    2. (20 articles) Technical University of Denmark (DTU)
    3. (9 articles) Sebastian Marschall
    4. (6 articles) Christian R. Petersen
    5. (5 articles) Mette Mogensen
    6. (4 articles) University of Copenhagen
    7. (4 articles) Thomas M. Jørgensen
    8. (4 articles) Lars Thrane
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    Optical Coherence Tomography: Technique and Applications (Book Chapter) Quantitative assessment of retinal disorders using polarization-sensitive optical coherence tomography FDML swept source at 1060 nm using a tapered amplifier Fourier domain mode-locked swept source
 at 1050 nm based on a tapered amplifier Optical coherence tomography-current technology and applications in clinical and biomedical research How histological features of basal cell carcinomas influence image quality in optical coherence tomography Investigation of the impact of water absorption on retinal OCT imaging in the 1060 nm range Image contrast correction method in full-field optical coherence tomography Evaluation of posterior vitreous detachment using ultrasonography and optical coherence tomography Optical coherence tomography angiography characteristics of acute retinal arterial occlusion Computed Tomography–Mediated Registration of Trapeziometacarpal Articular Cartilage Using Intraarticular Optical Coherence Tomography and Cryomicrotome Imaging: A Cadaver Study Successful Treatment of Genital Warts with Ingenol Mebutate Monitored with Optical Coherence Tomography and Reflectance Confocal Microscopy