Dr. Jürgen Helfmann Profile

Dr. Jürgen Helfmann

at Laser- und Medizin-Technologie GmbH Berlin

SPIE Involvement:

Author

Publications (30)

SPIE Journal Paper | 20 October 2016 Open Access

Open Access

Comparison of different cutaneous carotenoid sensors and influence of age, skin type, and kinetic changes subsequent to intake of a vegetable extract

Martina Meinke, Sabine Schanzer, Silke Lohan, Ihar Shchatsinin, Maxim Darvin, Henning Vollert, Björn Magnussen, Wolfang Köcher, Jürgen Helfmann, Jürgen Lademann

JBO, Vol. 21, Issue 10, 107002, (October 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.10.107002

KEYWORDS: Skin, Sensors, Blood, Calibration, Reflectance spectroscopy, Raman spectroscopy, Remote sensing, Scanning electron microscopy, Reflectivity, Plasma

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SPIE Journal Paper | 9 April 2014 Open Access

Open Access

Errata: Evaluation of Raman spectroscopic macro raster scans of native cervical cone biopsies using histopathological mapping

Carina Reble, Ingo Gersonde, Cathrin Dressler, Jürgen Helfmann, Wolfgang Kühn, Hans Eichlera

JBO, Vol. 19, Issue 04, 049801, (April 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.4.049801

KEYWORDS: Raman spectroscopy, Spectroscopy, Raster graphics, Biopsy, Biomedical optics, Data analysis, Atomic, molecular, and optical physics

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SPIE Journal Paper | 18 February 2014 Open Access

Open Access

Evaluation of Raman spectroscopic macro raster scans of native cervical cone biopsies using histopathological mapping

Carina Reble, Ingo Gersonde, Cathrin Dressler, Jürgen Helfmann, Wolfgang Kühn, Hans Joachim Eichler

JBO, Vol. 19, Issue 02, 027007, (February 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.2.027007

KEYWORDS: Raman spectroscopy, Tissues, Biopsy, Pathology, Tissue optics, Spectroscopy, Diagnostics, Raster graphics, In vivo imaging, Iodine

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Proceedings Article | 15 June 2011 Paper

Paper

Evaluation of a novel fiber probe for spatially and spectrally resolved reflectance measurements of turbid media

Ingo Gersonde, Stefan Andree, Carina Reble, Jürgen Helfmann, Heiko Luckmann

Proceedings Volume 8087, 80872C (2011) https://doi.org/10.1117/12.889794

KEYWORDS: Absorption, Calibration, Scattering, Integrating spheres, Reflectivity, Reflection, Spectrometers, Tissues, Skin, Silicon

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Proceedings Article | 10 June 2011 Paper

Paper

Determination of chromophore concentrations from spatially resolved skin measurements

Stefan Andree, Jürgen Helfmann, Ingo Gersonde

Proceedings Volume 8087, 808716 (2011) https://doi.org/10.1117/12.889793

KEYWORDS: Absorption, Skin, Blood, Chromophores, Tissue optics, In vivo imaging, Reflectivity, Scattering, Tissues, Monte Carlo methods

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SPIE Journal Paper | 1 November 2010 Open Access

Open Access

Evaluation of a novel noncontact spectrally and spatially resolved reflectance setup with continuously variable source-detector separation using silicone phantoms

Stefan Andree, Carina Reble, Jürgen Helfmann, Ingo Gersonde, Gerd IIIing

JBO, Vol. 15, Issue 06, 067009, (November 2010) https://doi.org/10.1117/12.10.1117/1.3526367

KEYWORDS: Absorption, Scattering, Reflectivity, Sensors, Silicon, Photons, Monte Carlo methods, Optical properties, Signal detection, Titanium dioxide

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SPIE Journal Paper | 1 September 2010 Open Access

Open Access

Influence of osmolarity on the optical properties of human erythrocytes

Moritz Friebel, Jürgen Helfmann, Martina Meinke

JBO, Vol. 15, Issue 05, 055005, (September 2010) https://doi.org/10.1117/12.10.1117/1.3486542

KEYWORDS: Scattering, Mie scattering, Absorption, Blood, Refractive index, Optical properties, Anisotropy, Integrating spheres, Oxygen, Light scattering

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SPIE Journal Paper | 1 May 2010 Open Access

Open Access

Quantitative Raman spectroscopy in turbid media

Carina Reble, Ingo Gersonde, Stefan Andree, Hans-Joachim Eichler, Jürgen Helfmann

JBO, Vol. 15, Issue 03, 037016, (May 2010) https://doi.org/10.1117/12.10.1117/1.3456370

KEYWORDS: Raman spectroscopy, Optical properties, Monte Carlo methods, Raman scattering, Reflectivity, Diffuse reflectance spectroscopy, Optical fibers, Tissues, Scattering, Tissue optics

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SPIE Journal Paper | 1 September 2009 Open Access

Open Access

Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception

Moritz Friebel, Kirsten Povel, Hans-Joachim Cappius, Jürgen Helfmann, Martina Meinke

JBO, Vol. 14, Issue 05, 054029, (September 2009) https://doi.org/10.1117/12.10.1117/1.3250292

KEYWORDS: Monte Carlo methods, Composites, Scattering, Optical properties, Reflectivity, Color vision, Absorption, Teeth, Light scattering, Particles

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Proceedings Article | 8 July 2009 Paper

Paper

Spatially resolved reflectance used to deduce absorption and reduced scattering coefficients

Ingo Gersonde, Stefan Andree, Gerd Illing, Jürgen Helfmann, Carina Reble

Proceedings Volume 7368, 73680I (2009) https://doi.org/10.1117/12.831601

KEYWORDS: Absorption, Scattering, Monte Carlo methods, Reflectivity, Spectroscopy, Tissue optics, Silicon, Diffusion, Laser scattering, Titanium dioxide

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Proceedings Article | 8 July 2009 Paper

Paper

Correction of Raman signals for tissue optical properties

Carina Reble, Stefan Andree, Jürgen Helfmann, Ingo Gersonde, Gerd Illing

Proceedings Volume 7368, 73680C (2009) https://doi.org/10.1117/12.831595

KEYWORDS: Raman spectroscopy, Optical properties, Skin, Raman scattering, Monte Carlo methods, Tissue optics, Absorption, Reflectivity, Scattering, Tissues

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Proceedings Article | 1 July 2009 Paper

Paper

MEMS-based confocal laser scanning microscope for in vivo imaging

Ingo Gersonde, Gerd Illing, Rijk Schütz, Jürgen Helfmann

Proceedings Volume 7367, 73671P (2009) https://doi.org/10.1117/12.831536

KEYWORDS: Microscopes, Confocal microscopy, Luminescence, In vivo imaging, Skin, Reflectivity, Laser scanners, Ronchi rulings, Image quality, Indocyanine green

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SPIE Journal Paper | 1 May 2009 Open Access

Open Access

Influence of oxygen saturation on the optical scattering properties of human red blood cells in the spectral range 250 to 2000 nm

Moritz Friebel, Jürgen Helfmann, Uwe Netz, Martina Meinke

JBO, Vol. 14, Issue 03, 034001, (May 2009) https://doi.org/10.1117/12.10.1117/1.3127200

KEYWORDS: Absorption, Oxygen, Blood, Scattering, Anisotropy, Mie scattering, Monte Carlo methods, Biomedical optics, Optical spheres, Integrating spheres

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SPIE Journal Paper | 1 September 2007 Open Access

Open Access

Influence of shear rate on the optical properties of human blood in the spectral range 250 to 1100 nm

Moritz Friebel, Jürgen Helfmann, Gerhard Müller, Martina Meinke

JBO, Vol. 12, Issue 05, 054005, (September 2007) https://doi.org/10.1117/12.10.1117/1.2799154

KEYWORDS: Blood, Absorption, Scattering, Plasma, Optical properties, Anisotropy, Mie scattering, Integrating spheres, Light scattering, Monte Carlo methods

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Proceedings Article | 13 July 2007 Paper

Paper

Peptide-based optical contrast agents for targeting of intestinal malignancies

Jürgen Helfmann, Andreas Frey, Mario Bürger, Niels Röckendorf, Naho Fujimoto, Katrin Wehry

Proceedings Volume 6633, 66332A (2007) https://doi.org/10.1117/12.728404

KEYWORDS: Luminescence, Capillaries, Tumors, Glasses, Tissue optics, Tissues, Photon counting, Fluorescence spectroscopy, Endoscopy, Target detection

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SPIE Journal Paper | 1 January 2007 Open Access

Open Access

Optical properties of platelets and blood plasma and their influence on the optical behavior of whole blood in the visible to near infrared wavelength range

Martina Meinke, Gerhard Müller, Jürgen Helfmann, Moritz Friebel

JBO, Vol. 12, Issue 01, 014024, (January 2007) https://doi.org/10.1117/12.10.1117/1.2435177

KEYWORDS: Plasma, Blood, Scattering, Absorption, Optical properties, Refractive index, Rayleigh scattering, Anisotropy, Monte Carlo methods, Proteins

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Proceedings Article | 2 April 1998 Paper

Paper

New application system for simultaneous laser and ultrasonic transmission in endoscopic surgery (LUST)

Juergen Helfmann, Thomas Stein, K. Liebold, Gerhard Mueller, Kai Desinger

Proceedings Volume 3249, (1998) https://doi.org/10.1117/12.304356

KEYWORDS: Ultrasonography, Optical fibers, Tissues, Laser therapeutics, Laser tissue interaction, Surgery, Silica, Glasses, Fiber lasers, Laser vision correction

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A new combined Laser and Ultrasound Surgical Therapy (LUST) device for an endoscopically suitable coagulation and tissue fragmentation based on the transmission of laser radiation and ultrasound via flexible silica glass fibers was developed at the LMTB. The ultrasound tissue interaction is based on the well-known CUSA-technology, which enables the surgeon to cut various types of tissue with different degrees of effectiveness. This selective cutting performance is a very useful feature, e.g. for a brain tumor extirpation, where it must be guaranteed that vessels and nerves are not affected while ensuring a fast reduction of the tumor mass. Application fields are in oncology, neurosurgery and angioplasty. The laser radiation can be used for tissue coagulation purposes and homeostasis. With a fiber based LUST-system working at a resonance frequency of 30 kHz, using a laser-vibrometer, velocity amplitudes of up to 20 m/s could be detected at the distal end which corresponds to an elongation of more than 100 micrometers . The investigations have shown that the velocity amplitude, next to suction, frequency and cross section of the active fiber tip, has the greatest impact on the fragmentation rate. With a suction setting of 5 W, the following tissue fragmentation rates could be achieved with a 1.3 mm² fiber cross section and a tip amplitude velocity of 12 m/s: brain tissue 50 mg/s, liver 4,5 mg/s and kidney 4 mg/s. Laser radiation up to 25 watt was sufficient to coagulate soft tissue. This new approach in developing an application system for the therapeutical use of laser radiation and ultrasound via optical waveguides offers new possibilities in minimally invasive surgery, providing a complete new working sphere for the surgeon. The flexible opto-acoustic waveguide (400 - 1700 micrometers ) can be bent making areas accessible which were inaccessible before. The surgeon can use the laser radiation for tissue coagulation or cutting and the ultrasound for tissue fragmentation and tissue reduction without changing the instrumentation.

Proceedings Article | 18 April 1997 Paper

Paper

Longitudinal vibration response of a curved fiber used for laser ultrasound surgical therapy (LUST)

S. Makarov, J. Pankau, Gerhard Mueller, M. Ochmann, Thomas Stein, Juergen Helfmann, Kai Desinger

Proceedings Volume 2977, (1997) https://doi.org/10.1117/12.271018

KEYWORDS: Ultrasonography, Fiber lasers, Laser therapeutics, Silica, Glasses, Tissues, Transducers, Acoustics, Endoscopy, Optical fibers

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Proceedings Article | 11 December 1996 Paper

Paper

Scanning photon density angiography of superficial vessels

Gerhard Mueller, Rijk Schuetz, Juergen Helfmann

Proceedings Volume 2927, (1996) https://doi.org/10.1117/12.260648

KEYWORDS: Luminescence, Tissue optics, Angiography, Phase shifts, Backscatter, Modulation, Skin, Tissues, Heart, Reconstruction algorithms

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Proceedings Article | 3 December 1996 Paper

Paper

New application system for laser and ultrasonic therapy in endoscopic surgery

Juergen Helfmann, Gerhard Mueller, Kai Desinger, Thomas Stein

Proceedings Volume 2922, (1996) https://doi.org/10.1117/12.260694

KEYWORDS: Optical fibers, Laser therapeutics, Ultrasonography, Tissues, Surgery, Ultrasonics, Silica, Glasses, Laser vision correction, Waveguides

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Flexible acoustic waveguides for selective tissue fragmentation are not yet commercially available. Experimental studies have shown the possibility of transmission of acoustical transients via optical silica glass fibers. The aim of this project is the development of a new endoscopic application system that would enable surgeons to use the laser and the ultrasound technique for therapy simultaneously. The concept of this application system is based on the transmission of laser radiation and ultrasound power via flexible silica glass fibers. Theoretical and experimental results on the feasibility of such an application system for an ultrasonic power delivery system are presented. Piezo-electric transducers are used to provide a high efficiency in generating the ultrasonic power. With reference to the CUSA-technique, a special flexible guiding system has been designed for providing aspiration at the tip and for protection of the fiber. The system transmits via an optical fiber up to 100 Watt Nd:YAG laser radiation. The axial oscillation of the fiber tip is +/- micrometers at a frequency of 27 kHz. First results of in vitro experiments are presented. The parenchymatous cells of liver can be fragmented without destruction of the collagenous matrix. The laser can be optionally used to coagulate bleedings or to cut collagenous tissues in contact. Applications for an acoustical and optical waveguide in ultrasonic surgery are demonstrated. This new approach in developing a first application system for the therapeutical use of laser radiation and power ultrasound in minimal invasive surgery via optical waveguides offers new possibilities in surgery. The laser ultrasonic surgical therapy (LUST) with its thin and flexible applicator provides new working fields especially for neuro or liver surgery. The tip can be bent and thus areas which could not be treated before have now been made accessible. Without changing the instrumentation, the surgeon can use the laser for tissue coagulation or cutting, next to the selective ultrasonic tissue fragmentation, where nerves or vessels will not be affected. Such a LUST-application system could be ready for clinical use in two to four years.

Proceedings Article | 10 June 1996 Paper

Paper

Phase demodulation imaging of coagulation-necrosis in biological tissue

Gerhard Mueller, Andre Roggan, Rijk Schuetz, Juergen Helfmann, Rolf-Dieter Naber, Viravuth Prapavat, Juergen Beuthan

Proceedings Volume 2802, (1996) https://doi.org/10.1117/12.242158

KEYWORDS: Laser scattering, Tissue optics, Scattering, Signal attenuation, Light scattering, In vitro testing, Tissues, Demodulation, Phase velocity, Modulation

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Proceedings Article | 18 December 1995 Paper

Paper

Imaging of xenofluorescent objects in strongly scattering media: first results

J. Fikau, N. Bodammer, Gerhard Mueller, Rijk Schuetz, Rainier Senz, Juergen Helfmann

Proceedings Volume 2626, (1995) https://doi.org/10.1117/12.228672

KEYWORDS: Luminescence, Modulation, Tissue optics, Near infrared, Fluorescence spectroscopy, Scattering media, Angiography, Signal attenuation, Absorption, Phase shift keying

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Proceedings Article | 28 July 1994 Paper

Paper

Transmission of laser radiation and acoustical waves via optical fibers for surgical therapy

A. Aspidov, Matthias Herrig, Vladimir Zharov, Juergen Helfmann, Johannes Tschepe, G. Savrasov, Kai Desinger, Gerhard Mueller

Proceedings Volume 2131, (1994) https://doi.org/10.1117/12.180760

KEYWORDS: Optical fibers, Ultrasonography, Glasses, Laser therapeutics, Silica, Fiber lasers, Transducers, Tissues, Plasma, Metals

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Proceedings Article | 28 July 1994 Paper

Paper

IR fiber radiometry for high-temperature measurements during laser-tissue-interaction

Wolfgang Waesche, Abraham Katzir, Edward Belotserkovsky, Matthias Herrig, Gerhard Mueller, Johannes Tschepe, Andre Roggan, Juergen Helfmann

Proceedings Volume 2131, (1994) https://doi.org/10.1117/12.180759

KEYWORDS: Temperature metrology, Radiometry, Nd:YAG lasers, Tissues, Calibration, Laser tissue interaction, Sensors, Natural surfaces, Fiber lasers, Liver

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Proceedings Article | 15 February 1994 Paper

Paper

New alternative for laser lithotropsy-long pulse passively q-switched solid-state laser with fiber-based resonator

E. Shklovsky, Gerhard Mueller, Vitali Konov, V. Tumorin, Pavel Pashinin, Vladimir Pashinin, Juergen Helfmann

Proceedings Volume 2086, (1994) https://doi.org/10.1117/12.169122

KEYWORDS: Plasma, Pulsed laser operation, Fiber lasers, Laser applications, Acoustics, Nd:YAG lasers, Cavitation, Laser damage threshold, Solid state lasers, Resonators

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Proceedings Article | 1 February 1994 Paper

Paper

Acoustical waves via optical fibers for biomedical applications

A. Aspidov, Johannes Tschepe, Gerhard Mueller, Juergen Helfmann, Vladimir Zharov, Matthias Herrig, G. Savrasov

Proceedings Volume 2084, (1994) https://doi.org/10.1117/12.167326

KEYWORDS: Optical fibers, Ultrasonography, Silica, Glasses, Tissues, Laser therapeutics, Laser cutting, Biomedical optics, Coating, Endoscopes

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Proceedings Article | 28 May 1993 Paper

Paper

Tissue differentiation using laser-induced shock waves by detection of acoustic transients through an optical wave-guide

Johannes Tschepe, Thomas Ahrens, Gerhard Mueller, Juergen Helfmann, Valentin Gapontsev

Proceedings Volume 1893, (1993) https://doi.org/10.1117/12.146351

KEYWORDS: Plasma, Optical fibers, Acoustics, Signal detection, Glasses, Laser tissue interaction, Fiber lasers, Silica, Sensors, Medicine

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Proceedings Article | 1 August 1992 Paper

Paper

Feasability of fiber optic delivery in medicine (Invited Paper)

Johannes Tschepe, Bernhard Hug, Gerhard Mueller, Juergen Helfmann, Frank Zgoda, Brita Schaldach, Klaus Doerschel, Hans-Peter Berlien

Proceedings Volume 1649, (1992) https://doi.org/10.1117/12.60233

KEYWORDS: Medicine, Laser damage threshold, Optical fibers, Laser therapeutics, Fiber lasers, Safety, Pulsed laser operation, Laser tissue interaction, Fiber optics, Tissues

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Proceedings Article | 1 June 1992 Paper

Paper

Efficiency of stone fragmentation by long pulses of a Q-switched Nd:YAG laser

B. Mikhailov, Alexander Silenok, S. Pak, Ivan Shcherbakov, Vitali Konov, D. Nikolaev, Juergen Helfmann, Gerhard Mueller

Proceedings Volume 1643, (1992) https://doi.org/10.1117/12.137328

KEYWORDS: Pulsed laser operation, Plasma, Optical fibers, Laser therapeutics, Nd:YAG lasers, Q switched lasers, Liquids, Oscillators, Energy efficiency, Laser vision correction

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Proceedings Article | 1 July 1990 Paper

Paper

Laser lithotripsy using double pulse technique

Juergen Helfmann, Gerhard Mueller, Klaus Doerschel

Proceedings Volume 1201, (1990) https://doi.org/10.1117/12.17547

KEYWORDS: Absorption, Pulsed laser operation, Calculi, Fiber lasers, Medicine, Plasma, Optical fibers, Laser damage threshold, Laser lithotripsy, Nd:YAG lasers

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Showing 5 of 30 publications

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