Publikationen

2017

  • Baade, A; von der Burchard, C; Lawin, M; Koinzer, S; Schmarbeck, B; Schlott, K; Miura, Y; Roider, J; Birngruber, R and Brinkmann, R: Power-controlled temperature guided retinal laser therapy. J Biomed Opt 22(11), pp. 1-11, 2017
    BibTeX Link
    @article{Baade2017,
       author = {Baade, A; von der Burchard, C; Lawin, M; Koinzer, S; Schmarbeck, B; Schlott, K; Miura, Y; Roider, J; Birngruber, R and Brinkmann, R},
       title = {Power-controlled temperature guided retinal laser therapy},
       journal = {J Biomed Opt} {22(11)},
       
       pages = {1-11},
       ISSN = {1083-3668},
       DOI = {10.1117/1.jbo.22.11.118001},
       year = {2017},
       type = {Journal Article}
    }
    

2016

  • Schlott, Kerstin and Koinzer, Stefan and Baade, Alexander and Birngruber, Reginald and Roider, Johann and Brinkmann, Ralf: Lesion strength control by automatic temperature guided retinal photocoagulation. Journal of Biomedical Optics, no. 21, pp. 098001-098001, 2016
    BibTeX Link
    @article{Schlott2016,
       author = {Schlott, Kerstin and Koinzer, Stefan and Baade, Alexander and Birngruber, Reginald and Roider, Johann and Brinkmann, Ralf},
       title = {Lesion strength control by automatic temperature guided retinal photocoagulation},
       journal = {Journal of Biomedical Optics},
       volume = {21},
       number = {9},
       pages = {098001-098001},
       note = {10.1117/1.JBO.21.9.098001},
       abstract = {Abstract.  Laser photocoagulation is an established treatment for a variety of retinal diseases. However, when using the same irradiation parameter, the size and strength of the lesions are unpredictable due to unknown inter- and intraindividual optical properties of the fundus layers. The aim of this work is to investigate a feedback system to generate desired lesions of preselectable strengths by automatically controlling the irradiation time. Optoacoustics were used for retinal temperature monitoring. A 532-nm continuous wave Nd:YAG laser was used for photocoagulation. A 75-ns/523-nm Q-switched Nd:YLF laser simultaneously excited temperature-dependent pressure transients, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. The temperature data were analyzed during the irradiation by a LabVIEW routine. The treatment laser was switched off automatically when the required lesion strength was achieved. Five different feedback control algorithms for different lesion sizes were developed and tested on rabbits in vivo. With a laser spot diameter of 133  μm, five different lesion types with ophthalmoscopically visible diameters ranging mostly between 100 and 200  μm, and different appearances were achieved by automatic exposure time control. The automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.},
       ISSN = {1083-3668},
       DOI = {10.1117/1.JBO.21.9.098001},
       year = {2016},
       type = {Journal Article}
    }
    

2015

  • Koinzer, S. and Baade, A. and Schlott, K. and Hesse, C. and Caliebe, A. and Roider, J. and Brinkmann, R.: Temperature-Controlled Retinal Photocoagulation Reliably Generates Uniform Subvisible, Mild, or Moderate Lesions. Transl Vis Sci Technol, no. 4, pp. 9, 2015
    BibTeX Link
    @article{Koinzer2015,
       author = {Koinzer, S. and Baade, A. and Schlott, K. and Hesse, C. and Caliebe, A. and Roider, J. and Brinkmann, R.},
       title = {Temperature-Controlled Retinal Photocoagulation Reliably Generates Uniform Subvisible, Mild, or Moderate Lesions},
       journal = {Transl Vis Sci Technol},
       volume = {4},
       number = {5},
       pages = {9},
       note = {Koinzer, Stefan
    Baade, Alexander
    Schlott, Kerstin
    Hesse, Carola
    Caliebe, Amke
    Roider, Johann
    Brinkmann, Ralf
    Journal article
    Transl Vis Sci Technol. 2015 Oct 6;4(5):9. eCollection 2015 Oct.},
       abstract = {PURPOSE: Conventional retinal photocoagulation produces irregular lesions and does not allow reliable control of ophthalmoscopically invisible lesions. We applied automatically controlled retinal photocoagulation, which allows to apply uniform lesions without titration, and aimed at five different predictable lesion intensities in a study on rabbit eyes. METHODS: A conventional 532-nm photocoagulation laser was used in combination with a pulsed probe laser. They facilitated real-time fundus temperature measurements and automatic exposure time control for different predefined time/temperature dependent characteristics (TTC). We applied 225 control lesions (exposure time 200 ms) and 794 TTC lesions (5 intensities, exposure times 7-800 ms) in six rabbit eyes with variable laser power (20-66.4 mW). Starting after 2 hours, we examined fundus color and optical coherence tomographic (OCT) images over 3 months and classified lesion morphologies according to a seven-stage OCT classifier. RESULTS: Visibility rates in funduscopy (OCT) after 2 hours were 17% (68%) for TTC intensity group 1, 38% (90%) for TTC group 2 and greater than 94% (>98%) for all consecutive groups. TTC groups 1 through 4 correlated to increasing morphological lesion intensities and increasing median funduscopic and OCT diameters. Group 5 lesions were as large as, but more intense than group 4 lesions. CONCLUSIONS: Automatic, temperature controlled photocoagulation allows to apply predictable subvisible, mild, or moderate lesions without manual power titration. TRANSLATIONAL RELEVANCE: The technique will facilitate standardized, automatically controlled low and early treatment of diabetic retinopathy study (ETDRS) intensity photocoagulation independently of the treating physician, the treated eye and lesion location.},
       keywords = {Oct
    animal model
    laser photocoagulation
    optoacoustics
    real-time temperature measurement
    spectral domain
    sub-visible},
       ISSN = {2164-2591 (Print)
    2164-2591},
       DOI = {10.1167/tvst.4.5.9},
       year = {2015},
       type = {Journal Article}
    }
    
  • Huttmann, Gereon and Koinzer, Stefan Otto Johannes and Müller, Heike and Ellerkamp, Iris and Baade, Alex and Moltmann, Moritz and Theisen-Kunde, Dirk and Lange, Birgit and Brinkmann, Ralf and Birngruber, Reginald: Predicting ophthalmoscopic visibility of retinal photocoagulation lesions byhigh-speedOCT: an animal studyinrabbits. Investigative Ophthalmology & Visual Science, no. 56, pp. 5980-5980, 2015
    BibTeX
    @article{Hüttmann2015,
       author = {Huttmann, Gereon and Koinzer, Stefan Otto Johannes and Müller, Heike and Ellerkamp, Iris and Baade, Alex and Moltmann, Moritz and Theisen-Kunde, Dirk and Lange, Birgit and Brinkmann, Ralf and Birngruber, Reginald},
       title = {Predicting ophthalmoscopic visibility of retinal photocoagulation lesions byhigh-speedOCT: an animal studyinrabbits},
       journal = {Investigative Ophthalmology & Visual Science},
       volume = {56},
       number = {7},
       pages = {5980-5980},
       ISSN = {1552-5783},
       year = {2015},
       type = {Journal Article}
    }
    
  • Baade, A and Schwarzer, W and Koinzer, S and Schlott, K and Birngruber, R and Brinkman, R: Power-controlled temperature guided retinal photocoagulation. in Photonic West BIOS, 2015
    BibTeX Link
    @inproceedings{Baade2015,
       author = {Baade, A and Schwarzer, W and Koinzer, S and Schlott, K and Birngruber, R and Brinkman, R},
       title = {Power-controlled temperature guided retinal photocoagulation },
       booktitle = {Photonic West BIOS},
       type = {Conference Proceedings},
    url = { https://doi.org/10.1117/12.2083042},
    year = { 2015}
    }
    

2013

  • Baade, Alexander and Schlott, Kerstin and Birngruber, Reginald and Brinkmann, Ralf: A numerical model for heat and pressure propagation for temperature controlled retinal photocoagulation. no. 8803, pp. 88030O-88030O-9, 2013
    BibTeX Link
    @inproceedings{Baade2013,
       author = {Baade, Alexander and Schlott, Kerstin and Birngruber, Reginald and Brinkmann, Ralf},
       title = {A numerical model for heat and pressure propagation for temperature controlled retinal photocoagulation},
       volume = {8803},
       pages = {88030O-88030O-9},
       note = {10.1117/12.2033590},
       abstract = {Retinal photocoagulation is an established treatment for various retinal diseases. The temperature development during a treatment can be monitored by applying short laser pulses in addition to the treatment laser light. The laser pulses induce thermoelastic pressure waves that can be detected at the cornea. We present a numerical model to examine the temperature development during the treatment as well as the formation and propagation of the ultrasonic waves. Using the model, it is possible to determine the peak temperature during retinal photocoagulation from the measured signal, and investigate the behaviour of the temperature profile and the accuracy of the temperature determination under varying conditions such as inhomogeneous pigmentation or change in irradiation parameters. It was shown that there is an uncertainty of 2.5 -9% in the determination of the peak temperature when the absorption coefficient between the absorbing layers is varied by a factor of 2. Furthermore the model was extended in order to incorporate the photoacoustic pressure generation and wave propagation. It was shown that for an irradiation pulse duration of 75 ns the resulting pressure wave energy is attenuated by 76 % due to frequency dependent attenuation in water.},
       url = {http://dx.doi.org/10.1117/12.2033590},
       type = {Conference Proceedings}, 
    year = { 2013}
    }
    

2012

  • Koinzer, S. and Schlott, K. and Ptaszynski, L. and Bever, M. and Kleemann, S. and Saeger, M. and Baade, A. and Caliebe, A. and Miura, Y. and Birngruber, R. and Brinkmann, R. and Roider, J.: Temperature-controlled retinal photocoagulation - a step toward automated laser treatment. Invest Ophthalmol Vis Sci, no. 53, pp. 3605-14, 2012
    BibTeX
    @article{Koinzer2012,
       author = {Koinzer, S. and Schlott, K. and Ptaszynski, L. and Bever, M. and Kleemann, S. and Saeger, M. and Baade, A. and Caliebe, A. and Miura, Y. and Birngruber, R. and Brinkmann, R. and Roider, J.},
       title = {Temperature-controlled retinal photocoagulation - a step toward automated laser treatment},
       journal = {Invest Ophthalmol Vis Sci},
       volume = {53},
       number = {7},
       pages = {3605-14},
       note = {Using Smart Source Parsing
    Jun 14; Print 2012 Jul},
       abstract = {Purpose. Retinal laser photocoagulation carries the risk of overtreatment due to effect variation of identically applied lesions. The degree of coagulation depends on the induced temperature increase and on exposure time. We introduce temperature controlled photocoagulation (TCP), which uses optoacoustics to determine individually exposure times necessary to create reproducible lesions. Methods. Optoacoustic temperature measurement relies on pressure waves that are excited in the retinal tissue by repetitive low-energy laser pulses. Signal amplitudes correlate with tissue temperature and are detected by a transducer in the laser contact lens. We used a continuous wave (CW) photocoagulator for treatment irradiation and superimposed probe laser pulses for simultaneous temperature measurement. Optoacoustic data of 1500 lesions (rabbit) were evaluated to develop an algorithm that controls exposure times automatically in TCP. Lesion diameters of 156 TCP lesions were compared to 156 non-controlled lesions. Histology was performed after 1 hour, and 1 and 4 weeks. Results. TCP resulted in exposure times from 4 to 800 ms depending on laser power chosen. Ophthalmoscopic and histologic lesion diameters were independent of power between 14 and 200 mW. TCP lesions barely were visible with a mean diameter equal to the treatment beam (130 mum). In contrast, standard lesion diameters increased linearly and statistically significantly with power. Histology confirmed sparing of the ganglion and nerve fiber layers in TCP. Conclusions. TCP facilitates uniform retinal lesions over a wide power range. In a clinical setting, it should generate soft and reproducible lesions independently of local tissue variation and improve safety, particularly at short exposure times.},
       year = {2012}
    }
  • Brinkmann, Ralf and Koinzer, Stefan and Schlott, Kerstin and Ptaszynski, Lars and Bever, Marco and Baade, Alexander and Luft, Susanne and Miura, Yoko and Roider, Johann and Birngruber, Reginald: Real-time temperature determination during retinal photocoagulation on patients. Journal of Biomedical Optics, no. 17, pp. 061219, 2012
    BibTeX
    @article{Brinkmann2012,
       author = {Brinkmann, Ralf and Koinzer, Stefan and Schlott, Kerstin and Ptaszynski, Lars and Bever, Marco and Baade, Alexander and Luft, Susanne and Miura, Yoko and Roider, Johann and Birngruber, Reginald},
       title = {Real-time temperature determination during retinal photocoagulation on patients},
       journal = {Journal of Biomedical Optics},
       volume = {17},
       number = {6},
       pages = {061219},
       note = {Journal Article},
       year = { 2012}
    }
  • Koinzer, Stefan and Schlott, Kerstin and Portz, Lea and Ptaszynski, Lars and Baade, Alexander and Bever, Marco and Saeger, Mark and Caliebe, Amke and Denner, Renè and Birngruber, Reginald and Brinkmann, Ralf and Roider, Johann: Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation. Journal of Biophotonics, pp. n/a-n/a, 2012
    BibTeX
    @article{Koinzer,
       author = {Koinzer, Stefan and Schlott, Kerstin and Portz, Lea and Ptaszynski, Lars and Baade, Alexander and Bever, Marco and Saeger, Mark and Caliebe, Amke and Denner, Renè and Birngruber, Reginald and Brinkmann, Ralf and Roider, Johann},
       title = {Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation},
       journal = {Journal of Biophotonics},
       pages = {n/a-n/a},
       abstract = {We conducted a study to correlate the retinal temperature rise during photocoagulation to the afterward detected tissue effect in optical coherence tomography (OCT). 504 photocoagulation lesions were examined in 20 patients. The retinal temperature increase was determined in real-time during treatment based on thermoelastic tissue expansion which was probed by repetitively applied ns laser pulses. The tissue effect was examined on fundus images and OCT images of individualized lesions. We discerned seven characteristic morphological OCT lesion classes. Their validity was confirmed by increasing visibility and diameters. Mean peak temperatures at the end of irradiation ranged from approx. 60 °C to beyond 100 °C, depending on burn intensity. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)},
       keywords = {laser photocoagulation
    optoacoustics
    photocoagulation
    retinal temperature
    spectral domain optical coherence tomography
    OCT
    subthreshold
    classification},
       year = {2012}
    }
  • Schlott, Kerstin and Koinzer, Stefan and Ptaszynski, Lars and Bever, Marco and Baade, Alex and Roider, Johann and Birngruber, Reginald and Brinkmann, Ralf: Automatic temperature controlled retinal photocoagulation. Journal of Biomedical Optics, no. 17, pp. 061223, 2012
    BibTeX Link
    @article{Schlott2012,
       author = {Schlott, Kerstin and Koinzer, Stefan and Ptaszynski, Lars and Bever, Marco and Baade, Alex and Roider, Johann and Birngruber, Reginald and Brinkmann, Ralf},
       title = {Automatic temperature controlled retinal photocoagulation},
       journal = {Journal of Biomedical Optics},
       volume = {17},
       number = {6},
       pages = {061223},
       keywords = {AutoPhoN},
       year = {2012}
    }
    

2011

  • Brinkmann, R and Koinzer, S and Schlott, K and Ptaszynski, L and Bever, M and Baade, A and Miura, Y and Birngruber, R and Roider, J: Realtime temperature determination during retinal photocoagulation on patients.. Proc SPIE, no. 7885, pp. 78850R, 2011
    BibTeX
    @article{Brinkmann2011,
       author = {Brinkmann, R and Koinzer, S and Schlott, K and Ptaszynski, L and Bever, M and Baade, A and Miura, Y and Birngruber, R and Roider, J},
       title = {Realtime temperature determination during retinal photocoagulation on patients.},
       journal = {Proc SPIE},
       volume = {7885},
       pages = {78850R},
       abstract = {Retinal photocoagulation is a long time established treatment for a variety of retinal diseases, most commonly applied for diabetic macular edema and diabetic retinopathy. The damage extent of the induced thermal coagulations depend on the temperature increase and the time of irradiation. So far, the induced temperature rise is unknown due to intraocular variations in light transmission and scattering and RPE/choroidal pigmentation, which can vary inter- and intraindividually by more than a factor of four. Thus in clinical practice, often stronger and deeper coagulations are applied than therapeutically needed, which lead to extended retinal damage and strong pain perception. The final goal of this project focuses on a dosimetry control, which automatically generates a desired temperature profile and thus coagulation strength for every individual coagulation spot, ideally unburden the ophthalmologist from any laser settings. In this paper we present the first realtime temperature measurements achieved on patients during retinal photocoagulation by means of an optoacoustic method, making use of the temperature dependence of the thermal expansion coefficient of retinal tissue. Therefore, nanosecond probe laser pulses are repetitively and simultaneously applied with the treatment radiation in order to excite acoustic waves, which are detected at the cornea with an ultrasonic transducer embedded in the contact lens and then are processed by PC.},
       url = {http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=732381},
       year = {2011},
       type = {Journal Article}
    }
    
  • Horstmann, Jens and Baade, Alexander and Brinkmann, Ralf: Photoacoustic blood vessel detection during surgical laser interventions. no. 8092, pp. 80920Z-80920Z-6, SPIE ECBO, 2011
    BibTeX Link
    @inproceedings{Horstmann2011,
       author = {Horstmann, Jens and Baade, Alexander and Brinkmann, Ralf},
       title = {Photoacoustic blood vessel detection during surgical laser interventions},
       publisher = {SPIE ECBO},
       volume = {8092},
       pages = {80920Z-80920Z-6},
       note = {10.1117/12.889635},
       abstract = {This paper presents a discussion about the potential of photoacoustics with regard to its application in surgical assistance during minimally invasive, laser assisted interventions. Aim of the work is the detection of obscured large blood vessels in order to prevent unintentional dissection. Based on spectroscopic investigations of the target tissue (liver), a wavelength for the photoacoustic excitation laser was chosen with respect to a high absorption contrast between the vessel and the surrounding liver tissue. An experimental setup featuring a simple liver model is created. Preliminary results show, that vessels with a diameter of 2 mm can be detected up to a distance of 1 mm from the treatment fibre. It is shown, that detection of acoustic waves induced inside liver is feasible over distances higher than 10 cm.},
       url = {http://dx.doi.org/10.1117/12.889635},
       type = {Conference Proceedings},
    year = { 2011}
    }
    
  • Schlott, Kerstin and Koinzer, Stefan and Ptaszynski, Lars and Luft, Susanne and Baade, Alex and Bever, Marco and Roider, Johann and Birngruber, Reginald and Brinkmann, Ralf: Optoacoustic temperature determination and automatic coagulation control in rabbits. in Ophthalmic Technologies XXI, no. 7885, Proc. SPIE, 2011
    BibTeX Link
    @inproceedings{Schlott2011,
       author = {Schlott, Kerstin and Koinzer, Stefan and Ptaszynski, Lars and Luft, Susanne and Baade, Alex and Bever, Marco and Roider, Johann and Birngruber, Reginald and Brinkmann, Ralf},
       title = {Optoacoustic temperature determination and automatic coagulation control in rabbits},
       booktitle = {Ophthalmic Technologies XXI },
       editor = {Ho, Fabrice Manns; Per G. Söderberg; Arthur},
       publisher = {Proc. SPIE},
       volume = {7885},
       note = {10.1117/12.875104},
       abstract = {Retinal laser photocoagulation is an established treatment method for many retinal diseases like macula edema or diabetic retinopathy. The selection of the laser parameters is so far based on post treatment evaluation of the lesion size and strength. Due to local pigment variations in the fundus and individual transmission the same laser parameters often lead to an overtreatment. Optoacoustic allows a non invasive monitoring of the retinal temperature increase during retinal laser irradiation by measuring the temperature dependent pressure amplitudes, which are induced by short probe laser pulses. A 75 ns/ 523 nm Nd:YLF was used as a probe laser at a repetition rate of 1 kHz, and a cw / 532 nm treatment laser for heating. A contact lens was modified with a ring-shaped ultrasonic transducer to detect the pressure waves at the cornea. Temperatures were collected for irradiations leading to soft or invisible lesions. Based on this data the threshold for denaturation was found. By analyzing the initial temperature increase, the further temperature development during irradiation could be predicted. An algorithm was found to calculate the irradiation time, which is needed for a soft lesion formation, from the temperature curve. By this it was possible to provide a real-time dosimetry by automatically switching off the treatment laser after the calculated irradiation time. Automatically controlled coagulations appear softer and more uniformly.},
       keywords = {AutoPhoN},
       url = {http://dx.doi.org/10.1117/12.875104},
       type = {Conference Proceedings},
    year = { 2011}
    }