@article{Franke2013,
   author = {Franke, Gesa Lilith and Hillmann, Dierck and Lührs, Christian and Koch, Peter and Wollenzin, Jörn and Hüttmann, Gereon},
   title = {Towards microscopic resolution in holoscopy},
   pages = {85711O-85711O},
   note = {10.1117/12.2006806},
   abstract = {Holoscopy is a new imaging approach combining digital holography and full-field Fourier-domain optical coherence tomography. The interference pattern between light scattered by a sample and a defined reference wave is recorded and processed numerically. During reconstruction numerical refocusing is applied, overcoming the limitation of the focal depth and thus a uniform, diffraction limited lateral resolution over the whole measurement depth can be obtained. The advantage of numerical refocusing becomes especially significant for imaging at high numerical apertures (NAs). We use a high-resolution setup based on a Mach-Zehnder interferometer with an high-resolution microscope objective (NA = 0.75). For reliable reconstruction of a sample volume the Rayleigh length of the microscope objective and the axial resolution, given by the spectral range of the light source, need to be matched. For a 0.75 NA objective a tunable light source with a sweeping range of ! 300nm is required. Here we present as a first step a tunable Ti:sapphire laser with a tuning range of 187 nm. By characterizing the spectral properties of the Ti:sapphire laser and determining the axial point spread function we demonstrate the feasibility of this light source for high-resolution holoscopy.},
   DOI = {10.1117/12.2006806},
   url = {http://dx.doi.org/10.1117/12.2006806},
   year = {2013},
   type = {Journal Article}
}

@misc{Miura2013,
   author = {Miura, Y and Huettmann, G and Orzekowsky-Schroeder, R and Steven, P and Szaszák, M and Koop, N and Brinkmann, R },
   title = {Two-photon Microscopy and Fluorescence Lifetime Analysis of Lipid Peroxidation Product in Photoreceptor Outer Segment and in Retinal Pigment Epithelial Cell},
   publisher = {ARVO Meeting Abstracts},
   month = {March 26, 2012 },
   url = {http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=57630548-893d-4e45-9ddc-b6f547dd4ff0&cKey=d08a30bc-fe98-40a2-8a1c-1b171e4becd3&mKey=f0fce029-9bf8-4e7c-b48e-9ff7711d4a0e},
   year = {2013},
   type = {Poster}
}

@article{Müller2012,
   author = {Mueller, H. H. and Ptaszynski, L. and Schlott, K. and Debbeler, C. and Bever, M. and Koinzer, S. and Birngruber, R. and Brinkmann, R. and Huettmann, G.},
   title = {Imaging thermal expansion and retinal tissue changes during photocoagulation by high speed OCT},
   journal = {Biomedical Optics Express},
   volume = {3},
   number = {5},
   pages = {1025-1046},
   note = {935RH
Times Cited:8
Cited References Count:37},
   abstract = {Visualizing retinal photocoagulation by real-time OCT measurements may considerably improve the understanding of thermally induced tissue changes and might enable a better reproducibility of the ocular laser treatment. High speed Doppler OCT with 860 frames per second imaged tissue changes in the fundus of enucleated porcine eyes during laser irradiation. Tissue motion, measured by Doppler OCT with nanometer resolution, was correlated with the temperature increase, which was measured non-invasively by optoacoustics. In enucleated eyes, the increase of the OCT signal near the retinal pigment epithelium (RPE) corresponded well to the macroscopically visible whitening of the tissue. At low irradiance, Doppler OCT revealed additionally a reversible thermal expansion of the retina. At higher irradiance additional movement due to irreversible tissue changes was observed. Measurements of the tissue expansion were also possible in vivo in a rabbit with submicrometer resolution when global tissue motion was compensated. Doppler OCT may be used for spatially resolved measurements of retinal temperature increases and thermally induced tissue changes. It can play an important role in understanding the mechanisms of photocoagulation and, eventually, lead to new strategies for retinal laser treatments. (c) 2012 Optical Society of America},
   keywords = {optical coherence tomography
laser photocoagulation
vein occlusion
management
diseases
fundus
blood},
   ISSN = {2156-7085},
   url = {<Go to ISI>://WOS:000303537400018},
   year = {2012},
   type = {Journal Article}
}

@article{Gehlsen,
   author = {Gehlsen, U. and Oetke, A. and Szaszak, M. and Koop, N. and Paulsen, F. and Gebert, A. and Huettmann, G. and Steven, P.},
   title = {Two-photon fluorescence lifetime imaging monitors metabolic changes during wound healing of corneal epithelial cells in vitro},
   journal = {Graefes Arch Clin Exp Ophthalmol},
   volume = {6},
   pages = {6},
   note = {Using Smart Source Parsing
May},
   abstract = {BACKGROUND: Early and correct diagnosis of delayed or absent corneal epithelial wound healing is a key factor in the prevention of infection and consecutive destruction of the corneal stroma with impending irreversible visual loss. Two-photon microscopy (TPM) is a novel technology that has potential to depict epithelial cells and to evaluate cellular function by measuring autofluorescence properties such as fluorescence intensity and fluorescence lifetimes of metabolic co-factors such as NAD(P)H. METHODS: Using non-invasive TPM in a tissue-culture scratch model and an organ-culture erosion model, fluorescence intensity and fluorescence lifetimes of NAD(P)H were measured before and during closure of the epithelial wounds. Influence of temperature and selective inhibition of metabolism on intensity and lifetimes were tested additionally. RESULTS: Decrease of temperature resulted in significant increase of fluorescence lifetimes and decrease of the relative amount of free NAD(P)H due to decreased global metabolism. Increase in temperature and upregulation of glycolysis through blocking the mitochondrial electron transport chain by rotenone resulted in increased intensity, decreased lifetimes and increase in the relative amount of free NAD(P)H. Changes of lifetimes and free:protein-bound NAD(P)H ratios were similar to changes measured during wound healing in both scratch and erosion models. CONCLUSIONS: Fluorescence lifetime measurements (FLIM) detected enhancement of cellular metabolism following epithelial damage in both models. The prospective detection of cellular autofluorescence in vivo, in particular FLIM of metabolic cofactor NAD(P)H, has the potential to become an indispensible tool in clinical use to differentiate healing from non-healing epithelial cells and to evaluate effects of newly developed substances on cellular metabolism in preclinical and clinical trials.},
   year = {2012}
}

@inproceedings{Xie,
   author = {Xie, Y. and Bonin, T. and Loeffler, S. and Huettmann, G. and Tronnier, V. and Hofmann, U. G.},
   title = {Fiber spectral domain optical coherence tomography for in vivo rat brain imaging},
   editor = {Jurgen, Popp and Wolfgang, Drexler and Valery, V. Tuchin and Dennis, L. Matthews},
   publisher = {SPIE},
   volume = {7715},
   pages = {77152F},
year = { 2010},
URL = { https://doi.org/10.1117/12.854798}

}

@article{Müller-2010,
   author = {Mueller, M. and Schulz-Wackerbarth, C. and Steven, P. and Lankenau, E. and Bonin, T. and Mueller, H. and Brueggemann, A. and Birngruber, R. and Grisanti, S. and Huettmann, G.},
   title = {Slit-lamp-adapted fourier-domain OCT for anterior and posterior segments: preliminary results and comparison to time-domain OCT},
   journal = {Curr Eye Res},
   volume = {35(8)},
 DOI = { 10.3109/02713683.2010.481069},
year = { 2010},
   pages = {722-32},
   note = {Using Smart Source Parsing
Aug},
   abstract = {PURPOSE: To evaluate the diagnostic potential of a slit-lamp (SL)-adapted Fourier-domain (= spectral radar, SR) optical coherence tomography (OCT)-SL-SR-OCT-instrument as an in vivo imaging device for use in examinations of the anterior and posterior segments. MATERIALS AND METHODS: In a pilot study, 88 eyes from 70 healthy volunteers and patients were examined using a prototype Fourier-domain SL-SR-OCT system. Results were compared to those from the following commercially available systems: the 1310-nm SL-OCT (Heidelberg Engineering, Heidelberg, Germany) for anterior segment and the Stratus OCT (Zeiss Meditec, Jena, Germany) for posterior segment imaging. Our SL-SR-OCT provides 1025 axial scans, 5000 Hz line-scan frequency, scan length of up to 8 mm, axial depth in air of 3.5 mm, and resolution of 9 mum. For posterior visualization, a hand-held 78-diopter ophthalmoscopic lens was used. RESULTS: Our SL-SR-OCT system allowed simultaneous scanning with direct biomicroscopic and SL imaging of anterior and posterior segment structures. Anatomical structures and pathological changes were displayed with high resolution and excellent contrast. Measurements of corneal and retinal thickness were possible. In comparison to images obtained by the SL-OCT, our SL-SR-OCT boasted a higher resolution, thus providing more clinically relevant details of the corneal epithelium, internal structure of filtering blebs, etc. Complete imaging of the chamber angle was limited, however, due to the backscattering properties of the sclera at 830 nm. For posterior segment imaging, excellent delineation of the macula and optic nerve head details, with a distinct portrayal of macular pathology and retinal edema, was possible with SL-SR-OCT. CONCLUSION: SL-SR-OCT enables detailed imaging of physiological and pathological anterior and posterior segment structures. As a multi-purpose device, it offers a wide spectrum of applications, with high-quality OCT-imaging, in a comfortable setting without the need to move the patient.},
  
}

@article{Gasca,
   author = {Gasca, F. and Ramrath, L. and Huettmann, G. and Schweikard, A.},
   title = {Automated segmentation of tissue structures in optical coherence tomography data},
   journal = {J Biomed Opt},
   volume = {14},
   number = {3},
   pages = {034046},
   note = {Using Smart Source Parsing
May-Jun},
   abstract = {Segmentation of optical coherence tomography (OCT) images provides useful information, especially in medical imaging applications. Because OCT images are subject to speckle noise, the identification of structures is complicated. Addressing this issue, two methods for the automated segmentation of arbitrary structures in OCT images are proposed. The methods perform a seeded region growing, applying a model-based analysis of OCT A-scans for the seed's acquisition. The segmentation therefore avoids any user-intervention dependency. The first region-growing algorithm uses an adaptive neighborhood homogeneity criterion based on a model of an OCT intensity course in tissue and a model of speckle noise corruption. It can be applied to an unfiltered OCT image. The second performs region growing on a filtered OCT image applying the local median as a measure for homogeneity in the region. Performance is compared through the quantitative evaluation of artificial data, showing the capabilities of both in terms of structures detected and leakage. The proposed methods were tested on real OCT data in different scenarios and showed promising results for their application in OCT imaging.},
   year = {2009}
}

@article{Yao,
   author = {Yao, C and Qu, X. and Zhang, Z. and B., Yao and Hüttmann, G and Rahmanzadeh, R.},
   title = {Influence of Laser Parameters on Membrane Permeability with Nanoparticles and Targeted Antibody Transfection},
   journal = {J Biomed Opt},
   volume = {14},
   pages = {054034},
   note = {Journal article},
   year = {2009}
}

@inproceedings{Just-2008,
   author = {Just, T. and Lankenau, E. and Huettmann, G. and Pau, H.W.},
   title = {Optical coherence tomography as a guide for cochlear implant surgery},
   booktitle = {Progress in Biomedical Optics and Imaging},
   editor = {Nikiforos, K. and Bernard, C. and Haishan, Z.},
   publisher = {SPIE 6842},
   pages = {F1-F6},
url = { https://doi.org/10.1117/12.771446},
year = { 2008}

}

@article{Mueller2008,
   author = {Mueller, M. and Huettmann, G. and Koop, N. and Steven, P.},
   title = {Minimal-Invasive Imaging of Ocular Surface Pathologies - Confocal vs. Two-Photon Microscopy},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {49},
   number = {13},
   pages = {2258-2258},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2008},
   type = {Journal Article}
}

@article{Ramrath,
   author = {Ramrath, L. and Moreno, G. and Mueller, H. and Bonin, T. and Huettmann, G. and Schweikard, A.},
   title = {Towards multi-directional OCT for speckle noise reduction},
   journal = {Med Image Comput Comput Assist Interv},
   volume = {11},
   number = {Pt 1},
   pages = {815-23},
   note = {Using Smart Source Parsing},
   abstract = {Multi-directional optical coherence tomography (MD-OCT) applies and extends the concept of angular compounding for speckle noise reduction to the area of OCT imaging. OCT images are acquired from a wide range of angles of view. Averaging of the rotated images therefore requires compensation of the parallax which is achieved by simple image registration for image reconstruction. Test measurements of a sample structure in a low and highly scattering environment show that the method improves the signal-to-noise ratio by a factor of 4 and hence reduces speckle noise significantly. Experimental results also show that the proposed averaging increases the performance of common edge-detection algorithms.},
   year = {2008}
}

@article{Yao,
   author = {Yao, C. P. and Zhang, Z. X. and Rahmanzadeh, R. and Huettmann, G.},
   title = {Laser-based gene transfection and gene therapy},
   journal = {IEEE Trans Nanobioscience},
   volume = {7},
   number = {2},
   pages = {111-9},
   note = {Yao, C P
Zhang, Z X
Rahmanzadeh, R
Huettmann, G
Research Support, Non-U.S. Gov't
Review
United States
IEEE Trans Nanobioscience. 2008 Jun;7(2):111-9.},
   abstract = {The plasma membrane of mammalian cells can be transiently permeablized by optical means and exogenous materials or genes can be introduced into the cytoplasm of living cells. Until now, few mechanisms were exploited for the manipulation: laser is directly and tightly focused on the cells for optoinjection, laser-induced stress waves, photochemical internalization, and irradiation of selective cell targeting with light-absorbing particles. During the past few years, extensive progress and numerous breakthroughs have been made in this area of research. This review covers four different laser-assisted transfection techniques and their advantages and disadvantages. Universality towards various cell lines is possibly the main advantage of laser-assisted optoporation in comparison with presently existing methods of cell transfection.},
   keywords = {Cell Membrane/ radiation effects
DNA/ administration & dosage/ pharmacokinetics
Gene Therapy/ methods
Lasers
Transfection/ methods},
   year = {2008}
}

@misc{Qu,
   author = {Qu, X. and Wang, J. and Zhang, Z. and Koop, N. and Rahmanzadeh, R. and Huttmann, G.},
   title = {Imaging of cancer cells by multiphoton microscopy using gold nanoparticles and fluorescent dyes},
   volume = {13},
   number = {3},
   pages = {031217},
   note = {Using Smart Source Parsing
May-Jun},
   abstract = {Due to their unique optical properties, optical probes, including metal nanoparticles (NPs) and fluorescent dyes, are increasingly used as labeling tools in biological imaging. Using multiphoton microscopy and fluorescence lifetime imaging (FLIM) at 750-nm excitation, we recorded intensity and FLIM images from gold NPs (30 nm) and the fluorescent dye Alexa 488 (A488) conjugated with monoclonal ACT-1 antibodies as well as Hoechst 33258 (H258) after incubation with the lymphoma cell line (Karpas-299). From the FLIM images, we can easily discriminate the imaging difference between cells and optical probes according to their distinct fluorescence lifetimes (cellular autofluorescence: 1 to 2 ns; gold NPs: <0.02 ns; A488: 3.5 ns; H258: 2.5 ns). The NP-ACT-1 and A488-ACT-1 conjugates were bound homogeneously on the surface of cells, whereas H258 stained the cell nucleus. We demonstrate that the emission intensity of gold NPs is about ten times stronger than that of the autofluorescence of Karpas-299 cells at the same excitation power. Compared with fluorescent dyes, stronger emission is also observed from gold NPs. Together with their high photostability, these observations suggest that gold NPs are a viable alternative to fluorescent dyes for cellular imaging and cancer diagnosis.},
   ISBN = {1083-3668 (Print)
1083-3668 (Linking)},
   year = {2008}
}

@article{Rahmanzadeh,
   author = {Rahmanzadeh, R. and Huttmann, G. and Gerdes, J. and Scholzen, T.},
   title = {Chromophore-assisted light inactivation of pKi-67 leads to inhibition of ribosomal RNA synthesis},
   journal = {Cell Prolif},
   volume = {40},
   number = {3},
   pages = {422-30},
   note = {Rahmanzadeh, R
Huttmann, G
Gerdes, J
Scholzen, T
England
Cell Prolif. 2007 Jun;40(3):422-30.},
   abstract = {OBJECTIVES: Expression of the nuclear Ki-67 protein (pKi-67) is strongly associated with cell proliferation. For this reason, antibodies against this protein are widely used as prognostic tools for the assessment of cell proliferation in biopsies from cancer patients. Despite this broad application in histopathology, functional evidence for the physiological role of pKi-67 is still missing. Recently, we proposed a function of pKi-67 in the early steps of ribosomal RNA (rRNA) synthesis. Here, we have examined the involvement of pKi-67 in this process by photochemical inhibition using chromophore-assisted light inactivation (CALI). MATERIALS AND METHODS: Anti-pKi-67 antibodies were labelled with the fluorochrome fluorescein 5(6)-isothiocyanate and were irradiated after binding to their target protein. RESULTS: Performing CALI in vitro on cell lysates led to specific cross-linking of pKi-67. Moreover, the upstream binding factor (UBF) necessary for rRNA transcription was also partly subjected to cross-link formation, indicating a close spatial proximity of UBF and pKi-67. CALI in living cells, using micro-injected antibody, caused a striking relocalization of UBF from foci within the nucleoli to spots located at the nucleolar rim or within the nucleoplasm. pKi-67-CALI resulted in dramatic inhibition of RNA polymerase I-dependent nucleolar rRNA synthesis, whereas RNA polymerase II-dependent nucleoplasmic RNA synthesis remained almost unaltered. CONCLUSIONS: Our data presented here argue for a crucial role of pKi-67 in RNA polymerase I-dependent nucleolar rRNA synthesis.},
   keywords = {Antibodies, Antinuclear
Antibodies, Monoclonal
Cell Division/physiology
Cell Nucleolus/physiology
Fluorescein-5-isothiocyanate
Fluorescent Dyes
HeLa Cells
Humans
Ki-67 Antigen/*genetics/*metabolism
Photochemistry
RNA Polymerase I/metabolism
RNA, Ribosomal/*biosynthesis},
   year = {2007}
}

@article{Steven2007,
   author = {Steven, P. and Rupp, J. and Huettmann, G. and Koop, N. and Laqua, H.},
   title = {Two-Photon Real-Time Imaging of Conjunctiva-Associated Lymphoid Tissue (CALT)},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {48},
   number = {13},
   pages = {201-201},
   abstract = {AbstractPurpose:: Immunological real-time analysis of conjunctiva-associated lymphoid tissue (CALT) is challenging at state. For the first time, two-photon microscopy, a new optical method, is evaluated in its use to analyze morphology and function of CALT. Methods:: Conjunctiva of female Balb/c mice is challenged with Chlamydia trachomatis serovar C (ChtC) or ovalbumin and choleratoxin subunit B (OVA/CTB) for CALT induction. A two-photon microscope equipped with a near infrared femtosecond-laser and a fluorescence-lifetime detector is used for ex-vivo analysis of unfixed and unstained ocular tissue with additional application of fluorescent microspheres to demonstrate transepithelial particle transport. Results:: Challenge with ChtC or OVA/CTB induce all CALT components (lymphoepithelium, follicles, blood and lymphatic vessels), that are demonstrated in cellular and subcellular resolution by means of autofluorescence imaging. Wavelength adaptation allows specific differentiation of cellular and acellular components. Fluorescence-lifetime detection permits differentiation of cellular subsets (e.g. lymphocytes and macrophages). Application of fluorescent microspheres demonstrates transepithelial particle transport and detection within intracellular vesicles. Conclusions:: Two-photonmicroscopy is an innovative optical technique to analyse morphological and functional features of CALT. Detection of transepithelial particle transport and its impact on conjunctival immunological processes can be visualized in real-time. Future in-vivo experiments with suitable animal models would allow detailed analysis of CALT in a clinical context e.g. corneal transplant rejection, keratoconjunctivitis sicca and follicular conjunctivitis.},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2007},
   type = {Journal Article}
}

@article{Yao,
   author = {Yao, C. and Rahmanzadeh, R. and Endl, E. and Zhang, Z. and Gerdes, J. and Huttmann, G.},
   title = {Elevation of plasma membrane permeability by laser irradiation of selectively bound nanoparticles},
   journal = {J Biomed Opt},
   volume = {10},
   number = {6},
   pages = {064012},
   note = {Yao, Cuiping
Rahmanzadeh, Ramtin
Endl, Elmar
Zhang, Zhenxi
Gerdes, Johannes
Huttmann, Gereon
Research Support, Non-U.S. Gov't
United States
J Biomed Opt. 2005 Nov-Dec;10(6):064012.},
   abstract = {Irradiation of nanoabsorbers with pico- and nanosecond laser pulses could result in thermal effects with a spatial confinement of less than 50 nm. Therefore absorbing nanoparticles could be used to create controlled cellular effects. We describe a combination of laser irradiation with nanoparticles, which changes the plasma membrane permeability. We demonstrate that the system enables molecules to penetrate impermeable cell membranes. Laser light at 532 nm is used to irradiate conjugates of colloidal gold, which are delivered by antibodies to the plasma membrane of the Hodgkin's disease cell line L428 and/or the human large-cell anaplastic lymphoma cell line Karpas 299. After irradiation, membrane permeability is evaluated by fluorescence microscopy and flow cytometry using propidium iodide (PI) and fluorescein isothiocyanate (FITC) dextran. The fraction of transiently permeabilized and then resealed cells is affected by the laser parameter, the gold concentration, and the membrane protein of the different cell lines to which the nanoparticles are bound. Furthermore, a dependence on particle size is found for these interactions in the different cell lines. The results suggest that after optimization, this method could be used for gene transfection and gene therapy.},
   keywords = {Biopolymers/pharmacokinetics
Cell Line, Tumor
Cell Membrane Permeability/ physiology/ radiation effects
Drug Delivery Systems/ methods
Fluoresceins/ pharmacokinetics
Humans
Lasers
Lymphoma/ metabolism
Nanostructures},
   year = {2005}
}

@inproceedings{Koch-2004,
   author = {Koch, Peter and Huettmann, Gereon and Schleiermacher, Hansfrieder and Eicholz, Joerg and Koch, Edmund},
   title = {Linear OCT system with down conversion of the fringe pattern},
   editor = {Valery, V. Tuchin and Joseph, A. Izatt and James, G. Fujimoto},
   publisher = {SPIE},
   volume = {5316},
   pages = {260-267},
Year = { 2004},
URL = { https://doi.org/10.1117/12.531323}

}

@inproceedings{Hüttmann2003,
   author = {Huettmann, Gereon and Radt, Benno and Serbin, Jesper and Birngruber, Reginald},
   title = {Inactivation of proteins by irradiation of gold nanoparticles with nano- and picosecond laser pulses},
   editor = {Rudolf, W. Steiner},
   publisher = {SPIE},
   volume = {5142},
   pages = {88-95},
URL = { https://doi.org/10.1364/ECBO.2003.5142_88},
year = { 2003}
}

@inproceedings{Schuele-2002,
   author = {Schuele, Georg and Huettmann, Gereon and Brinkmann, Ralf},
   title = {Noninvasive temperature measurements during laser irradiation of the retina with optoacoustic techniques},
   editor = {Fabrice, Manns and Per, G. Soederberg and Arthur, Ho},
   publisher = {Proc. SPIE},
   volume = {4611},
   pages = {64-71},
year = { 2002},
url = { https://doi.org/10.1117/12.470601} 
}

@inproceedings{Lange2001,
   author = {Lange, Bjoern I. and Radt, Benno and Huettmann, Gereon},
   title = {Cr,Tm,Ho: YAG laser amplifier},
   editor = {Richard, Scheps},
   publisher = {SPIE},
   volume = {4267},
   pages = {169-174},
URL = {https://doi.org/10.1117/12.424616},
Year = { 2001}
}

@inproceedings{Radt-2001,
   author = {Radt, Benno and Serbin, Jesper and Lange, Bjoern I. and Birngruber, Reginald and Huettmann, Gereon},
   title = {Laser-generated micro- and nanoeffects: inactivation of proteins coupled to gold nanoparticles with nano- and picosecond pulses},
   editor = {Reginald, Birngruber and Hubert van den, Bergh},
   publisher = {SPIE},
   volume = {4433},
   pages = {16-24},
year = { 2001},
URL = { https://doi.org/10.1117/12.446518}

}

@article{Eichenauer,
   author = {Eichenauer, Rolf H. and Huettmann, Gereon and Woermer, Stephan and Koop, Norbert and Beyer, Wolfgang and Jocham, Dieter},
   title = {New balloon catheter system used for PDT in the human urinary bladder: accuracy of light distribution},
   pages = {138-144},
   note = {10.1117/12.308141},
   abstract = {Photodynamic therapy (PDT) may provide a new approach for treatment of patients with superficial transitional carcinoma and carcinoma in situ of the bladder. The light applicator for the bladder wall (Rusch) is constructed as a balloon catheter with two concentric balloons. A new PDT applicator (Rusch) was assessed for the homogeneity and accuracy of irradiation during PDT. In an in-vitro experiment with 17 freshly harvested porcine bladders the fluence rate was measured locally with isotropic detectors. The results were compared to the light fluence detected by the PDT applicator. The increase of the fluence rate (beta) inside the bladders due to back scattering ranged between 5.3 and 7.0 with an average of 6.2. Local variations of the fluence rate in the spherical bladders were also smaller than 15%. Therefore it is concluded, that a homogeneous and accurate irradiation during PDT is possible. Blood between the outer balloon and the bladder wall reduces the local fluence rate strongly and should to be avoided. Also larger air bubbles in the applicator can lead to an inhomogeneous light distribution. In regular application the presented new catheter system provides accurate and easy light dosimetry during PDT of the bladder. Attention had to be paid to a continuous flushing of the space between balloon and bladder wall in order to prevent the accumulation of urine and blood. To avoid a malfunction of the system and large errors in light dosimetry and application, it is advisable to monitor the measured light dosage and the shape of the balloon using ultrasonography during PDT.},
   year = {1998}
}