@phdthesis{Guckenberger2003, author = {Guckenberger, Matthias}, title = {Analyse des Hitzeschocks bei Neisseria meningitidis mit DNA-Microarrays}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8952}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {Das Gram negative Bakterium Neisseria meningitidis ist weltweit ein bedeutender Erreger der bakteriellen Meningitis. Obwohl das ausschließlich humanpathogene Bakterium in bis zu 25\% der Europ{\"a}ischen Bev{\"o}lkerung die oberen Atemwege als harmloser Kommensale besiedelt, kommt es unter bestimmten, noch nicht ganz verstandenen Bedingungen zu einer klinisch manifesten Infektion. In dieser Arbeit wurde die neue Technologie der DNA Mikroarray Technologie f{\"u}r die Untersuchung des Transkriptoms bei Neisseria meningitidis etabliert. Untersucht wurde die Reaktion von N. meningitidis auf einen Hitzeschock, eine pl{\"o}tzliche Steigerung der Temperatur. W{\"a}hrend einer Infektion wird das Bakterium durch induziertes Fieber sehr {\"a}hnlichen Bedingungen ausgesetzt. Im Ergebnis erlaubten die RNA Expressionsanalysen nicht nur eine sichere Unterscheidung deregulierter Gene von Genen mit konstanter Expression, sondern es konnte auch das Ausmaß der Deregulation exakt bestimmt werden. Die Daten der DNA Mikroarray Experimente wurden mit der etablierten Technik der RT-PCR exakt best{\"a}tigt. Bei den Hitzeschock-Versuchen mit Neisseria meningitidis konnten zahlreiche ORFs als Hitzeschock-Gene identifiziert werden. Die Funktion dieser Gene, darunter groEL/groES und dnaJ/dnaK, war bereits bei anderen Organismen beschrieben worden, was die Qualit{\"a}t und Reproduzierbarkeit der Ergebnisse unterstreicht. Es konnte gezeigt werden, dass die Intensit{\"a}t des Hitzeschocks und damit die Deregulation der Hitzeschock-Gene mit steigender Temperatur zunimmt. Eine Erkl{\"a}rung f{\"u}r dieses interessante Ergebnis w{\"a}re, dass mit Steigerung der Temperatur der Schaden im Bakterium zunimmt und dadurch auch mehr Hitzeschock Proteine zur Reparatur ben{\"o}tigt werden. Daneben wurde erstmals die transkriptionelle Beeinflussung von Genen aus dem Bereich der Transformation durch einen Hitzeschock gefunden. Diese Daten konnten durch einen ph{\"a}notypischen Nachweis der Verminderung der Transformationsaktivit{\"a}t von Meningokokken nach einem Hitzeschock best{\"a}tigt werden. Diese neue Technik wird eine der Schl{\"u}sseltechnologien f{\"u}r die Forschung in der postgenomischen {\"A}ra sein. Viele Fragen in dem noch l{\"u}ckenhaften Wissen {\"u}ber die Pathologie von Neisseria meningitidis sollen sich in Zukunft mit Hilfe der DNA Mikroarrays beantworten lassen.}, language = {de} } @article{GersztenSahgalSheehanetal.2013, author = {Gerszten, Peter C. and Sahgal, Arjun and Sheehan, Jason P. and Kersh, Ronald and Chen, Stephanie and Flickinger, John C. and Quader, Mubina and Fahim, Daniel and Grills, Inga and Shin, John H. and Winey, Brian and Oh, Kevin and Sweeney, Reinhart A. and Guckenberger, Matthias}, title = {A multi-national report on methods for institutional credentialing for spine radiosurgery}, series = {Radiation Oncology}, volume = {8}, journal = {Radiation Oncology}, number = {158}, doi = {10.1186/1748-717X-8-158}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131485}, year = {2013}, abstract = {Background: Stereotactic body radiotherapy and radiosurgery are rapidly emerging treatment options for both malignant and benign spine tumors. Proper institutional credentialing by physicians and medical physicists as well as other personnel is important for the safe and effective adoption of spine radiosurgery. This article describes the methods for institutional credentialing for spine radiosurgery at seven highly experienced international institutions. Methods: All institutions (n = 7) are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided spine radiosurgery. A questionnaire consisting of 24 items covering various aspects of institutional credentialing for spine radiosurgery was completed by all seven institutions. Results: Close agreement was observed in most aspects of spine radiosurgery credentialing at each institution. A formal credentialing process was believed to be important for the implementation of a new spine radiosurgery program, for patient safety and clinical outcomes. One institution has a written policy specific for spine radiosurgery credentialing, but all have an undocumented credentialing system in place. All institutions rely upon an in-house proctoring system for the training of both physicians and medical physicists. Four institutions require physicians and medical physicists to attend corporate sponsored training. Two of these 4 institutions also require attendance at a non-corporate sponsored academic society radiosurgery course. Corporate as well as non-corporate sponsored training were believed to be complimentary and both important for training. In 5 centers, all cases must be reviewed at a multidisciplinary conference prior to radiosurgery treatment. At 3 centers, neurosurgeons are not required to be involved in all cases if there is no evidence for instability or spinal cord compression. Backup physicians and physicists are required at only 1 institution, but all institutions have more than one specialist trained to perform spine radiosurgery. All centers believed that credentialing should also be device specific, and all believed that professional societies should formulate guidelines for institutions on the requirements for spine radiosurgery credentialing. Finally, in 4 institutions radiation therapists were required to attend corporate-sponsored device specific training for credentialing, and in only 1 institution were radiation therapists required to also attend academic society training for credentialing. Conclusions: This study represents the first multi-national report of the current practice of institutional credentialing for spine radiosurgery. Key methodologies for safe implementation and credentialing of spine radiosurgery have been identified. There is strong agreement among experienced centers that credentialing is an important component of the safe and effective implementation of a spine radiosurgery program.}, language = {en} } @article{HardcastleTomeCannonetal.2012, author = {Hardcastle, Nicholas and Tom{\´e}, Wolfgang A. and Cannon, Donald M. and Brouwer, Charlotte L. and Wittendorp, Paul W. H. and Dogan, Nesrin and Guckenberger, Matthias and Allaire, St{\´e}phane and Mallya, Yogish and Kumar, Prashant and Oechsner, Markus and Richter, Anne and Song, Shiyu and Myers, Michael and Polat, B{\"u}lent and Bzdusek, Karl}, title = {A multi-institution evaluation of deformable image registration algorithms for automatic organ delineation in adaptive head and neck radiotherapy}, series = {Radiation Oncology}, volume = {7}, journal = {Radiation Oncology}, number = {90}, doi = {10.1186/1748-717X-7-90}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134756}, year = {2012}, abstract = {Background: Adaptive Radiotherapy aims to identify anatomical deviations during a radiotherapy course and modify the treatment plan to maintain treatment objectives. This requires regions of interest (ROIs) to be defined using the most recent imaging data. This study investigates the clinical utility of using deformable image registration (DIR) to automatically propagate ROIs. Methods: Target (GTV) and organ-at-risk (OAR) ROIs were non-rigidly propagated from a planning CT scan to a per-treatment CT scan for 22 patients. Propagated ROIs were quantitatively compared with expert physician-drawn ROIs on the per-treatment scan using Dice scores and mean slicewise Hausdorff distances, and center of mass distances for GTVs. The propagated ROIs were qualitatively examined by experts and scored based on their clinical utility. Results: Good agreement between the DIR-propagated ROIs and expert-drawn ROIs was observed based on the metrics used. 94\% of all ROIs generated using DIR were scored as being clinically useful, requiring minimal or no edits. However, 27\% (12/44) of the GTVs required major edits. Conclusion: DIR was successfully used on 22 patients to propagate target and OAR structures for ART with good anatomical agreement for OARs. It is recommended that propagated target structures be thoroughly reviewed by the treating physician.}, language = {en} } @article{ColvillBoothNilletal.2016, author = {Colvill, Emma and Booth, Jeremy and Nill, Simeon and Fast, Martin and Bedford, James and Oelfke, Uwe and Nakamura, Mitsuhiro and Poulsen, Per and Worm, Esben and Hansen, Rune and Ravkilde, Thomas and Rydh{\"o}g, Jonas Scherman and Pommer, Tobias and af Rosenschold, Per Munck and Lang, Stephanie and Guckenberger, Matthias and Groh, Christian and Herrmann, Christian and Verellen, Dirk and Poels, Kenneth and Wang, Lei and Hadsell, Michael and Sothmann, Thilo and Blanck, Oliver and Keall, Paul}, title = {A dosimetric comparison of real-time adaptive and non-adaptive radiotherapy: a multi-institutional study encompassing robotic, gimbaled, multileaf collimator and couch tracking}, series = {Radiotherapy and Oncology}, volume = {119}, journal = {Radiotherapy and Oncology}, number = {1}, doi = {10.1016/j.radonc.2016.03.006}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189605}, pages = {159-165}, year = {2016}, abstract = {Purpose: A study of real-time adaptive radiotherapy systems was performed to test the hypothesis that, across delivery systems and institutions, the dosimetric accuracy is improved with adaptive treatments over non-adaptive radiotherapy in the presence of patient-measured tumor motion. Methods and materials: Ten institutions with robotic(2), gimbaled(2), MLC(4) or couch tracking(2) used common materials including CT and structure sets, motion traces and planning protocols to create a lung and a prostate plan. For each motion trace, the plan was delivered twice to a moving dosimeter; with and without real-time adaptation. Each measurement was compared to a static measurement and the percentage of failed points for gamma-tests recorded. Results: For all lung traces all measurement sets show improved dose accuracy with a mean 2\%/2 mm gamma-fail rate of 1.6\% with adaptation and 15.2\% without adaptation (p < 0.001). For all prostate the mean 2\%/2 mm gamma-fail rate was 1.4\% with adaptation and 17.3\% without adaptation (p < 0.001). The difference between the four systems was small with an average 2\%/2 mm gamma-fail rate of <3\% for all systems with adaptation for lung and prostate. Conclusions: The investigated systems all accounted for realistic tumor motion accurately and performed to a similar high standard, with real-time adaptation significantly outperforming non-adaptive delivery methods.}, language = {en} }