There is an increasing interest in chromophores absorbing and emitting in the near-infrared (NIR) spectral region, e.g., for applications as fluorescent reporters for optical imaging techniques and hence, in reliable methods for the characterization of their signal-relevant properties like the fluorescence quantum yield (Φ(f)) and brightness. The lack of well established Φ(f) standards for the NIR region in conjunction with the need for accurate Φ(f) measurements in transparent and scattering media encouraged us to built up an integrating sphere setup for spectrally resolved measurements of absolute fluorescence traceable to radiometric scales. Here, we present the design of this setup and its characterization and validation including an uncertainty budget for the determination of absolute Φ(f) in the visible and NIR. To provide the basis for better measurements of Φ(f) in the spectral window from ca. 600 to 1000 nm used, e.g., for optical imaging, the absolute Φ(f) of a set of NIR chromophores covering this spectral region are measured and compared to relative values obtained using rhodamine 101 as Φ(f) standard. Additionally, the absolute Φ(f) values of some red dyes that are among the most commonly used labels in the life sciences are presented as well as the absolute quantum yield of an optical probe for tumor imaging.

The commercial availability of stand-alone setups for the determination of absolute photoluminescence quantum yields (Phi(f)) in conjunction with the increasing use of integrating sphere accessories for spectrofluorometers is expected to have a considerable influence not only on the characterization of chromophore systems for use in optical and opto-electronic devices, but also on the determination of this key parameter for (bio)analytically relevant dyes and functional luminophores. Despite the huge potential of systems measuring absolute Phi(f) values and the renewed interest in dependable data, evaluated protocols for even the most elementary case, the determination of the fluorescence quantum yield of transparent dilute solutions of small organic dyes with integrating sphere methods, are still missing. This encouraged us to evaluate the performance and sources of uncertainty of a simple commercial integrating sphere setup with dilute solutions of two of the best characterized fluorescence quantum yield standards, quinine sulfate dihydrate and rhodamine 101, strongly differing in spectral overlap between absorption and emission. Special attention is dedicated to illustrate common pitfalls of this approach, thereby deriving simple procedures to minimize measurement uncertainties and improve the comparability of data for the broad community of users of fluorescence techniques.

Imaging and monitoring of biochemical parameters in vitro and in vivo have become the goal of many investigations in medical physics. The main imaging technique used is laser-induced luminescence due to its cost effectiveness and diversity of applications [1]. One key parameter in medical investigations, for instance to control photodynamic therapy, is the molecular oxygen concentration. The use of optical methods provides possible means of measuring molecular oxygen. The basis of such a method is the measurement of the luminescence lifetime of a dye which is quenched by molecular oxygen. The molecular oxygen concentration can be monitored two-dimensionally by pixel-wise determination of the luminescence lifetime with a CCD-camera. An oxygen imaging system based on this principle was built and tested with a commercially available oxygen sensitive sol gel-layer. The embedded ruthenium complex is quenched by molecular oxygen and because of the oxygen permeability of the layer; it is suitable for oxygen measurements. The characteristics and dependence on the pH-value and temperature of the luminescence lifetime of the layer were examined in preparation for measurements on tissue to exclude cross-correlation of other quenching processes.

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The examination of functional processes in tissue is gaining importance in medical research. As a result the imaging and monitoring of biochemical parameters in vivo is the goal of many imaging methods. One key parameter in photodynamic therapy (PDT) is the molecular oxygen concentration. Two-dimensional monitoring of oxygen is demanded for PDT but has not yet been achieved. The use of optical methods provides a possible means of measuring molecular oxygen. The basis of this method is the measurement of the luminescence lifetime of a dye that is quenched by molecular oxygen. The molecular oxygen concentration can be monitored two-dimensionally by pixel-wise determination of the luminescence lifetime with a CCD-camera. A new O(2)-imaging system based on this principle is presented in this article. The dye Ru(bpy)(3)(2+) is quenched by molecular oxygen and was used in the first experiments with the system.

Fragestellung: Innerhalb einer Patientenumfrage sollte untersucht werden, inwieweit ein für die Früherkennung des Zervixkarzinoms eingesetztes digitales Kolposkopiesystem, welches neben einer Mitbeobachtungsmöglichkeit per Videomonitor eine digitale Befunddokumentation sowie eine elektronische Arztbriefversendung erlaubt, von den Patientinnen akzeptiert wurde und ob sich Vorteile für die Patientenaufklärung ergaben. Material und Methode: Befragt wurden 100 Patientinnen der Dysplasiesprechstunde der Charité Berlin am Campus Benjamin Franklin (CBF), die dort zur weiteren diagnostischen Abklärung eines auffälligen Zervixbefundes mit dem digitalen Kolposkop untersucht wurden. Die anonyme, schriftliche Befragung erfolgte anhand eines einheitlichen Evaluationsbogens mit 31 Likert-skalierten Items zum Ablauf, der Qualität der Untersuchung sowie zum persönlichen Empfinden. Ergebnisse: 83 Patientinnen beantworteten den Fragebogen, von denen 92% die Untersuchung am Monitor mitverfolgt hatten. 93 % sahen in der Nutzung des Systems eine Verbesserung ihrer ärzt-lichen Betreuung. 86% fühlten sich durch die Mitbeobachtungsmöglichkeit über die einzelnen Untersuchungsschritte besser aufgeklärt. 69% gaben an, dass ihnen die aufgezeichneten kolposkopischen Bilder halfen, gezielt Fragen zur Untersuchung zu stellen. 89 % würden sich wieder mit dem digitalen System untersuchen lassen. 93% fänden es gut, wenn die gespeicherten digitalen Bilder an ihren überweisenden Arzt geschickt würden. 89 % würden es begrüßen, wenn ihr niedergelassener Arzt selbst ein digitales Kolposkopiesystem nutzenwürde. Mehr als die Hälfte (57 %) wäre sogar bereit, die Kosten für eine entsprechende Untersuchung privat zu übernehmen (IGeL). Schlussfolgerung: Die Ergebnisse der durchgeführten Befragung spiegeln eine hohe ZufrieAbstract !Purpose: A patient survey was used to assess patients' acceptance of digital colposcopic systems used for the early detection of cervical cancer, and the advantages of providing better information to patients using improved technical options, i.e. patient observation of video monitors, digital diagnosis documentation, e-letters. Material and Methods: 100 female patients with cervical abnormalities, who were examined with a digital colposcope at the Colposcopic Clinic at the Charité University Hospital Berlin, Campus Benjamin Franklin (CBF), were included in a survey using an anonymous, standard evaluation sheet with 31 Likert scaled items relating to the examination procedure, the quality of the examination and the personal perception of the procedure. Results: A total of 83 patients returned the questionnaire, 92 % of whom had followed the colposcopic examination on the monitor. 93% said the system used was an improvement in medical care. 86% related that having followed the individual examination steps on the monitor, they felt themselves to be better informed. For 69 %, the recorded colposcopic images had helped them formulate relevant questions. 89 % would permit an examination with the digital system again and 93% would welco...