"The art of making beautiful prints in less than an hour : die Dunkelkammer in filmischer Reflexion

Mit erstaunlicher Persistenz findet die Dunkelkammer über Jahrzehnte hinweg Eingang in den fiktionalen Film: als visueller wie narrativer Topos, als Handlungsort und als stabiles ikonisches Ensemble - und dies durchaus unter Absehung von der tatsächlichen historischen Relevanz der Dunkelkammer für die fotografischen Fertigungsprozesse im jeweiligen Handlungszeitraum der Filme. Mehr noch: Insofern selbst heute noch Filme mit klarem Gegenwartsbezug die Dunkelkammer thematisieren und reflektieren, findet sich auch hierin die Gleichzeitigkeit des Ungleichzeitigen wieder. Selbst in Filmen, die ganz selbstverständlich dem Primat der Digitalfotografie und ihrer Materialisierung auf den verschiedensten Displays huldigen, bleiben die Dunkelkammer und die in ihr vollzogenen Prozesse präsent. Im Folgenden soll daher den prominentesten filmischen Narrativen und Motivgestaltungen dieses Zusammenhangs sowie der Frage nach Gründen für die offenkundige Faszination des Mediums Film gerade für diesen Teil der fotografischen Bildgenese nachgegangen werden. Es wird sich zeigen, dass ungeachtet der relativen Breite an einschlägigen Motivverwendungen doch rekurrierende narrative und ikonische Muster identifiziert werden können, die der Dunkelkammer als Handlungsort einen begrenzten Korpus von Funktionalisierungen und Handlungsketten zuweisen und sie dabei als je unterschiedlichen semantischen Raum konstruieren. Gemäß der medienkomparatistischen Grundannahme, dass die Fremdreflexion eines Mediums immer auch eine Selbstreflexion des eigenen Mediums mit sich bringt, wird ferner zu beobachten sein, welche Figurationen von Fremd- und Selbstbeobachtung der Film in seiner Handhabung des Dunkelkammermotivs vollzieht

Automatic Tumor Segmentation With a Convolutional Neural Network in Multiparametric MRI: Influence of Distortion Correction

Precise tumor segmentation is a crucial task in radiation therapy planning. Convolutional neural networks (CNNs) are among the highest scoring automatic approaches for tumor segmentation. We investigate the difference in segmentation performance of geometrically distorted and corrected diffusion-weighted data using data of patients with head and neck tumors; 18 patients with head and neck tumors underwent multiparametric magnetic resonance imaging, including T2w, T1w, T2*, perfusion (ktrans), and apparent diffusion coefficient (ADC) measurements. Owing to strong geometrical distortions in diffusion-weighted echo planar imaging in the head and neck region, ADC data were additionally distortion corrected. To investigate the influence of geometrical correction, first 14 CNNs were trained on data with geometrically corrected ADC and another 14 CNNs were trained using data without the correction on different samples of 13 patients for training and 4 patients for validation each. The different sets were each trained from scratch using randomly initialized weights, but the training data distributions were pairwise equal for corrected and uncorrected data. Segmentation performance was evaluated on the remaining 1 test-patient for each of the 14 sets. The CNN segmentation performance scored an average Dice coefficient of 0.40 ± 0.18 for data including distortion-corrected ADC and 0.37 ± 0.21 for uncorrected data. Paired t test revealed that the performance was not significantly different (P = .313). Thus, geometrical distortion on diffusion-weighted imaging data in patients with head and neck tumor does not significantly impair CNN segmentation performance in use

Serial [18F]-fluoromisonidazole PET during radiochemotherapy for locally advanced head and neck cancer and its correlation with outcome.

PURPOSE The aim was to assess changes of tumour hypoxia during primary radiochemotherapy (RCT) for head and neck cancer (HNC) and to evaluate their relationship with treatment outcome. MATERIAL AND METHODS Hypoxia was assessed by FMISO-PET in weeks 0, 2 and 5 of RCT. The tumour volume (TV) was determined using FDG-PET/MRI/CT co-registered images. The level of hypoxia was quantified on FMISO-PET as TBRmax (SUVmaxTV/SUVmean background). The hypoxic subvolume (HSV) was defined as TV that showed FMISO uptake ⩾1.4 times blood pool activity. RESULTS Sixteen consecutive patients (T3-4, N+, M0) were included (mean follow-up 31, median 44months). Mean TBRmax decreased significantly (p<0.05) from 1.94 to 1.57 (week 2) and 1.27 (week 5). Mean HSV in week 2 and week 5 (HSV2=5.8ml, HSV3=0.3ml) were significantly (p<0.05) smaller than at baseline (HSV1=15.8ml). Kaplan-Meier plots of local recurrence free survival stratified at the median TBRmax showed superior local control for less hypoxic tumours, the difference being significant at baseline and after 2weeks (p=0.031, p=0.016). CONCLUSIONS FMISO-PET documented that in most HNC reoxygenation starts early during RCT and is correlated with better outcome

Analysis of relation between hypoxia PET imaging and tissue-based biomarkers during head and neck radiochemotherapy.

BACKGROUND Tumor hypoxia is associated with poor prognosis and outcome and can be visualized using 18F-MISO-positron emission tomography (PET) imaging. The goal of this study was to evaluate the correlation between biological markers and biological imaging in a group of patients in whom a correlation between biological imaging and outcome has previously been demonstrated. MATERIAL AND METHODS In a prospective pilot project, 16 patients with locally advanced cancer of the head and neck underwent 18F-MISO-PET scans before and during primary radiochemotherapy in addition to 18F-FDG-PET and computed tomography (CT). Tumor biopsies were stained for three tissue-based markers (Ku80, CAIX, CD44); in addition, human papillomavirus (HPV) status was assessed. H-scores of marker expression were generated and the results were correlated with the biological imaging and clinical outcome. RESULTS No statistically significant correlation was established between the H-scores for Ku80, CD44 and CAIX or between any of the H-scores and the imaging variables (tumor volume on 18F-FDG-PET in ml, hypoxic subvolume as assessed by 18F-MISO-PET in ml, and SUVmax tumor/SUVmean muscle during the 18F-MISO-PET). A statistically significant negative correlation was found between CD44 H-score and HPV status (p = .004). Cox regression analysis for overall survival and recurrence-free survival showed one significant result for CAIX being associated with improved overall survival [hazard ratio 0.96 (0.93-1.00), p = .047]. CONCLUSION Expression of Ku80, CAIX and CD44 as assessed by immunohistochemistry of tumor biopsies were not correlated to one another or the biological imaging data. However, there was a significant influence of CAIX on overall survival and between CD44 and HPV