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  • 1995-1999  (3)
  • 1975-1979
  • 1950-1954
  • 1998  (3)
  • Chemistry  (1)
  • Mundhöhlenkarzinom
  • thermodynamic properties
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mund-, Kiefer- und Gesichtschirurgie 2 (1998), S. 181-187 
    ISSN: 1434-3940
    Keywords: Schlüsselwörter Positronen Emmissions-Tomographie ; Mundhöhlenkarzinom ; Neck-Dissektion ; Metastasen ; Standardisierte Uptake Values ; Key words PET ; Oral cancer ; Squamous cell carcinoma ; Neck dissection ; Head and neck metastases ; Radionuclide studies ; Standardized uptake values
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Objective: The lack of sensitivity and specificity of conventional imaging techniques based on morphological critera is responsible for considerable limitations in the staging and surveillance of oral cancer. Therefore, this study investigates the contribution of [F18]-2-fluordesoxyglucose (FDG) positron emission tomography (PET) to tumor management with special regard to lymph-node involvement and therapeutic monitoring after radiotherapy. Design: Prospective observational study. Patients: Twenty-one patients with advanced oral cancer, predominantly T3/T4. Intervention: FDG-PET scans before and after preoperative radio(chemo)therapy. Standardized uptake values (SUV) were determined for the tumor site and lymph-node areas. PET scans were correlated to histological findings after ablative tumor surgery. Results: FDG-PET yielded superior sensitivity and specificity for tumor and lymph-node assessment. The effect of radiotherapy was reflected by the metabolic activity of the tumor, which shows a close correlation between the decrease of FDG uptake and histologic tumor regression. PET detected distant metastases and simultaneous tumors. Conclusion: FDG-PET is a challenging imaging technique with the potential to improve staging procedures for oral cancer. In the monitoring of metabolic activity of the tumor in the course of radio(chemo)therapy, FDG-PET allows objective measurement of the treatment response.
    Notes: Fragestellung: Die Sensitivität und Spezifität konventioneller, an morphologischen Parametern orientierter, objektiver, bildgebender Verfahren zur prätherapeutischen Einschätzung des Lymphknotenstatus und Therapiekontrolle von Mundhöhlenkarzinomen sind für das prätherapeutische Staging und Therapieentscheidungen nicht immer zuverlässig. Es wird daher untersucht, ob die über FDG-PET gewonnenen Daten des Tumormetabolismus zur Präzisierung des Stagings beitragen können. Patienten und Methode: 21 Patienten mit Mundhöhlenkarzinomen, vorwiegend der Stadien T3/T4, wurden in eine prospektive Beobachtungsstudie einbezogen. FDG-PET-Untersuchungen erfolgten in der Regel vor und nach präoperativer Radio(chemo)therapie mit 36(50) Gy und Cisplatin. Der Tumormetabolismus wurde semiquantitativ über standardisierte Uptake values (SUV) bewertet. Die PET-Befunde wurden mit dem histologischem Befund und (bei M-Befunden) mit dem Verlauf korreliert. Ergebnisse: Sämtliche Primärtumorlokalisationen wurden durch die PET erfaßt. Die PET erreichte eine sehr hohe Sensitivität (92%) und Spezifität (92%) für den Nachweis von Lymphknotenfiliae. Nach Radio(chemo)therapie zeigte sich eine weitgehende Übereinstimmung zwischen der Rückbildung des Tumormetabolismus und dem histologisch verifizierten Ausmaß der Tumorregression. Die PET-Untersuchung detektierte differentialtherapeutisch relevante M- und Zweitbefunde. Schlußfolgerung: Ergänzend zu etablierten, morphologisch bildgebenden Verfahren kann die PET die präoperative Einschätzung, insbesondere des Lymphknoten- und M-Status, präzisieren und erscheint daher hilfreich in der Individualisierung onkologischer Therapiekonzepte bei ausgedehnten Mundhöhlenkarzinomen. Durch die semiquantitative Bewertung des Tumormetabolismus wird ein individuelles Monitoring der Strahlentherapie, aber auch anderer Therapiemodalitäten grundsätzlich möglich.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of thermophysics 19 (1998), S. 1121-1132 
    ISSN: 1572-9567
    Keywords: caloric properties ; density ; equation of state ; nitrogen ; thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new formulation describing the thermodynamic properties of nitrogen has been developed. New data sets which have been used to improve the representation of the p–ρ–T surface of gaseous, liquid and supercritical nitrogen, including the saturated states are now available. New measurements on the speed of sound from spherical resonators have been used to improve the accuracy of caloric properties in gaseous and supercritical nitrogen. State-of-the-art algorithms for the optimization of the mathematical structure of the equation and special functional forms for an improved description of the critical region were used to represent even the most accurate data within their experimental uncertainty. The uncertainty in density of the new reference equation of state ranges from ±0.01% between 270 and 350 K at pressures less than 12MPa, within ±0.02% over all other temperatures less than 550 K and pressures less than 12 MPa, and up to a maximum of ±0.6% at the highest pressures. The equation is valid from the triple point to temperatures of 1000 K and pressures up to 2200 MPa. The new formulation yields a reasonable extrapolation up to the limits of chemical stability of nitrogen as indicated by comparison to experimental shock tube data. Constraints regarding the structure of the equation ensure reasonable extrapolated properties up to temperatures and pressures of 5000 K and 25 GPa. For typical calibration applications, the new reference equation is supplemented by a simple but also highly accurate formulation, valid only for supercritical nitrogen between 270 and 350 K at pressures up to 30 MPa.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 70 (1998), S. 1198-1199 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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