TY - JOUR A1 - Weckesser, Martin A1 - Grießmeier, Martin A1 - Schmidt, Daniela A1 - Sonnenberg, Frank A1 - Ziemons, Karl A1 - Kemna, Lars A1 - Holschbach, Marcus A1 - Langen, Karl-J. A1 - Müller-Gärtner, Hans-W. T1 - Iodine-123 α-methyl tyrosine single-photon emission tomography of cerebral gliomas: standardised evaluation of tumour uptake and extent JF - European Journal of Nuclear Medicine N2 - Single-photon emission tomography (SPET) with the amino acid analogue l-3-[123I]iodo-α-methyl tyrosine (IMT) is helpful in the diagnosis and monitoring of cerebral gliomas. Radiolabelled amino acids seem to reflect tumour infiltration more specifically than conventional methods like magnetic resonance imaging and computed tomography. Automatic tumour delineation based on maximal tumour uptake may cause an overestimation of mean tumour uptake and an underestimation of tumour extension in tumours with circumscribed peaks. The aim of this study was to develop a program for tumour delineation and calculation of mean tumour uptake which takes into account the mean background activity and is thus optimised to the problem of tumour definition in IMT SPET. Using the frequency distribution of pixel intensities of the tomograms a program was developed which automatically detects a reference brain region and draws an isocontour region around the tumour taking into account mean brain radioactivity. Tumour area and tumour/brain ratios were calculated. A three-compartment phantom was simulated to test the program. The program was applied to IMT SPET studies of 20 patients with cerebral gliomas and was compared to the results of manual analysis by three different investigators. Activity ratios and chamber extension of the phantom were correctly calculated by the automatic analysis. A method based on image maxima alone failed to determine chamber extension correctly. Manual region of interest analysis in patient studies resulted in a mean inter-observer standard deviation of 8.7%±6.1% (range 2.7%–25.0%). The mean value of the results of the manual analysis showed a significant correlation to the results of the automatic analysis (r = 0.91, P<0.0001 for the uptake ratio; r = 0.87, P<0.0001 for the tumour area). We conclude that the algorithm proposed simplifies the calculation of uptake ratios and may be used for observer-independent evaluation of IMT SPET studies. Three-dimensional tumour recognition and transfer to co-registered morphological images based on this program may be useful for the planning of surgical and radiation treatment. Y1 - 1998 SN - 1619-7089 VL - 25 IS - 2 SP - 150 EP - 156 ER - TY - JOUR A1 - Hoffmann, C. P. A1 - Lindemann, Markus A1 - Zimmermann, Hans-Dieter T1 - Logistik-Ressourcen im World Wide Web JF - Wirtschaftsinformatik. Vol. 40 (1998), iss. 3 Y1 - 1998 SN - 0937-6429 SP - 245 EP - 250 ER - TY - JOUR A1 - Förster, Arnold A1 - Hauke, M. A1 - Jakumeit, J. A1 - Krafft, B. T1 - DX Centers in Al0.3Ga0.7As/GaAs Analyzed by Point Contact Measurements. Hauke, M.; Jakumeit, J.; Krafft, B.; Nimtz, G.; Förster, A.; Lüth, H. JF - Journal of Applied Physics. 84 (1998), H. 4 Y1 - 1998 SN - 1089-7550 SP - 2034 EP - 2039 ER - TY - JOUR A1 - Förster, Arnold A1 - Griebel, M. A1 - Indlekofer, K. M. A1 - Lüth, H. T1 - Transport properties of gated resonant tunneling diodes in the single electron regime. Griebel, M.; Indlekofer, K. M.; Förster, A.; Lüth, H. JF - Journal of Applied Physics. 84 (1998), H. 12 Y1 - 1998 SN - 1089-7550 SP - 6719 EP - 6724 ER - TY - JOUR A1 - Förster, Arnold A1 - Lachenmann, S. G. A1 - Kastalsky, A. A1 - Uhlisch, D. T1 - Hybrid superconductor/semiconductor step junction with three terminals. Lachenmann, S. G.; Kastalsky, A.; Förster A.; Uhlisch, D.; Neurohr, K.; Schäpers, Th. JF - Journal of Applied Physics. 83 (1998), H. 12 Y1 - 1998 SN - 1089-7550 SP - 8077 EP - 8079 ER - TY - JOUR A1 - Förster, Arnold A1 - Darmo, J. A1 - Dubecky, F. A1 - Kordos, P. T1 - Annealing effect on concentration of EL6-like deep-level state in low-temperature-grown molecular beam epitaxial GaAs. Darmo, J.; Dubecky, F.; Kordos, P.; Förster, A. JF - Applied Physics Letters. 72 (1998), H. 5 Y1 - 1998 SN - 1077-3118 SP - 590 EP - 592 ER - TY - JOUR A1 - Scholl, Ingrid A1 - Palm, Christoph A1 - Lehmann, Thomas A1 - Spitzer, Klaus T1 - Nutzung eines Farbkonstanz-Algorithmus zur Entfernung von Glanzlichtern in laryngoskopischen Bildern. Palm, Christoph; Scholl, Ingrid, Lehmann, Thomas; Spitzer, Klaus. JF - Methoden der Medizinischen Informatik, Biometrie und Epidemiologie in der modernen Informationsgesellschaft Y1 - 1998 SN - 3-8208-1335-7 N1 - Jahrestagung der GMDS ; 43 SP - 300 EP - 303 PB - MVV, Medien und Medizin CY - München ER - TY - JOUR A1 - Scholl, Ingrid A1 - Palm, Christoph A1 - Lehmann, Thomas A1 - Spitzer, Klaus T1 - Quantitative Farbmessung in laryngoskopischen Bildern. Palm, C; Scholl, I; Lehmann, TM; Spitzer, K. JF - Bildverarbeitung für die Medizin 1998. Hrsg.: Thomas Lehmann ... Y1 - 1998 SN - 3-540-63885-7 SP - 412 EP - 416 PB - Springer CY - Berlin ER - TY - JOUR A1 - Mertens, Josef T1 - Required technologies for supersonic aircraft JF - Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamic research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998 Y1 - 1998 SN - 92-837-1007-X N1 - (RTO educational notes ; 4) SP - 5.1 EP - 5.16 PB - Research and Technology Organization CY - Neuilly-sur-Seine ER - TY - JOUR A1 - Mertens, Josef T1 - Multi point design challenges for supersonic transports JF - Fluid dynamics research on supersonic aircraft : this report is a compilation of the edited proceedings of the special course on "Fluid dynamics research on supersonic aircraft" held at the Karman Institute for Fluid Dynamics (VKI) in Rhode-Saint-Genese, Belgium, 25-29 May 1998 Y1 - 1998 SN - 92-837-1007-X SP - 8.1 EP - 8.12 PB - Research and Technology Organization CY - Neuilly-sur-Seine ER -