TY - JOUR A1 - Heinrich, U. A1 - Blum, A. A1 - Bussmann, N. A1 - Engels, R. A1 - Kemmerling, G. A1 - Weber, S. A1 - Ziemons, Karl T1 - Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment N2 - The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw, mechanically polished and etched LSO crystals (size 2×2×10 mm3) were combined with various reflector materials (Teflon tape, Teflon matrix, BaSO4) and exposed to a 22Na source. In order to ensure the statistical reliability of the results, groups of 10 LSO crystals each were measured for all combinations of surface treatment and reflector material. Using no reflector material the light output increased up to 551±35% by mechanical polishing the surface compared to 100±5% for raw crystals. Etching the surface increased the light output to 441±29%. The untreated crystals had an energy resolution of 24.6±4.0%. By mechanical polishing the surface it was possible to achieve an energy resolution of 13.2±0.8%, by etching of 14.8±0.7%. In combination with BaSO4 as reflector material the maximum increase of light output has been established to 932±57% for mechanically polished and 895±61% for etched crystals. The combination with BaSO4 also caused the best improvement of the energy resolution up to 11.6±0.2% for mechanically polished and 12.2±0.3% for etched crystals. Relating to the light output there was no significant statistical difference between the two surface treatments in combination with BaSO4. In contrast to this, the statistical results of the energy resolution have shown the combination of mechanical polishing and BaSO4 as the optimum. Y1 - 2002 SN - 0168-9002 N1 - Proceedings of the 6th International Conference on Inorganic Scin tillators and their Use in Scientific and Industrial Applications VL - 486 IS - 1-2 SP - 60 EP - 66 ER - TY - JOUR A1 - Grießmeier, M. A1 - Sonnenberg, F. A1 - Weckesser, M. A1 - Ziemons, Karl A1 - Langen, K.-J. A1 - Müller-Gärtner, H. W. T1 - Improvement of SPECT quantification in small brain structures by using experiment based recovery-coefficient corrections JF - European Journal of Nuclear Medicine Y1 - 1996 SN - 1619-7089 N1 - Abstracts ; PSu827 VL - 23 IS - 9 SP - 1238 EP - 1238 ER - TY - JOUR A1 - Garibaldi, F. A1 - Beging, Stefan A1 - Canese, R. A1 - Carpinelli, G. A1 - Clinthorne, N. A1 - Colilli, S. A1 - Cosentino, L. A1 - Finocchiaro, P. A1 - Giuliani, F. A1 - Gricia, M. A1 - Lucentini, M. A1 - Majewski, S. A1 - Monno, E. A1 - Musico, P. A1 - Santavenere, F. A1 - Tödter, J. A1 - Wegener, Hans-Peter A1 - Ziemons, Karl T1 - A novel TOF-PET MRI detector for diagnosis and follow up of the prostate cancer JF - European Physical Journal Plus Y1 - 2017 U6 - http://dx.doi.org/10.1140/epjp/i2017-11662-x SN - 2190-5444 VL - 132 IS - 9 PB - Springer CY - Berlin ER - TY - JOUR A1 - Fink, G. R. A1 - Marshall, J. C. A1 - Shah, N. J. A1 - Weiss, P.H. A1 - Halligan, P. W. A1 - Grosse-Ruyken, M. A1 - Ziemons, Karl A1 - Zilles, K. A1 - Freund, H. J. T1 - Line bisection judgments implicate right parietal cortex and cerebellum as assessed by fMRI JF - Neurology Y1 - 2000 SN - 1526-632X VL - 54 IS - 6 SP - 1324 EP - 1331 ER - TY - JOUR A1 - Erki, I. A1 - Kleines, H. A1 - Ziemons, Karl A1 - Zwoll, K. ED - Lehmann, Thomas T1 - Interaktives System zur Darstellung funktionaler Bilddaten JF - Bildverarbeitung für die Medizin : Algorithmen - Systeme - Anwendungen Y1 - 1997 SN - 3-86073-519-5 N1 - Proceedings des Aachener Workshops am 8. u. 9. November 1996 ; PP_002 Posterpräsentation SP - 249 EP - 254 PB - Verl. der. Augustinus-Buchh. CY - Aachen ER - TY - JOUR A1 - Christ, D. A1 - Hollendung, A. A1 - Larue, H. A1 - Parl, C. A1 - Streun, M. A1 - Weber, S. A1 - Ziemons, Karl A1 - Halling, H. T1 - Homogenization of the MultiChannel PM gain by inserting light attenuating masks JF - 2003 IEEE Nuclear Science Symposium Conference Record, Vol. 4 N2 - MultiChannel Photomultipliers (PM), like the R7600-00-M64 or R5900-00-M64 from Hamamatsu, are often chosen as photodetectors in high-resolution positron emission tomography (PET). A major problem of this PM is the nonuniform channel gain. In order to solve this problem, light attenuating masks were created. The aim of the masks is a homogenization of the output of all 64 channels using different hole sizes at the channel positions. The hole area, which is individually defined for the different channels, is inversely proportional to the channel gain. The measurements by inserting light attenuating masks improved a homogenization to a ratio of 1:1.2. Y1 - 2004 SN - 1082-3654 SP - 2382 EP - 2385 ER - TY - JOUR A1 - Choi, Chang-Hoon A1 - Felder, Tim A1 - Felder, Jörg A1 - Tellmann, Lutz A1 - Hong, Suk-Min A1 - Wegener, Hans-Peter A1 - Shah, N Jon A1 - Ziemons, Karl T1 - Design, evaluation and comparison of endorectal coils for hybrid MR-PET imaging of the prostate JF - Physics in Medicine & Biology N2 - Prostate cancer is one of the most common cancers among men and its early detection is critical for its successful treatment. The use of multimodal imaging, such as MR-PET, is most advantageous as it is able to provide detailed information about the prostate. However, as the human prostate is flexible and can move into different positions under external conditions, it is important to localise the focused region-of-interest using both MRI and PET under identical circumstances. In this work, we designed five commonly used linear and quadrature radiofrequency surface coils suitable for hybrid MR-PET use in endorectal applications. Due to the endorectal design and the shielded PET insert, the outer face of the coils investigated was curved and the region to be imaged was outside the volume of the coil. The tilting angles of the coils were varied with respect to the main magnetic field direction. This was done to approximate the various positions from which the prostate could be imaged. The transmit efficiencies and safety excitation efficiencies from simulations, together with the signal-to-noise ratios from the MR images were calculated and analysed. Overall, it was found that the overlapped loops driven in quadrature were superior to the other types of coils we tested. In order to determine the effect of the different coil designs on PET, transmission scans were carried out, and it was observed that the differences between attenuation maps with and without the coils were negligible. The findings of this work can provide useful guidance for the integration of such coil designs into MR-PET hybrid systems in the future. Y1 - 2020 U6 - http://dx.doi.org/10.1088/1361-6560/ab87f8 SN - 0031-9155 VL - 65 IS - 11 PB - IOP CY - Bristol ER - TY - JOUR A1 - Bussmann, N. A1 - Engels, R. A1 - Fuss, L. A1 - Kemmerling, G. A1 - Reinartz, R. A1 - Langen, K.-J. A1 - Schelten, J. A1 - Ziemons, Karl T1 - Performance measurement of a new high resolution detector system for I-131 thyroid studies JF - 2000 IEEE Nuclear Science Symposium Conference Record, Vol. 3 N2 - A 2-dimensional detector system for high resolution thyroid I-131 scintigraphy was developed. It has a sensitive area of 4 cm×4 cm and consists of a lead-collimator and an array of 10×10 EGO crystals combined with a position sensitive photomultiplier. The spatial resolution and the sensitivity of the detector has been measured and compared to two commercially available gamma-cameras. Furthermore first patient measurements have been carried out Y1 - 2000 SN - 1082-3654 SP - 22/35 EP - 22/37 ER - TY - JOUR A1 - Boecker, Henning A1 - Kuwert, Torsten A1 - Langen, Karl-J. A1 - Lange, Herwig W. A1 - Czech, Norbert A1 - Ziemons, Karl A1 - Herzog, Hans A1 - Shikare, Shekar A1 - Weindl, Anton A1 - Feinendegen, Ludwig E. T1 - SPECT with HMPAO compared to PET with FDG in Huntington disease JF - Journal of Computer Assisted Tomography Y1 - 1994 SN - 1532-3145 VL - 18 IS - 4 SP - 542 EP - 548 ER - TY - JOUR A1 - Berghoff, G. A1 - Lanske, D. A1 - Schultze, K. A1 - Ziemons, Karl T1 - Jets and QCD-effects in muon-nuclean scattering JF - Verhandlungen der Deutschen Physikalischen Gesellschaft Y1 - 1988 SN - 0420-0195 VL - 23 IS - 5 ER -