TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - 2002 IEEE Nuclear Science Symposium Conference Record, Vol. 3
N2  - Within the Crystal Clear Collaboration four centres are developing 2nd generation high performance small animal PET scanners for different kinds of animals and medical applications. The first prototypes are PMT-based systems including depth of interaction (DOI) detection by using a phoswich layer of LSO and LuYAP. The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in FOVs caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN) was used. The simulations have shown that all PMT designs with one-to-one coupling of crystals have a very nonlinear axial sensitivity profile. By shifting every other PMT 1/4 of a PMT length in axial direction the sampling of the FOVs became more homogeneous. At an energy threshold of 350keV the regression coefficient increases from 0.818 for the non-shifted to 0.993 for the shifted design. Simulations of a point source centred in the FOV (threshold: 350keV) resulted in sensitivities of 4.2% for a 4×20PMT (LSO/LuYAP a 10mm) and 3.8% for a 4×16PMT (LSO/LuYAP a 8mm) ring design. The 3D-MLEM reconstruction of a point source shows the enormous improvement of resolution using a crystal double layer with DOI (3.1mm at 40mm from CFOV) instead of a 20mm single layer (11.9mm).
Y1  - 2003
SN  - 1082-3654
SP  - 682
EP  - 686
ER  - 
TY  - JOUR
A1  - Heinrichs, U.
A1  - Pietrzyk, U.
A1  - Ziemons, Karl
T1  - Design optimization of the PMT-ClearPET prototypes based on simulation studies with GEANT3
JF  - IEEE Transactions on Nuclear Science
N2  - Within the Crystal Clear Collaboration (CCC), four centers are developing second generation high performance small animal positron emission tomography (PET) scanners for different kinds of animals and medical applications. The first prototypes are photomultiplier tube (PMT)-based systems including depth of interaction (DOI) detection by using a phoswich layer of lutetium oxyorthosilicate (LSO) and lutetium yttrium aluminum perovskite (LuYAP). The aim of these simulation studies is to optimize sensitivity and spatial resolution of given designs, which vary in fields of view (FOVs) caused by different detector configurations (ring/octagon) and sizes. For this purpose the simulation tool GEANT3 (CERN, Geneva, Switzerland) was used.
Y1  - 2003
SN  - 0018-9499
VL  - 50
IS  - 5
SP  - 1428
EP  - 1432
ER  - 
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  - Hautzel, H.
A1  - Taylor, J. G.
A1  - Krause, B. J.
A1  - Schmitz, N.
A1  - Tellmann, L.
A1  - Ziemons, Karl
A1  - Shah, N. J.
A1  - Herzog, H.
A1  - Müller-Gärtner, H.-W.
T1  - The motion aftereffect: more than area V5/MT? Evidence from 15O-butanol PET studies
JF  - Brain Research
N2  - The motion aftereffect is a perceptual phenomenon which has been extensively investigated both psychologically and physiologically. Neuroimaging techniques have recently demonstrated that area V5/MT is activated during the perception of this illusion. The aim of this study was to test the hypothesis if a more broadly distributed network of brain regions subserves the motion aftereffect. To identify the neuronal structures involved in the perception of the motion aftereffect, regional cerebral blood flow (rCBF) measurements with positron emission tomography were performed in six normal volunteers. Data were analysed using SPM96. The motion-sensitive visual areas including area V5/MT were activated in both hemispheres. Additionally, the lateral parietal cortex bilaterally, the right dorsolateral prefrontal cortex, the anterior cingulate cortex and the left cerebellum showed significant increases in rCBF values during the experience of the waterfall illusion. In a further reference condition with identical attentional demand but no perception of a motion aftereffect elevated rCBF were found in these regions as well. In conclusion, our findings support the notion that the perceptual illusion of motion arises exclusively in the motion-sensitive visual area V5/MT. In addition, a more widespread network of brain regions including the prefrontal and parietal cortex is activated during the waterfall illusion which represents a non-motion aftereffect-specific subset of brain areas but is involved in more basic attentional processing and cognition.
Y1  - 2001
SN  - 0006-8993
VL  - 892
IS  - 2
SP  - 281
EP  - 292
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  - 
TY  - JOUR
A1  - Beer, S.
A1  - Streun, M.
A1  - Hombach, T.
A1  - Buehler, J.
A1  - Jahnke, S.
A1  - Khodaverdi, M.
A1  - Larue, H.
A1  - Minwuyelet, S.
A1  - Parl, C.
A1  - Roeb, G.
A1  - Schurr, U.
A1  - Ziemons, Karl
T1  - Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants
JF  - Physics in Medicine and Biology
N2  - Positron emitters such as 11C, 13N and 18F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is 11CO2 since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, front-end electronics and data acquisition architecture of the scanner are based on the ClearPET™ system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements.
Y1  - 2010
U6  - http://dx.doi.org/10.1088/0031-9155/55/3/006
SN  - 1361-6560
VL  - 55
IS  - 3
SP  - 635
EP  - 646
PB  - IOP
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Auffray, E.
A1  - Bruyndonckx, P.
A1  - Devroede, O.
A1  - Fedorov, A.
A1  - Ziemons, Karl
T1  - The ClearPET project
JF  - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
N2  - The Crystal Clear Collaboration has designed and is building a high-resolution small animal PET scanner. The design is based on the use of the Hamamatsu R7600-M64 multi-anode photomultiplier tube and a LSO/LuYAP phoswich matrix with one to one coupling between the crystals and the photo-detector. The complete system will have 80 PM tubes in four rings with an inner diameter of 137 mm and an axial field of view of 110 mm. The PM pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the pulse arrival time. Single gamma interactions are recorded and coincidences are found by software. The gantry allows rotation of the detector modules around the field of view. Simulations, and measurements a 2×4 module test set-up predict a spatial resolution of 1.5 mm in the centre of the field of view and a sensitivity of 5.9% for a point source in the centre of the field of view.
Y1  - 2004
SN  - 0168-9002
N1  - Proceedings of the 2nd International Conference on Imaging Technologies in Biomedical Sciences
VL  - 527
IS  - 1-2
SP  - 171
EP  - 174
ER  - 
TY  - GEN
A1  - Achten, Richard
A1  - Bauer, Andreas
A1  - Bertram, Walter
A1  - Cremer, Markus
A1  - Daemen, Jos
A1  - Dehnhardt, Markus
A1  - Fleischer, Manfred
A1  - Kirchner, Peter
A1  - Leyendecker, Marco
A1  - Pietrzyk, Uwe
A1  - Schmitz, Jakob
A1  - Ziemons, Karl
A1  - Zilles, Karl
T1  - Vorrichtung zum Halten eines lebenden Objektes bei physiologischen Messungen
N2  - Die vorliegende Erfindung betrifft eine Vorrichtung zum Halten eines lebenden Objektes bei physiologischen Messungen mit einem Basiselement und Mitteln zum Arretieren des lebenden Objektes, die atraumatische Ohrenhalter sowie ein Mundstück aufweisen, das mit einer Aussparung für die Zähne des Lebewesens versehen ist, mit einem Masseanteil von wenigstens 95% an glasfaserverstärktem Kunststoff.
Y1  - 2005
N1  - Patent Anmelder : Forschungszentrum Jülich GmbH
SP  - 1
EP  - 17
ER  -