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Author

  • Karl Ziemons (66)
  • M. Streun (21)
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  • Hans Herzog (4)
  • Hans-W. Müller-Gärtner (4)
  • K. Zwoll (4)
  • Karl-J. Langen (4)
  • H. Herzog (3)
  • Mattea Müller-Veggian (3)
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  • Article (63)
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  • English (59)
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Keywords

  • Heterostructure (1)
  • Image Reconstruction (1)
  • Metascintillator (1)
  • Multiple TOF kernels (1)
  • TOF PET (1)

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SPECT with HMPAO compared to PET with FDG in Huntington disease (1994)
Henning Boecker ; Torsten Kuwert ; Karl-J. Langen ; Herwig W. Lange ; Norbert Czech ; Karl Ziemons ; Hans Herzog ; Shekar Shikare ; Anton Weindl ; Ludwig E. Feinendegen
3-[123I]iodo-α-methyltyrosine and [methyl-11C]-L-methionine uptake in cerebral gliomas: a compara-tive study using SPECT and PET (1997)
Karl J. Langen ; Karl Ziemons ; Jürgen C. W. Kiwit ; Hans Herzog ; Torsten Kuwert ; Wolfgang Bock ; Gerhard Stöcklin ; Ludwig E. Feinendegen ; Hans-W. Müller-Gärtner
Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy (1997)
Matthias Weckesser ; Andreas Hufnagel ; Karl Ziemons ; Martin Grießmeier ; Frank Sonnenberg ; Thomas Hackländer ; Karl-J. Langen ; Markus Holschbach ; Christian E. Elger ; Hans-W. Müller-Gärtner
Animal experiments and preliminary results in humans have indicated alterations of hippocampal muscarinic acetylcholine receptors (mAChR) in temporal lobe epilepsy. Patients with temporal lobe epilepsy often present with a reduction in hippocampal volume. The aim of this study was to investigate the influence of hippocampal atrophy on the quantification of mAChR with single photon emission tomography (SPET) in patients with temporal lobe epilepsy. Cerebral uptake of the muscarinic cholinergic antagonist [123I]4-iododexetimide (IDex) was investigated by SPET in patients suffering from temporal lobe epilepsy of unilateral (n=6) or predominantly unilateral (n=1) onset. Regions of interest were drawn on co-registered magnetic resonance images. Hippocampal volume was determined in these regions and was used to correct the SPET results for partial volume effects. A ratio of hippocampal IDex binding on the affected side to that on the unaffected side was used to detect changes in muscarinic cholinergic receptor density. Before partial volume correction a decrease in hippocampal IDex binding on the focus side was found in each patient. After partial volume no convincing differences remained. Our results indicate that the reduction in hippocampal IDex binding in patients with epilepsy is due to a decrease in hippocampal volume rather than to a decrease in receptor concentration.
Whole-body kinetics and dosimetry of L-3[123I]-iodo-α-methyltyrosine (1997)
Daniela Schmidt ; Karl-J. Langen ; Hans Herzog ; Jochen Wirths ; Markus Holschbach ; Jürgen C. W. Kiwit ; Karl Ziemons ; Heinz-H. Coenen ; Hans-W. Müller-Gärtner
Iodine-123 α-methyl tyrosine single-photon emission tomography of cerebral gliomas: standardised evaluation of tumour uptake and extent (1998)
Martin Weckesser ; Martin Grießmeier ; Daniela Schmidt ; Frank Sonnenberg ; Karl Ziemons ; Lars Kemna ; Marcus Holschbach ; Karl-J. Langen ; Hans-W. Müller-Gärtner
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.
Vorrichtung zum Halten eines lebenden Objektes bei physiologischen Messungen (2005)
Richard Achten ; Andreas Bauer ; Walter Bertram ; Markus Cremer ; Jos Daemen ; Markus Dehnhardt ; Manfred Fleischer ; Peter Kirchner ; Marco Leyendecker ; Uwe Pietrzyk ; Jakob Schmitz ; Karl Ziemons ; Karl Zilles
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.
Continuous head motion detection during MEG measurement using head location coils (2001)
H. Peters ; Karl Ziemons ; J. Dammers ; Mattea Müller-Veggian
Treating the Gain Non-Uniformity of Multi Channel PMTs by Channel-Specific Trigger Levels (2006)
M. Streun ; U. Chavan ; H. Lame ; C. Parl ; Mattea Müller-Veggian ; Karl Ziemons
The ClearPET neuro scanner: a dedicated LSO/LuYAP phoswich small animal PET scanner (2004)
Karl Ziemons ; R. Achten ; E. Auffray ; Mattea Müller-Veggian
Iterative image reconstruction with weighted pixel contribution to projection element (1990)
Karl Ziemons ; H. Herzog ; L. E. Feinendegen
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