TY  - JOUR
A1  - Langen, Karl J.
A1  - Ziemons, Karl
A1  - Kiwit, Jürgen C. W.
A1  - Herzog, Hans
A1  - Kuwert, Torsten
A1  - Bock, Wolfgang
A1  - Stöcklin, Gerhard
A1  - Feinendegen, Ludwig E.
A1  - Müller-Gärtner, Hans-W.
T1  - 3-[123I]iodo-α-methyltyrosine and [methyl-11C]-L-methionine uptake in cerebral gliomas: a compara-tive study using SPECT and PET
JF  - Journal of Nuclear Medicine
Y1  - 1997
SN  - 0161-5505
VL  - 38
IS  - 4
SP  - 517
EP  - 522
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Larue, H.
A1  - Parl, C.
A1  - Ziemons, Karl
T1  - A compact PET detector readout using charge-to-time conversion
JF  - 2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)
N2  - The readout of gamma detectors is considerably simplified when the event intensity is encoded as a pulse width (Pulse Width Modulation, PWM). Time-to-Digital-Converters (TDC) replace the conventional ADCs and multiple TDCs can be realized easily in one PLD chip (Programmable Logic Device). The output of a PWM stage is only one digital signal per channel which is well suited for transport so that further processing can be performed apart from the detector. This is particularly interesting for large systems with high channel density (e.g. high resolution scanners). In this work we present a circuit with a linear transfer function that requires a minimum of components by performing the PWM already in the preamp stage. This allows a very compact and also cost-efficient implementation of the front-end electronics.
Y1  - 2009
SN  - 1082-3654
SP  - 1868
EP  - 1870
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - A measurement of the ratio of the nucleon structure function in copper and deuterium
JF  - Zeitschrift für Physik C Particles and Fields
N2  - Results are presented on the ratios of the nucleon structure function in copper to deuterium from two separate experiments. The data confirm that the nucleon structure function,F 2, is different for bound nucleons than for the quasi-free ones in the deuteron. The redistribution in the fraction of the nucleon's momentum carried by quarks is investigated and it is found that the data are compatible with no integral loss of quark momenta due to nuclear effects.
Y1  - 1993
SN  - 1431-5858
N1  - European Muon Collaboration
VL  - 57
IS  - 2
SP  - 211
EP  - 218
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - A measurement of the spin asymmetry of the structure function g1 in deep inelastic muon-proton scattering
JF  - Physics Letters B
N2  - The spin asymmetry in deep inelastic scattering of longitudinally polarised muons by longitudinally polarised protons has been measured over a large x range (0.01<x<0.7). The spin-dependent structure function g1(x) for the proton has been determined and its integral over x found to be 0.114±0.012±0.026, in disagreement with the Ellis-Jaffe sum rule. Assuming the validity of the Bjorken sum rule, this result implies a significant negative value for the integral of g1 for the neutron. These values for the integrals of g1 lead to the conclusion that the total quark spin constitutes a rather small fraction of the spin of the nucleon.
Y1  - 1988
SN  - 0370-2693
N1  - European Muon Collaboration
VL  - 206
IS  - 2
SP  - 364
EP  - 370
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  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - A PET system based on data processing of free-running sampled pulses
JF  - 2001 IEEE Nuclear Science Symposium Conference Record, Vol. 2
N2  - Within the developments for the Crystal Clear small animal PET project (CLEARPET) a dual head PET system has been established. The basic principle is the early digitization of the detector pulses by free running ADCs. The determination of the γ-energy and also the coincidence detection is performed by data processing of the sampled pulses on the host computer. Therefore a time mark is attached to each pulse identifying the current cycle of the 40 MHz sampling clock. In order to refine the time resolution the pulse starting time is interpolated from the samples of the pulse rise. The detector heads consist of multichannel PMTs with a single LSO scintillator crystal coupled to each channel. For each PMT only one ADC is required. The position of an event is obtained separately from trigger signals generated for each single channel. An FPGA is utilized for pulse buffering, generation of the time mark and for the data transfer to the host via a fast I/O-interface.
Y1  - 2002
SN  - 1082-3654
SP  - 693
EP  - 694
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - A PET system with free running ADCs
JF  - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
N2  - A small PET system has been built up with two multichannel photomultipliers, which are attached to a matrix of 64 single LSO crystals each. The signal from each multiplier is being sampled continuously by a 12 bit ADC at a sampling frequency of 40 MHz. In case of a scintillation pulse a subsequent FPGA sends the corresponding set of samples together with the channel information and a time mark to the host computer. The data transfer is performed with a rate of 20 MB/s. On the host all necessary information is extracted from the data. The pulse energy is determined, coincident events are detected and multiple hits within one matrix can be identified. In order to achieve a narrow time window the pulse starting time is refined further than the resolution of the time mark (=25 ns) would allow. This is possible by interpolating between the pulse samples. First data obtained from this system will be presented. The system is part of developments for a much larger system and has been created to study the feasibility and performance of the technique and the hardware architecture.
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  - 18
EP  - 21
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - An investigation of the spin structure of the proton in deep inelastic scattering of polarised muons and polarised protons
JF  - Nuclear Physics B
N2  - The spin asymmetry in deep inelastic scattering of longitudinally polarised muons by longitudinally polarised protons has been measured in the range 0.01<×<0.7. The spin dependent structure function g1(x) for the proton has been determined and, combining the data with earlier SLAC measurements, its integral over x found to be 0.126±0.010(stat.)±0.015(syst.), in disagreement with the Ellis-Jaffe sum rule. Assuming the validity of the Biorken sum rule, this result implies a significant negative value for the integral of g1 for the neutron. These integrals lead to the conclusion, in the naïve quark parton model, that the total quark spin constitutes a rather small fraction of the spin of the nucleon. Results are also presented on the asymmetries in inclusive hadron production which are consistent with the above picture.
Y1  - 1989
SN  - 0550-3213
N1  - European Muon Collaboration
VL  - 328
IS  - 1
SP  - 1
EP  - 35
ER  - 
TY  - JOUR
A1  - Kleines, H.
A1  - Erki, I.
A1  - Ziemons, Karl
A1  - Zwoll, K.
ED  - Lehmann, Thomas
T1  - ATM- und Multimedia Pilotsystem im Rahmen des Projektes M-FIBRe Aufbau und Erfahrungen
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_001 Posterpräsentation
SP  - 241
EP  - 248
PB  - Verl. der. Augustinus-Buchh.
CY  - Aachen
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
A1  - Bruyndonckx, P.
A1  - Perez, J. M.
A1  - Pietrzyk, U.
A1  - Rato, P.
A1  - Tavernier, S.
T1  - Beyond ClearPET: Next Aims
JF  - 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro Symposium Proceedings ISBI 2008
N2  - The CRYSTAL CLEAR collaboration, in short CCC, is a consortium of 12 academic institutions, mainly from Europe, joining efforts in the area of developing instrumentation for nuclear medicine and medical imaging. In the framework of the CCC a high performance small animal PET system, called ClearPET, was developed by using new technologies in electronics and crystals in a phoswich arrangement combining two types of lutetium- based scintillator materials: LSO:Ce and LuYAP:Ce. Our next aim will be the development of hybrid image systems. Hybrid MR-PET imaging has many unique advantages for brain research. This has sparked a new research line within CCC for the development of novel MR-PET compatible technologies. MRI is not as sensitive as PET but PET has poorer spatial resolution than MRI. Two major advantages of PET are sensitivity and its ability to acquire metabolic information. To assess these innovations, the development of a 9.4T hybrid animal MR-PET scanner is proposed based on an existing 9.4T MR scanner that will be adapted to enable simultaneous acquisition of MR and PET data using cutting- edge technology for both MR and PET.
Y1  - 2008
SN  - 978-1-4244-2003-2
SP  - 1421
EP  - 1424
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Coincidence detection by digital processing of free-running sampled pulses
JF  - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
N2  - Coincident events in two scintillator crystals coupled to photomultipliers (PMT) are detected by processing just the digital data of the recorded pulses. For this purpose the signals from both PMTs are continuously sampled by free-running ADCs at a sampling rate of 40 MHz. For each sampled pulse the starting time is determined by processing the pulse data. Even a fairly simple interpolating algorithm results in a FWHM of about 2 ns.
Y1  - 2002
SN  - 0168-9002
VL  - 487
IS  - 3
SP  - 530
EP  - 534
ER  - 
TY  - JOUR
A1  - Jahnke, Siegfried
A1  - Menzel, Marion I.
A1  - Dusschoten, Dagmar van
A1  - Roeb, Gerhard W.
A1  - Bühler, Jonas
A1  - Minwuyelet, Senay
A1  - Blümler, Peter
A1  - Temperton, Vicky M.
A1  - Hombach, Thomas
A1  - Streun, Matthias
A1  - Beer, Simone
A1  - Khodaverdi, Maryam
A1  - Ziemons, Karl
A1  - Coenen, Heinz H.
A1  - Schurr, Ulrich
T1  - Combined MRI–PET dissects dynamic changes in plant structures and functions
JF  - The Plant Journal
N2  - Unravelling the factors determining the allocation of carbon to various plant organs is one of the great challenges of modern plant biology. Studying allocation under close to natural conditions requires non-invasive methods, which are now becoming available for measuring plants on a par with those developed for humans. By combining magnetic resonance imaging (MRI) and positron emission tomography (PET), we investigated three contrasting root/shoot systems growing in sand or soil, with respect to their structures, transport routes and the translocation dynamics of recently fixed photoassimilates labelled with the short-lived radioactive carbon isotope 11C. Storage organs of sugar beet (Beta vulgaris) and radish plants (Raphanus sativus) were assessed using MRI, providing images of the internal structures of the organs with high spatial resolution, and while species-specific transport sectoralities, properties of assimilate allocation and unloading characteristics were measured using PET. Growth and carbon allocation within complex root systems were monitored in maize plants (Zea mays), and the results may be used to identify factors affecting root growth in natural substrates or in competition with roots of other plants. MRI–PET co-registration opens the door for non-invasive analysis of plant structures and transport processes that may change in response to genomic, developmental or environmental challenges. It is our aim to make the methods applicable for quantitative analyses of plant traits in phenotyping as well as in understanding the dynamics of key processes that are essential to plant performance.
Y1  - 2009
SN  - 1365-313X
VL  - 59
IS  - 4
SP  - 634
EP  - 644
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Ziemons, Karl
T1  - Comparison of forward hadrons produced in muon interactions on nuclear targets and deuterium
JF  - Zeitschrift für Physik C Particles and Fields
N2  - Differential multiplicities of forward produced hadrons in deep inelastic muon scattering on nuclear targets have been compared with those from deuterium. The ratios are observed to increase towards unity as the virtual photon energy increases with no significant dependence on the other muon kinematic variables. The hadron transverse momentum distribution is observed to be broadened in nuclear targets. The dependence on the remaining hadron variables is investigated and the results are discussed in the framework of intranuclear interaction models and in the context of the EMC effect.
Y1  - 1991
SN  - 1431-5858
N1  - European Muon Collaboration
VL  - 52
IS  - 1
SP  - 1
EP  - 11
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  - 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  - 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  - Mosset, J.-B.
A1  - Devroede, O.
A1  - Krieguer, M.
A1  - Rey, M.
A1  - Vieira, J.-M.
A1  - Jung, J. H.
A1  - Kuntner, C.
A1  - Streun, M.
A1  - Ziemons, Karl
A1  - Auffray, E.
A1  - Sempere-Roldan, P.
A1  - Lecoq, P.
A1  - Bruyndonckx, P.
A1  - Loude, J.-F.
A1  - Tavernier, S.
A1  - Morcel, C.
T1  - Development of an optimized LSO/LuYAP phoswich detector head for the Lausanne ClearPET demonstrator
JF  - IEEE Transactions on Nuclear Science
N2  - This paper describes the LSO/LuYAP phoswich detector head developed for the ClearPET small animal PET scanner demonstrator that is under construction in Lausanne within the Crystal Clear Collaboration. The detector head consists of a dual layer of 8×8 LSO and LuYAP crystal arrays coupled to a multi-anode photomultiplier tube (Hamamatsu R7600-M64). Equalistion of the LSO/LuYAP light collection is obtained through partial attenuation of the LSO scintillation light using a thin aluminum deposit of 20-35 nm on LSO and appropriate temperature regulation of the phoswich head between 30°C to 60°C. At 511keV, typical FWHM energy resolutions of the pixels of a phoswich head amounts to (28±2)% for LSO and (25±2)% for LuYAP. The LSO versus LuYAP crystal identification efficiency is better than 98%. Six detector modules have been mounted on a rotating gantry. Axial and tangential spatial resolutions were measured up to 4 cm from the scanner axis and compared to Monte Carlo simulations using GATE. FWHM spatial resolution ranges from 1.3 mm on axis to 2.6 mm at 4 cm from the axis.
Y1  - 2006
SN  - 0018-9499
VL  - 53
IS  - 1
SP  - 25
EP  - 29
ER  - 
TY  - JOUR
A1  - Parl, C.
A1  - Larue, H.
A1  - Streun, M.
A1  - Ziemons, Karl
T1  - Double-side-readout technique for SiPM-matrices
JF  - 2010 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)
N2  - In our case the double-side-method is used to minimize the complexity of a matrix-readout. Here the number of channels is reduced to 2√N̅. It is also possible to benefit from the method in a single pixel readout system. One signal can be used to measure position and energy of the event, the other one can be applied to a fast trigger-circuit at the same time. In a next step we will investigate timing behavior and electrical crosstalk of the circuit.
Y1  - 2011
SN  - 1095-7863
SP  - 1486
EP  - 1487
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Weckesser, Matthias
A1  - Hufnagel, Andreas
A1  - Ziemons, Karl
A1  - Grießmeier, Martin
A1  - Sonnenberg, Frank
A1  - Hackländer, Thomas
A1  - Langen, Karl-J.
A1  - Holschbach, Markus
A1  - Elger, Christian E.
A1  - Müller-Gärtner, Hans-W.
T1  - Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy
JF  - European Journal of Nuclear Medicine
N2  - 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.
Y1  - 1997
SN  - 1619-7089
VL  - 24
IS  - 9
SP  - 1156
EP  - 1161
ER  -