@article{WedrowskiBruyndonckxTavernieretal.2009, author = {Wedrowski, M. and Bruyndonckx, P. and Tavernier, S. and Zhi, L. and Dang, J. and Mendes, P. R. and Perez, J. M. and Ziemons, Karl}, title = {Robustness of neural networks algorithm for gamma detection in monolithic block detector, positron emission tomography}, series = {2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)}, journal = {2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)}, isbn = {1082-3654}, pages = {2625 -- 2628}, year = {2009}, abstract = {The monolithic scintillator block approach for gamma detection in the Positron Emission Tomography (PET) avoids estimating Depth of Interaction (DOI), reduces dead zones in detector and diminishes costs of detector production. Neural Networks (NN) are very efficient to determine the entrance point of a gamma incident on a scintillator block. This paper presents results on the robustness of the spatial resolution as a function of the random fraction in the data, temperature and HV fluctuations. This is important when implementing the method in a real scanner. Measurements were done with two Hamamatsu S8550 APD arrays, glued on a 20 {\~A}— 20 {\~A}— 10 mm3 monolithic LSO crystal block.}, language = {en} } @article{BoeckerKuwertLangenetal.1994, author = {Boecker, Henning and Kuwert, Torsten and Langen, Karl-J. and Lange, Herwig W. and Czech, Norbert and Ziemons, Karl and Herzog, Hans and Shikare, Shekar and Weindl, Anton and Feinendegen, Ludwig E.}, title = {SPECT with HMPAO compared to PET with FDG in Huntington disease}, series = {Journal of Computer Assisted Tomography}, volume = {18}, journal = {Journal of Computer Assisted Tomography}, number = {4}, isbn = {1532-3145}, pages = {542 -- 548}, year = {1994}, language = {en} } @article{HeinrichBlumBussmannetal.2002, author = {Heinrich, U. and Blum, A. and Bussmann, N. and Engels, R. and Kemmerling, G. and Weber, S. and Ziemons, Karl}, title = {Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials}, series = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {486}, journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, number = {1-2}, issn = {0168-9002}, pages = {60 -- 66}, year = {2002}, abstract = {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.}, language = {en} } @article{ZiemonsBerghoffLanskeetal.1988, author = {Ziemons, Karl and Berghoff, G. and Lanske, D. and Schultze, K.}, title = {Strangeness production in deep inelastic muon-nucleon scattering}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, volume = {23}, journal = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, number = {5}, isbn = {0420-0195}, pages = {T309 -- T309}, year = {1988}, language = {en} } @article{StreunBrandenburgBroekeletal.2004, author = {Streun, M. and Brandenburg, G. and Br{\"o}kel, M. and Fuss, L. and Larue, H. and Parl, C. and Zimmermann, E. and Ziemons, Karl and Halling, H.}, title = {The ClearPET data acquisition}, series = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5}, journal = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5}, issn = {1082-3654}, pages = {3097 -- 3100}, year = {2004}, abstract = {Within the Crystal Clear Collaboration a modular system for a small animal PET scanner (ClearPET™) has been developed. The modularity allows the assembly of scanners of different sizes and characteristics in order to fit the specific needs of the individual member institutions. Now a first demonstrator is being completed in Julich. The system performs depth of interaction detection by using a phoswich arrangement combining LSO and LuYAP scintillators which are coupled to multi-channel photomultipliers (PMTs). A free-running ADC digitizes the signal from the PMT and the complete scintillation pulses are sampled by an FPGA and sent with 20 MB/S to a PC for preprocessing. The pulse provides information about the gamma energy and the scintillator material which identifies the interaction layer. Furthermore, the exact pulse starting time is obtained from the sampled data. This is important as no hardware coincidence detection is implemented. All single events are recorded and coincidences are identified by software. An advantage of that is that the coincidence window and the dimensions of the field of view can be adjusted easily. The ClearPET™ demonstrator is equipped with 10240 crystals on 80 PMTs. This paper presents an overview of the data acquisition system.}, language = {en} } @article{AuffrayBruyndonckxDevroedeetal.2004, author = {Auffray, E. and Bruyndonckx, P. and Devroede, O. and Fedorov, A. and Ziemons, Karl}, title = {The ClearPET project}, series = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {527}, journal = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, number = {1-2}, isbn = {0168-9002}, pages = {171 -- 174}, year = {2004}, abstract = {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.}, language = {en} } @article{ZiemonsAuffrayBarbieretal.2004, author = {Ziemons, Karl and Auffray, E. and Barbier, R. and Brandenburg, G.}, title = {The ClearPET TM LSO/LuYAP phoswich scanner: a high performance small animal PET system}, series = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 3}, journal = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 3}, issn = {1082-3654}, pages = {1728 -- 1732}, year = {2004}, abstract = {A 2nd generation high performance small animal PET scanner, called ClearPET™, has been designed and a first prototype is built by working groups of the Crystal Clear Collaboration (CCC). In order to achieve high sensitivity and maintain good uniform spatial resolution over the field of view in high resolution PET systems, it is necessary to extract the depth of interaction (DOI) information and correct for spatial degradation. The design of the first ClearPET™ Demonstrator based on the use of the multi-anode photomultiplier tube (Hamamatsu R7600-M64) and a LSO/LuYAP phoswich matrix. The two crystal layers of 8*8 crystals (2*2*10 mm3) are stacked on each other and mounted without light guide as one to one on the PMT. A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the crystal ring is 137 mm, the axial detector length is 110 mm. The PMT 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. The measurements have been done using the first LSO/LuYAP detector cassettes.}, language = {en} } @article{ZiemonsAchtenAuffrayetal.2004, author = {Ziemons, Karl and Achten, R. and Auffray, E. and M{\"u}ller-Veggian, Mattea}, title = {The ClearPET™ neuro scanner: a dedicated LSO/LuYAP phoswich small animal PET scanner}, series = {2004 IEEE Nuclear Science Symposium conference record : Nuclear Science Symposium, Medical Imaging Conference ; 16 - 22 October 2004, Rome, Italy ; [including the Symposium on Nuclear Power System (SNPS), 14th Room Temperature Semiconductor X- and Gamma-Ray Detectors Workshop and special focus workshops] / NPSS, Nuclear \& Plasma Sciences Society. Guest ed.: J. Anthony Seibert}, journal = {2004 IEEE Nuclear Science Symposium conference record : Nuclear Science Symposium, Medical Imaging Conference ; 16 - 22 October 2004, Rome, Italy ; [including the Symposium on Nuclear Power System (SNPS), 14th Room Temperature Semiconductor X- and Gamma-Ray Detectors Workshop and special focus workshops] / NPSS, Nuclear \& Plasma Sciences Society. Guest ed.: J. Anthony Seibert}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, issn = {1082-3654}, pages = {2430 -- 2433}, year = {2004}, language = {en} } @article{ZiemonsAuffrayBarbieretal.2005, author = {Ziemons, Karl and Auffray, E. and Barbier, R. and Brandenburg, G. and Bruyndonckx, P.}, title = {The ClearPET™ project: Development of a 2nd generation high-performance small animal PET scanner}, series = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {537}, journal = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, number = {1-2}, issn = {0168-9002}, pages = {307 -- 311}, year = {2005}, abstract = {Second generation high-performance PET scanners, called ClearPET™1, have been developed by working groups of the Crystal Clear Collaboration (CCC). High sensitivity and high spatial resolution for the ClearPET camera is achieved by using a phoswich arrangement combining two different types of lutetium-based scintillator materials: LSO from CTI and LuYAP:Ce from the CCC (ISTC project). In a first ClearPET prototype, phoswich arrangements of 8×8 crystals of 2×2×10 mm3 are coupled to multi-channel photomultiplier tubes (Hamamatsu R7600). A unit of four PMTs arranged in-line represents one of 20 sectors of the ring design. The opening diameter of the ring is 120 mm, the axial detector length is 110 mm.The PMT pulses are digitized by free-running ADCs and digital data processing determines the gamma energy, the phoswich layer and even the exact pulse starting time, which is subsequently used for coincidence detection. The gantry allows rotation of the detector modules around the field of view. Preliminary data shows a correct identification of the crystal layer about (98±1)\%. Typically the energy resolution is (23.3±0.5)\% for the luyap layer and (15.4±0.4)\% for the lso layer. early studies showed the timing resolution of 2 ns FWHM and 4.8 ns FWTM. the intrinsic spatial resolution ranges from 1.37 mm to 1.61 mm full-width of half-maximum (FWHM) with a mean of 1.48 mm FWHM. further improvements in image and energy resolution are expected when the system geometry is fully modeled.}, language = {en} } @article{HerzogPietrzykShahetal.2010, author = {Herzog, Hans and Pietrzyk, Uwe and Shah, N. Jon and Ziemons, Karl}, title = {The current state, challenges and perspectives of MR-PET}, series = {Neuroimage}, volume = {49}, journal = {Neuroimage}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2009.10.036}, pages = {2072 -- 2082}, year = {2010}, abstract = {Following the success of PET/CT during the last decade and the recent increasing proliferation of SPECT/CT, another hybrid imaging instrument has been gaining more and more interest: MR-PET. First combined, simultaneous PET and MR studies carried out in small animals demonstrated the feasibility of the new approach. Concurrently, some prototypes of an MR-PET scanner for simultaneous human brain studies have been built, their performance is being tested and preliminary applications have already been shown. Through this pioneering work, it has become clear that advances in the detector design are necessary for further optimization. Recently, the different issues related to the present state and future prospects of MR-PET were presented and discussed during an international 2-day workshop at the Forschungszentrum J{\"u}lich, Germany, held after, and in conjunction with, the 2008 IEEE Nuclear Science Symposium and Medical Imaging Conference in Dresden, Germany on October 27-28, 2008. The topics ranged from small animal MR-PET imaging to human MR-BrainPET imaging, new detector developments, challenges/opportunities for ultra-high field MR-PET imaging and considerations of possible future research and clinical applications. This report presents a critical summary of the contributions made to the workshop.}, language = {en} }