| 1. |
- Mason, P, et al.
(författare)
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Octupole signatures in Ba-124,Ba-125
- 2005
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1729-S1733
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Tidskriftsartikel (refereegranskat)abstract
- The gamma decay of the nuclei Ba-121,Ba-125 has been investigated with the EUROBALL array, using the reaction Ni-64+Ni-64 at E-beam = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus Ba-125, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J(pi) = 3(-) level of the nucleus Ba-124 has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions.
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| 2. |
- Hegyesi, G., et al.
(författare)
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Ethernet based distributed data acquisition system for a small animal PET
- 2006
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 53:4, s. 2112-2117
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Tidskriftsartikel (refereegranskat)abstract
- We report on the design of a small animal PET scanner being developed at our institutes. The existing setup is the first version of the miniPET machine consisting of four detector modules. Each detector module consists of an 8 x 8 LSO scintillator crystal block, a position sensitive photomultiplier, a digitizer including a digital signal processing board and an Ethernet interface board. There is no hardware coincidence detection implemented in the system and coincidence is determined based on a time stamp attached to every event by a digital CFD algorithm. The algorithm is implemented in the digital signal processing board and generates a time stamp with a coincidence resolution of less than 2 us. The data acquisition system is based on Ethernet network and is highly scalable in size and performance.
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| 3. |
- Imrek, J., et al.
(författare)
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Internals and evaluation of the miniPET-II detector module
- 2007
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Ingår i: 2007 IEEE Nuclear Science Symposium Conference Record. - 1424409233 - 9781424409235 ; , s. 2930-2932
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Konferensbidrag (refereegranskat)abstract
- We report on the architecture of the System-on-Module (SoM) developed by our group for miniPET-II, the second version of our small animal PET scanner. The paper describes the hardware and software implementation details of the SoM we realized inside the miniPET-II detector module, the embedded Linux operation system, and the the initial results of bandwidth test measurements on the assembled SoM. Detailed description is given on the interfacing of the updated miniPET IP Core to the SoM, on the efficient data transfer method that implements device-to-device DMA transfer, and on the usage of User Datagram Protocol (UDP/IP) for high speed data transfer.
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| 4. |
- Kis, S. A., et al.
(författare)
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Comparison of Monte Carlo simulated and measured performance parameters of miniPET scanner
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 571:02-jan, s. 449-452
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Tidskriftsartikel (refereegranskat)abstract
- In vivo imaging of small laboratory animals is a valuable tool in the development of new drugs. For this purpose, miniPET, an easy to scale modular small animal PET camera has been developed at our institutes. The system has four modules, which makes it possible to rotate the whole detector system around the axis of the field of view. Data collection and image reconstruction are performed using a data acquisition (DAQ) module with Ethernet communication facility and a computer cluster of commercial PCs. Performance tests were carried out to deter-mine system parameters, such as energy resolution, sensitivity and noise equivalent count rate. A modified GEANT4-based GATE Monte Carlo software package was used to simulate PET data analogous to those of the performance measurements. GATE was run on a Linux cluster of 10 processors (64 bit, Xeon with 3.0 GHz) and controlled by a SUN grid engine. The application of this special computer cluster reduced the time necessary for the simulations by an order of magnitude. The simulated energy spectra, maximum rate of true coincidences and sensitivity of the camera were in good agreement with the measured parameters.
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| 5. |
- Kis, S. A., et al.
(författare)
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Performance Characteristics of a miniPET Scanner Dedicated to Small Animal Imaging
- 2005
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Ingår i: 2005 IEEE Nuclear Science Symposium Conference Record. - 0780392213 - 9780780392212 ; , s. 1645-1648
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Konferensbidrag (refereegranskat)abstract
- An easy to scale up modular PET scanner was developed for imaging small animals. Energy resolution, spatial resolution and count rate performance were determined as system parameters. The configuration provided an average energy resolution of 19.6 % and the image resolution ranges was 1.5 to 2.3 mm in radial direction. The sensitivity of the miniPET was 1.08 cps/kBq as determined using a point source. In addition, results of rat brain scan performed with FDG are given to characterize imaging capability of the system. The displayed data document that the miniPET scanner supports good quality brain imaging of small animals.
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| 6. |
- Imrek, J., et al.
(författare)
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Development of an improved detector module for miniPET-II
- 2007
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Ingår i: 2006 IEEE Nuclear Science Symposium Conference Record. - : IEEE. - 1424405610 - 9781424405619 ; , s. 3037-3040
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Konferensbidrag (refereegranskat)abstract
- We present a new detector module developed for miniPET-II, the second generation of the miniPET small animal PET scanners. The improved module features new hardware components for better performance: LySO crystal material, increased number of crystal segments, Hamamatsu H9500 PSPMT, Xilinx Virtex-4 FPGA and Gigabit Ethernet. However, the principle of operation is the same: no hardware coincidence detection is implemented, data is acquired in list mode and transfered over an Ethernet network. The resulting new module is more suitable for full ring configurations.
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| 7. |
- Simon, A., et al.
(författare)
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High spatial resolution measurement of depth-of-interaction of a PET LSO crystal
- 2005
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 546:1-2, s. 33-36
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Tidskriftsartikel (refereegranskat)abstract
- A new type of experimental technique to investigate the depth- of-interaction (DOI) dependence in small scintillator elements designed for high-resolution animal PET is tested. An Oxford-type nuclear microprobe was used to irradiate a lutetium oxyorthosilicate (LSO) crystal (2 x 2 x 10 mm) with a highly focused, (few micrometers diam.), 2 MeV He+ beam. Pulse height spectra from a PMT attached to one end of the LSO crystal were collected in list mode. By scanning the beam over the crystal high-resolution 2D-images are generated and thus the DOI effect in the scintillator could be investigated. The obtained results of the overall DOI dependence confirm previous findings using gamma-rays. Since the present experimental setup allows obtaining data with several orders of magnitude better spatial resolution than with collimated gamma-beam, the method can be applied for variety of problems where high spatial resolution is required.
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| 8. |
- Valastyán, Iván, et al.
(författare)
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Experimental scanner setup from miniPET II detector module
- 2009
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Ingår i: 2008 IEEE Nuclear Science SYmposium Conference Record. - 9781424427147 ; , s. 3121-3124
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The PET technique is widely used in human clinical studies and recent developments of image resolution has made it suitable for small animal research. The second generation of our PET scanner consists of 12 detector modules and has a field of view large enough to image mice and rats. Parameters of the incoming data are extracted by Digital Signal Processing in the detector modules and a System-on-Module is used to transmit the data through an Ethernet network for storage and reconstruction. The experimental scanner setup described in this paper was constructed in order to investigate the applicability of the developed detector modules in a full ring small animal PET camera. The preliminary results of the system are also presented.
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