| 1. |
- Hegyesi, G., et al.
(författare)
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Development of an FPGA-based data acquisition module for small animal PET
- 2004
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Ingår i: 2004 IEEE Nuclear Science Symposium Conference Record. - 0780387007 ; , s. 2957-2961
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Konferensbidrag (refereegranskat)abstract
- We report on the design of a DAQ module for a small animal PET camera developed at our institutes. During the design an important guideline was to develop a system which is built up from strictly identical DAQ modules, and which has no built-in hardware limitation on the maximum number of modules. The developed DAQ module comprises of an LSO scintillator crystal block, a position sensitive PMT, analog signal conditioning circuits, a digitizer, an FPGA for digital signal processing and a communication module through which the collected data is sent to a cluster of computers for post processing and storage. Instead of implementing hardware coincidence detection between the modules we attach a precise time-stamp to each event in our design, and the coincidence is determined by the data collecting computers during the post processing. The digital CFD algorithm implemented in the FPGA gives a time resolution of 2 to 3 ns FWHM for real detector signals.
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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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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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- Valastyán, Iván, et al.
(författare)
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Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 571:1-2, s. 219-222
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Tidskriftsartikel (refereegranskat)abstract
- Iterative reconstruction methods are commonly used to obtain images with high resolution and good signal-to-noise ratio in nuclear imaging. The aim of this work was to develop a scalable, fast, cluster based, fully 3-D iterative image reconstruction package for our small animal PET camera, the miniPET. The reconstruction package is developed to determine the 3-D radioactivity distribution from list mode type of data sets and it can also simulate noise-free projections of digital phantoms. We separated the system matrix generation and the fully 3-D iterative reconstruction process. As the detector geometry is fixed for a given camera, the system matrix describing this geometry is calculated only once and used for every image reconstruction, making the process much faster. The Poisson and the random noise sensitivity of the ML-EM iterative algorithm were studied for our small animal PET system with the help of the simulation and reconstruction tool. The reconstruction tool has also been tested with data collected by the miniPET from a line and a cylinder shaped phantom and also a rat.
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