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SPECT and SPECT/CT. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00008-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Parach AA, Rajabi H. A comparison between GATE4 results and MCNP4B published data for internal radiation dosimetry. Nuklearmedizin 2017; 50:122-33. [DOI: 10.3413/nukmed-0363-10-10] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 01/13/2011] [Indexed: 11/20/2022]
Abstract
SummaryAim: GATE, has been designed as upper layer of the GEANT4 toolkit for nuclear medicine application including internal dosimetry. However, its results have not been fully compared to the well-developed codes and anthropomorphic voxel phantoms have never been used with GATE/GEANT for internal dosimetry. The aim of present study was to compare the internal dose calculated by GATE/GEANT with the MCNP4B published data. Methods: The Zubal phantom was used to model a typical adult male. Activity was assumed uniformly distributed in liver, kidneys, lungs, spleen, pancreas and adrenals. GATE/ GEANT Monte Carlo package was used for estimation of doses in the phantom. Simulations were performed for photon energy of 0.01–1 MeV and mono-energetic electrons of 935 keV. Specific absorbed fractions for photons and S-factors for electrons were calculated. Results: On average, GATE/GEANT produces higher photon SAF (Specific Absorbed Fraction) values (+2.7%) for self-absorption and lower values (-2.9%) for cross-absorption. The difference was higher for paired organs particularly lungs. Moreover the photon SAF values for lungs as source organ at the energy of 200 and 500 keV was considerably higher with MCNP4B compared to GATE. Conclusion: Despite of differences between the GATE4 and MCNP4B, the results can be considered ensuring. This may be considered as validation of GATE/GEANT as a proprietary code in nuclear medicine for radionuclide dosimetry applications.
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Karamat MI, Farncombe TH. A Comparison Between GATE and Accelerated Convolution-Based Forced Detection SIMIND for Low- and Medium-Energy Collimators: A Simulation Study. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2017. [DOI: 10.1109/tns.2016.2634419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Elschot M, Smits MLJ, Nijsen JFW, Lam MGEH, Zonnenberg BA, van den Bosch MAAJ, Viergever MA, de Jong HWAM. Quantitative Monte Carlo-based holmium-166 SPECT reconstruction. Med Phys 2014; 40:112502. [PMID: 24320461 DOI: 10.1118/1.4823788] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Quantitative imaging of the radionuclide distribution is of increasing interest for microsphere radioembolization (RE) of liver malignancies, to aid treatment planning and dosimetry. For this purpose, holmium-166 ((166)Ho) microspheres have been developed, which can be visualized with a gamma camera. The objective of this work is to develop and evaluate a new reconstruction method for quantitative (166)Ho SPECT, including Monte Carlo-based modeling of photon contributions from the full energy spectrum. METHODS A fast Monte Carlo (MC) simulator was developed for simulation of (166)Ho projection images and incorporated in a statistical reconstruction algorithm (SPECT-fMC). Photon scatter and attenuation for all photons sampled from the full (166)Ho energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled using precalculated convolution kernels. Phantom experiments were performed to quantitatively evaluate image contrast, image noise, count errors, and activity recovery coefficients (ARCs) of SPECT-fMC in comparison with those of an energy window-based method for correction of down-scattered high-energy photons (SPECT-DSW) and a previously presented hybrid method that combines MC simulation of photopeak scatter with energy window-based estimation of down-scattered high-energy contributions (SPECT-ppMC+DSW). Additionally, the impact of SPECT-fMC on whole-body recovered activities (A(est)) and estimated radiation absorbed doses was evaluated using clinical SPECT data of six (166)Ho RE patients. RESULTS At the same noise level, SPECT-fMC images showed substantially higher contrast than SPECT-DSW and SPECT-ppMC+DSW in spheres ≥ 17 mm in diameter. The count error was reduced from 29% (SPECT-DSW) and 25% (SPECT-ppMC+DSW) to 12% (SPECT-fMC). ARCs in five spherical volumes of 1.96-106.21 ml were improved from 32%-63% (SPECT-DSW) and 50%-80% (SPECT-ppMC+DSW) to 76%-103% (SPECT-fMC). Furthermore, SPECT-fMC recovered whole-body activities were most accurate (A(est) = 1.06 × A - 5.90 MBq, R(2) = 0.97) and SPECT-fMC tumor absorbed doses were significantly higher than with SPECT-DSW (p = 0.031) and SPECT-ppMC+DSW (p = 0.031). CONCLUSIONS The quantitative accuracy of (166)Ho SPECT is improved by Monte Carlo-based modeling of the image degrading factors. Consequently, the proposed reconstruction method enables accurate estimation of the radiation absorbed dose in clinical practice.
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Affiliation(s)
- Mattijs Elschot
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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Elschot M, Lam MGEH, van den Bosch MAAJ, Viergever MA, de Jong HWAM. Quantitative Monte Carlo-based 90Y SPECT reconstruction. J Nucl Med 2013; 54:1557-63. [PMID: 23907758 DOI: 10.2967/jnumed.112.119131] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED The evaluation of radiation absorbed doses in tumorous and healthy tissues is of increasing interest for (90)Y microsphere radioembolization of liver malignancies. The objectives of this work were to introduce and validate a new reconstruction method for quantitative (90)Y bremsstrahlung SPECT to improve posttreatment dosimetry. METHODS A fast Monte Carlo simulator was adapted for (90)Y and incorporated into a statistical reconstruction algorithm (SPECT-MC). Photon scatter and attenuation for all photons sampled from the full (90)Y energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled with precalculated convolution kernels. The National Electrical Manufacturers Association 2007/International Electrotechnical Commission 2008 image quality phantom was used to quantitatively evaluate the performance of SPECT-MC in comparison with those of state-of-the-art clinical SPECT reconstruction and PET. The liver radiation absorbed doses estimated by SPECT, PET, and SPECT-MC were evaluated in 5 patients consecutively treated with radioembolization. RESULTS In comparison with state-of-the-art clinical (90)Y SPECT reconstruction, SPECT-MC substantially improved image contrast (e.g., from 25% to 88% for the 37-mm sphere) and decreased the mean residual count error in the lung insert (from 73% to 15%) at the cost of higher image noise. Image noise and the mean count error were lower for SPECT-MC than for PET. Image contrast was higher in the larger spheres (diameter of ≥28 mm) but lower in the smaller spheres (≤22 mm) for SPECT-MC than for PET. In the clinical study, mean absorbed dose estimates in liver regions with high absorbed doses were consistently higher for SPECT-MC than for SPECT (P = 0.0625) and consistently higher for SPECT-MC than for PET (P = 0.0625). CONCLUSION The quantitative accuracy of (90)Y bremsstrahlung SPECT is substantially improved by Monte Carlo-based modeling of the image-degrading factors. Consequently, (90)Y bremsstrahlung SPECT may be used as an alternative to (90)Y PET.
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Affiliation(s)
- Mattijs Elschot
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
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El Bitar Z, Huesman RH, Boutchko R, Bekaert V, Brasse D, Gullberg GT. A detector response function design in pinhole SPECT including geometrical calibration. Phys Med Biol 2013; 58:2395-411. [PMID: 23492938 DOI: 10.1088/0031-9155/58/7/2395] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Clinical single photon emission computed tomography (SPECT) equipped with pinhole collimators have a magnification factor that results in high spatial resolution images for small animal imaging. Using Monte Carlo simulations to model the acquisition process and the propagation of the photons from their point of emission to their detection point then integrating the model into an iterative reconstruction algorithm improves the signal-to-noise ratio, the contrast and the spatial resolution in the reconstructed images. However, pinhole SPECT systems are known to be very sensitive to geometrical misalignments. Geometrical misalignments are defined as the radial or axial shift of the collimator pinhole and/or twist and tilt of the detector heads and are introduced in the system each time the collimation device is changed (pinhole to parallel holes or vice versa). In this work, we present a flexible detector response function table (DRFT) design that takes into account the geometrical misalignments and avoids performing new Monte Carlo simulations for each exam in order to calculate a geometrical study-dependent system matrix. The utilization of the DRFT for the calculation of the system matrix speeds up its computation time by two orders of magnitude making it acceptable for preclinical and clinical applications.
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Affiliation(s)
- Z El Bitar
- IPHC, Université de Strasbourg, 23 rue du loess, F-67037 Strasbourg, France.
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Chun SY, Fessler JA, Dewaraja YK. Correction for collimator-detector response in SPECT using point spread function template. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:295-305. [PMID: 23086521 PMCID: PMC3619230 DOI: 10.1109/tmi.2012.2225441] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Compensating for the collimator-detector response (CDR) in SPECT is important for accurate quantification. The CDR consists of both a geometric response and a septal penetration and collimator scatter response. The geometric response can be modeled analytically and is often used for modeling the whole CDR if the geometric response dominates. However, for radionuclides that emit medium or high-energy photons such as I-131, the septal penetration and collimator scatter response is significant and its modeling in the CDR correction is important for accurate quantification. There are two main methods for modeling the depth-dependent CDR so as to include both the geometric response and the septal penetration and collimator scatter response. One is to fit a Gaussian plus exponential function that is rotationally invariant to the measured point source response at several source-detector distances. However, a rotationally-invariant exponential function cannot represent the star-shaped septal penetration tails in detail. Another is to perform Monte-Carlo (MC) simulations to generate the depth-dependent point spread functions (PSFs) for all necessary distances. However, MC simulations, which require careful modeling of the SPECT detector components, can be challenging and accurate results may not be available for all of the different SPECT scanners in clinics. In this paper, we propose an alternative approach to CDR modeling. We use a Gaussian function plus a 2-D B-spline PSF template and fit the model to measurements of an I-131 point source at several distances. The proposed PSF-template-based approach is nearly non-parametric, captures the characteristics of the septal penetration tails, and minimizes the difference between the fitted and measured CDR at the distances of interest. The new model is applied to I-131 SPECT reconstructions of experimental phantom measurements, a patient study, and a MC patient simulation study employing the XCAT phantom. The proposed model yields up to a 16.5 and 10.8% higher recovery coefficient compared to the results with the conventional Gaussian model and the Gaussian plus exponential model, respectively.
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Affiliation(s)
- Se Young Chun
- Department of Electrical Engineering and Computer Science and Radiology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Jeffrey A. Fessler
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109 USA
| | - Yuni K. Dewaraja
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109 USA
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Sohlberg AO, Kajaste MT. Fast Monte Carlo-simulator with full collimator and detector response modelling for SPECT. Ann Nucl Med 2011; 26:92-8. [PMID: 22033783 DOI: 10.1007/s12149-011-0550-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 10/13/2011] [Indexed: 10/16/2022]
Abstract
OBJECTIVE Monte Carlo (MC)-simulations have proved to be a valuable tool in studying SPECT-reconstruction algorithms. Despite their popularity, the use of Monte Carlo-simulations is still often limited by their large computation demand. This is especially true in situations where full collimator and detector modelling with septal penetration, scatter and X-ray fluorescence needs to be included. This paper presents a rapid and simple MC-simulator, which can effectively reduce the computation times. METHODS The simulator was built on the convolution-based forced detection principle, which can markedly lower the number of simulated photons. Full collimator and detector response look-up tables are pre-simulated and then later used in the actual MC-simulations to model the system response. The developed simulator was validated by comparing it against (123)I point source measurements made with a clinical gamma camera system and against (99m)Tc software phantom simulations made with the SIMIND MC-package. RESULTS The results showed good agreement between the new simulator, measurements and the SIMIND-package. The new simulator provided near noise-free projection data in approximately 1.5 min per projection with (99m)Tc, which was less than one-tenth of SIMIND's time. CONCLUSION The developed MC-simulator can markedly decrease the simulation time without sacrificing image quality.
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Affiliation(s)
- Antti O Sohlberg
- Department of Clinical Physiology and Nuclear Medicine, Joint Authority for Päijät-Häme Social and Health Care, Lahti, Finland.
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Hutton BF, Buvat I, Beekman FJ. Review and current status of SPECT scatter correction. Phys Med Biol 2011; 56:R85-112. [PMID: 21701055 DOI: 10.1088/0031-9155/56/14/r01] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Goorden MC, van der Have F, Kreuger R, Beekman FJ. An efficient simulator for pinhole imaging of PET isotopes. Phys Med Biol 2011; 56:1617-34. [DOI: 10.1088/0031-9155/56/6/007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rault E, Staelens S, Van Holen R, De Beenhouwer J, Vandenberghe S. Accurate Monte Carlo modelling of the back compartments of SPECT cameras. Phys Med Biol 2010; 56:87-104. [DOI: 10.1088/0031-9155/56/1/006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bullich S, Cot A, Gallego J, Gunn R, Suárez M, Pavía J, Ros D, Laruelle M, Catafau A. Impact of scatter correction on D2 receptor occupancy measurements using 123I-IBZM SPECT: Comparison to 11C-Raclopride PET. Neuroimage 2010; 50:1511-8. [DOI: 10.1016/j.neuroimage.2010.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 12/28/2009] [Accepted: 01/07/2010] [Indexed: 10/20/2022] Open
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Descourt P, Carlier T, Du Y, Song X, Buvat I, Frey EC, Bardies M, Tsui BMW, Visvikis D. Implementation of angular response function modeling in SPECT simulations with GATE. Phys Med Biol 2010; 55:N253-66. [PMID: 20393239 DOI: 10.1088/0031-9155/55/9/n04] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Among Monte Carlo simulation codes in medical imaging, the GATE simulation platform is widely used today given its flexibility and accuracy, despite long run times, which in SPECT simulations are mostly spent in tracking photons through the collimators. In this work, a tabulated model of the collimator/detector response was implemented within the GATE framework to significantly reduce the simulation times in SPECT. This implementation uses the angular response function (ARF) model. The performance of the implemented ARF approach has been compared to standard SPECT GATE simulations in terms of the ARF tables' accuracy, overall SPECT system performance and run times. Considering the simulation of the Siemens Symbia T SPECT system using high-energy collimators, differences of less than 1% were measured between the ARF-based and the standard GATE-based simulations, while considering the same noise level in the projections, acceleration factors of up to 180 were obtained when simulating a planar 364 keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a four-head SPECT simulation of a realistic Jaszczak phantom filled with iodine-131, with a resulting acceleration factor of 100. In conclusion, the implementation of an ARF-based model of collimator/detector response for SPECT simulations within GATE significantly reduces the simulation run times without compromising accuracy.
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Affiliation(s)
- P Descourt
- INSERM, U650, LaTIM, IFR SclnBioS, Université de Brest, CHU Brest, Brest, F-29200, France
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Van Holen R, Staelens S, Vandenberghe S. SPECT imaging of high energy isotopes and isotopes with high energy contaminants with rotating slat collimators. Med Phys 2009; 36:4257-67. [DOI: 10.1118/1.3177312] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Liu S, King MA, Brill AB, Stabin MG, Farncombe TH. Convolution-Based Forced Detection Monte Carlo Simulation Incorporating Septal Penetration Modeling. IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2008; 55:967-974. [PMID: 20814585 PMCID: PMC2931277 DOI: 10.1109/tns.2008.924079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In SPECT imaging, photon transport effects such as scatter, attenuation and septal penetration can negatively affect the quality of the reconstructed image and the accuracy of quantitation estimation. As such, it is useful to model these effects as carefully as possible during the image reconstruction process. Many of these effects can be included in Monte Carlo (MC) based image reconstruction using convolution-based forced detection (CFD). With CFD Monte Carlo (CFD-MC), often only the geometric response of the collimator is modeled, thereby making the assumption that the collimator materials are thick enough to completely absorb photons. However, in order to retain high collimator sensitivity and high spatial resolution, it is required that the septa be as thin as possible, thus resulting in a significant amount of septal penetration for high energy radionuclides. A method for modeling the effects of both collimator septal penetration and geometric response using ray tracing (RT) techniques has been performed and included into a CFD-MC program. Two look-up tables are pre-calculated based on the specific collimator parameters and radionuclides, and subsequently incorporated into the SIMIND MC program. One table consists of the cumulative septal thickness between any point on the collimator and the center location of the collimator. The other table presents the resultant collimator response for a point source at different distances from the collimator and for various energies. A series of RT simulations have been compared to experimental data for different radionuclides and collimators. Results of the RT technique matches experimental data of collimator response very well, producing correlation coefficients higher than 0.995. Reasonable values of the parameters in the lookup table and computation speed are discussed in order to achieve high accuracy while using minimal storage space for the look-up tables. In order to achieve noise-free projection images from MC, it is seen that the inclusion of the RT implementation for septal penetration increases the speed of the simulation by a factor of about 7,500 compared to the conventional SIMIND MC program.
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Affiliation(s)
- Shaoying Liu
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Michael A. King
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 USA
| | - Aaron B. Brill
- Department of Radiology, Vanderbilt University, Nashville, TN 37240 USA
| | - Michael G. Stabin
- Department of Radiology, Vanderbilt University, Nashville, TN 37240 USA
| | - Troy H. Farncombe
- Department of Nuclear Medicine, Hamilton Health Sciences, Hamilton, ON L8R 1M8, Canada
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De Beenhouwer J, Staelens S, Vandenberghe S, Lemahieu I. Acceleration of GATE SPECT simulations. Med Phys 2008; 35:1476-85. [DOI: 10.1118/1.2885370] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Staelens SG, de Wit TC, Lemahieu IA, Beekman FJ. Degradation of myocardial perfusion SPECT images caused by contaminants in thallous (201Tl) chloride. Eur J Nucl Med Mol Imaging 2008; 35:922-32. [DOI: 10.1007/s00259-008-0719-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Accepted: 01/04/2008] [Indexed: 11/24/2022]
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