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Author |
Ballester, F.; Granero, D.; Perez-Calatayud, J.; Venselaar, J.L.M.; Rivard, M.J. |
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Title |
Study of encapsulated Tm-170 sources for their potential use in brachytherapy |
Type |
Journal Article |
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Year |
2010 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
37 |
Issue |
4 |
Pages |
1629-1637 |
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Keywords |
brachytherapy; cancer; dosimetry; prosthetics; radioisotopes; thulium |
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Abstract |
Methods: The authors have assumed a theoretical Tm-170 cylindrical source encapsulated with stainless steel and typical dimensions taken from the currently available HDR Ir-192 brachytherapy sources. The dose-rate distribution was calculated for this source using the GEANT4 Monte Carlo (MC) code considering both photon and electron Tm-170 spectra. The AAPM TG-43 U1 brachytherapy dosimetry parameters were derived. To study general properties of Tm-170 encapsulated sources, spherical sources encapsulated with stainless steel and platinum were also studied. Moreover, the influence of small variations in the active core and capsule dimensions on the dosimetric characteristics was assessed. Treatment times required for a Tm-170 source were compared to those for Ir-192 and Yb-169 for the same contained activity. Results: Due to the energetic beta spectrum and the large electron yield, the bremsstrahlung contribution to the dose was of the same order of magnitude as from the emitted gammas and characteristic x rays. Moreover, the electron spectrum contribution to the dose was significant up to 4 mm from the source center compared to the photon contribution. The dose-rate constant Lambda of the cylindrical source was 1.23 cGy h(-1) U-1. The behavior of the radial dose function showed promise for applications in brachytherapy. Due to the electron spectrum, the anisotropy was large for r < 6 mm. Variations in manufacturing tolerances did not significantly influence the final dosimetry data when expressed in cGy h(-1) U-1. For typical capsule dimensions, maximum reference dose rates of about 0.2, 10, and 2 Gy min(-1) would then be obtained for Tm-170, Ir-192, and Yb-169, respectively, resulting in treatment times greater than those for HDR Ir-192 brachytherapy. Conclusions: The dosimetric characteristics of source designs exploiting the low photon energy of Tm-170 were studied for potential application in HDR-brachytherapy. Dose-rate distributions were obtained for cylindrical and simplified spherical Tm-170 source designs (stainless steel and platinum capsule materials) using MC calculations. Despite the high activity of Tm-170, calculated treatment times were much longer than for Ir-192. |
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Address |
[Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: fballest@uv.es |
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Amer Assoc Physicists Medicine Amer Inst Physics |
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Language |
English |
Summary Language |
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Series Volume |
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ISSN |
0094-2405 |
ISBN |
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Conference |
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Notes |
ISI:000276211200027 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
478 |
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Author |
Rivard, M.J.; Granero, D.; Perez-Calatayud, J.; Ballester, F. |
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Title |
Influence of photon energy spectra from brachytherapy sources on Monte Carlo simulations of kerma and dose rates in water and air |
Type |
Journal Article |
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Year |
2010 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
37 |
Issue |
2 |
Pages |
869-876 |
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Keywords |
biomedical materials; brachytherapy; dosimetry; iodine; iridium; Monte Carlo methods; palladium; radioisotopes |
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Abstract |
Methods: For Ir-192, I-125, and Pd-103, the authors considered from two to five published spectra. Spherical sources approximating common brachytherapy sources were assessed. Kerma and dose results from GEANT4, MCNP5, and PENELOPE-2008 were compared for water and air. The dosimetric influence of Ir-192, I-125, and Pd-103 spectral choice was determined. Results: For the spectra considered, there were no statistically significant differences between kerma or dose results based on Monte Carlo code choice when using the same spectrum. Water-kerma differences of about 2%, 2%, and 0.7% were observed due to spectrum choice for Ir-192, I-125, and Pd-103, respectively (independent of radial distance), when accounting for photon yield per Bq. Similar differences were observed for air-kerma rate. However, their ratio (as used in the dose-rate constant) did not significantly change when the various photon spectra were selected because the differences compensated each other when dividing dose rate by air-kerma strength. Conclusions: Given the standardization of radionuclide data available from the National Nuclear Data Center (NNDC) and the rigorous infrastructure for performing and maintaining the data set evaluations, NNDC spectra are suggested for brachytherapy simulations in medical physics applications. |
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Address |
[Rivard, Mark J.] Tufts Univ, Sch Med, Dept Radiat Oncol, Boston, MA 02111 USA, Email: mrivard@tuftsmedicalcenter.org |
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Amer Assoc Physicists Medicine Amer Inst Physics |
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English |
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ISSN |
0094-2405 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000274075600048 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
504 |
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Author |
Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J.A.; Gil, A.; Gonzalez-Diaz, D.; Koenig, W.; Traxler, M. |
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Title |
Performance of the Low-Jitter High-Gain/Bandwidth Front-End Electronics of the HADES tRPC Wall |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
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Volume |
57 |
Issue |
5 |
Pages |
2848-2856 |
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Keywords |
Charge to width algorithm; fast amplifying and digitizing electronics; front-end electronics; HADES; time of flight; timing RPC |
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Abstract |
A front-end electronics (FEE) chain for accurate time measurements has been developed for the new Resistive Plate Chamber (RPC)-based Time-of-Flight (TOF) wall of the High Acceptance Di-Electron Spectrometer (HADES). The wall covers an area of around 8 m(2) divided in 6 sectors. In total, 1122 4-gap timing RPC cells are read-out by 2244 time and charge sensitive channels. The FEE chain consists of 2 custom-made boards: a 4-channel Daughter BOard(DBO) and a 32-channel MotherBOard (MBO). The DBO uses a fast 2 GHz amplifier feeding a dual high-speed discriminator. The time and charge information are encoded, respectively, in the leading edge and the width of an LVDS signal. Each MBO houses up to 8 DBOs providing them regulated voltage supply, threshold values via DACs, test signals and, additionally, routing out a signal proportional to the channel multiplicity needed for a 1st level trigger decision. The MBO delivers LVDS signals to a multi-purpose Trigger Readout Board (TRB) for data acquisition. The FEE allows achieving a system resolution around 75 ps fulfilling comfortably the requirements of the HADES upgrade [1]. The commissioning of the whole RPC wall is finished and the 6 sectors are already mounted in their final position in the HADES spectrometer and ready to take data during the beam-times foreseen for 2010. |
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Address |
[Belver, Daniel; Cabanelas, P.; Castro, E.; Garzon, J. A.] Univ Santiago Compostela, LabCAF, Santiago De Compostela 15782, Spain, Email: daniel.belver@usc.es |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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Language |
English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
0018-9499 |
ISBN |
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Conference |
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Notes |
ISI:000283440400007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
349 |
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Author |
Bouhova-Thacker, E.; Kostyukhin, V.; Koffas, T.; Liebig, W.; Limper, M.; Piacquadio, G.N.; Prokofiev, K.; Weiser, C.; Wildauer, A. |
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Title |
Expected Performance of Vertex Reconstruction in the ATLAS Experiment at the LHC |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
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Volume |
57 |
Issue |
2 |
Pages |
760-767 |
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Keywords |
Data analysis; data reconstruction; high energy physics; pattern recognition; reconstruction algorithms; tracking; vertex detectors |
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Abstract |
In the harsh environment of the Large Hadron Collider at CERN (design luminosity of 10(34) cm(-2) s(-1)) efficient reconstruction of vertices is crucial for many physics analyses. Described in this paper is the expected performance of the vertex reconstruction used in the ATLAS experiment. The algorithms for the reconstruction of primary and secondary vertices as well as for finding photon conversions and vertex reconstruction in jets are described. The implementation of vertex algorithms which follows a very modular design based on object-oriented C++ is presented. A user-friendly concept allows event reconstruction and physics analyses to compare and optimize their choice among different vertex reconstruction strategies. The performance of implemented algorithms has been studied on a variety of Monte Carlo samples and results are presented. |
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Address |
[Bouhova-Thacker, Eva] Univ Lancaster, Lancaster LA1 4YB, England, Email: bouhova@mail.cern.ch |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9499 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000276679200006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
260 |
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Author |
Tetrault, M.A.; Oliver, J.F.; Bergeron, M.; Lecomte, R.; Fontaine, R. |
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Title |
Real Time Coincidence Detection Engine for High Count Rate Timestamp Based PET |
Type |
Journal Article |
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Year |
2010 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
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Volume |
57 |
Issue |
1 |
Pages |
117-124 |
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Keywords |
Coincidence detection; Positron Emission Tomography (PET) |
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Abstract |
Coincidence engines follow two main implementation flows: timestamp based systems and AND-gate based systems. The latter have been more widespread in recent years because of its lower cost and high efficiency. However, they are highly dependent on the selected electronic components, they have limited flexibility once assembled and they are customized to fit a specific scanner's geometry. Timestamp based systems are gathering more attention lately, especially with high channel count fully digital systems. These new systems must however cope with important singles count rates. One option is to record every detected event and postpone coincidence detection offline. For daily use systems, a real time engine is preferable because it dramatically reduces data volume and hence image preprocessing time and raw data management. This paper presents the timestamp based coincidence engine for the LabPET(TM), a small animal PET scanner with up to 4608 individual readout avalanche photodiode channels. The engine can handle up to 100 million single events per second and has extensive flexibility because it resides in programmable logic devices. It can be adapted for any detector geometry or channel count, can be ported to newer, faster programmable devices and can have extra modules added to take advantage of scanner-specific features. Finally, the user can select between full processing mode for imaging protocols and minimum processing mode to study different approaches for coincidence detection with offline software. |
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Address |
[Tetrault, M. -A.; Fontaine, R.] Univ Sherbrooke, Dept Elect & Comp Engn, Sherbrooke, PQ J1K 2R1, Canada, Email: Marc-Andre.Tetrault@USherbrooke.ca |
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Corporate Author |
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Thesis |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9499 |
ISBN |
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Area |
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Conference |
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Notes |
ISI:000274391000016 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
500 |
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