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Author |
Granero, D.; Vijande, J.; Ballester, F.; Rivard, M.J. |
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Title  |
Dosimetry revisited for the HDR Ir-192 brachytherapy source model mHDR-v2 |
Type |
Journal Article |
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Year |
2011 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
38 |
Issue |
1 |
Pages |
487-494 |
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Keywords |
Ir-192; brachytherapy; dosimetry; TG-43; PSS model; MCNP5; PENELOPE2008; GEANT4 |
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Abstract |
Purpose: Recently, the manufacturer of the HDR Ir-192 mHDR-v2 brachytherapy source reported small design changes (referred to herein as mHDR-v2r) that are within the manufacturing tolerances but may alter the existing dosimetric data for this source. This study aimed to (1) check whether these changes affect the existing dosimetric data published for this source; (2) obtain new dosimetric data in close proximity to the source, including the contributions from 192Ir electrons and considering the absence of electronic equilibrium; and (3) obtain scatter dose components for collapsed cone treatment planning system implementation. Methods: Three different Monte Carlo (MC) radiation transport codes were used: MCNP5, PENELOPE2008, and GEANT4. The source was centrally positioned in a 40 cm radius water phantom. Absorbed dose and collision kerma were obtained using 0.1 mm (0.5 mm) thick voxels to provide high-resolution dosimetry near (far from) the source. Dose-rate distributions obtained with the three MC codes were compared. Results: Simulations of mHDR-v2 and mHDR-v2r designs performed with three radiation transport codes showed agreement typically within 0.2% for r >= 0.25 cm. Dosimetric contributions from source electrons were significant for r<0.25 cm. The dose-rate constant and radial dose function were similar to those from previous MC studies of the mHDR-v2 design. The 2D anisotropy function also coincided with that of the mHDR-v2 design for r >= 0.25 cm. Detailed results of dose distributions and scatter components are presented for the modified source design. Conclusions: Comparison of these results to prior MC studies showed agreement typically within 0.5% for r >= 0.25 cm. If dosimetric data for r<0.25 cm are not needed, dosimetric results from the prior MC studies will be adequate. c 2011 American Association of Physicists in Medicine. |
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Address |
[Granero, Domingo] Hosp Gen Univ, Dept Radiat Phys, ERESA, E-46014 Valencia, Spain, Email: dgranero@eresa.com |
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Amer Assoc Physicists Medicine Amer Inst Physics |
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English |
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ISSN |
0094-2405 |
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Notes |
ISI:000285769800050 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
557 |
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Author |
Fernandez-Carames, T.; Valcarce, A.; Vijande, J. |
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Title |
Doubly charmed exotic mesons: A gift of nature? |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
699 |
Issue |
4 |
Pages |
291-295 |
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Keywords |
Exotic mesons; Quark model; Multiquark states |
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Abstract |
We study doubly charmed exotic states by solving the scattering problem of two D mesons. Our results point to the existence of a stable isoscalar doubly charmed meson with quantum numbers (I)J(P) = (0)1(+). We perform a thorough comparison to the results obtained within the hyperspherical harmonic formalism. Such exotic states could be measured at LHC and RHIC. Their experimental observation would, for the first time, confirm the contribution of multiquark structures to hadron spectroscopy. |
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Address |
[Carames, T. F.; Valcarce, A.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: valcarce@usal.es |
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Publisher |
Elsevier Science Bv |
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English |
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ISSN |
0370-2693 |
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Notes |
ISI:000291073200016 |
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no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
634 |
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Author |
Garcilazo, H.; Valcarce, A.; Vijande, J. |
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Title |
Doubly heavy baryon spectra guided by lattice QCD |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
94 |
Issue |
7 |
Pages |
074003 - 8pp |
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Abstract |
This paper provides results for the ground state and excited spectra of three-flavored doubly heavy baryons, bcn and bcs. We take advantage of the spin-independent interaction recently obtained to reconcile the lattice SU(3) QCD static potential and the results of nonperturbative lattice QCD for the triply heavy baryon spectra. We show that the spin-dependent potential might be constrained on the basis of nonperturbative lattice QCD results for the spin splittings of three-flavored doubly heavy baryons. Our results may also represent a challenge for future lattice QCD work, because a smaller lattice error could help in distinguishing between different prescriptions for the spin-dependent part of the interaction. Thus, by comparing with the reported baryon spectra obtained with parameters estimated from lattice QCD, one can challenge the precision of lattice calculations. The present work supports a coherent description of singly, doubly and triply heavy baryons with the same Cornell-like interacting potential. The possible experimental measurement of these states at LHCb is an incentive for this study. |
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Address |
[Garcilazo, H.] Inst Politecn Nacl, Escuela Super Fis & Matemat, Edificio 9, Mexico City 07738, DF, Mexico, Email: humberto@esfm.ipn.mx; |
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Amer Physical Soc |
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English |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Notes |
WOS:000384473600003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2821 |
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Author |
Richard, J.M.; Valcarce, A.; Vijande, J. |
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Title |
Effect of relativistic kinematics on the stability of multiquarks |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
103 |
Issue |
5 |
Pages |
054020 - 8pp |
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Abstract |
We discuss whether the bound nature of multiquark states in quark models could benefit from relativistic effects on the kinetic energy operator. For mesons and baryons, relativistic corrections to the kinetic energy lead to lower energies, and thus call for a retuning of the parameters of the model. For multiquark states, as well as their respective thresholds, a comparison is made of the results obtained with nonrelativistic and relativistic kinetic energy. It is found that the binding energy is lower in the relativistic case. In particular, QQ (q) over bar(q) over bar tetraquarks with double heavy flavor become stable for a larger ratio of the heavy to light quark masses; the all-heavy tetraquarks QQ (Q) over bar(Q) over bar that are not stable in standard nonrelativistic quark models remain unstable when a relativistic form of kinetic energy is adopted. |
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Address |
[Richard, Jean-Marc] Univ Lyon, Inst Phys Infinis Lyon 2, IN2P3 CNRS UCBL, 4 Rue Enrico Fermi, F-69622 Villeurbanne, France, Email: j-m.richard@ipnl.in2p3.fr; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Editor |
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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 |
2470-0010 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000648531300004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4838 |
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Author |
Assam, I.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Poppe, B.; Siebert, F.A. |
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Title |
Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for I-125 prostate implants |
Type |
Journal Article |
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Year |
2022 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
49 |
Issue |
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Pages |
6195-6208 |
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Keywords |
metallic artifact reduction; Monte Carlo dosimetry; post-implant CT; prostate brachytherapy; tissue assignment schemes; voxelized virtual patient model |
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Abstract |
Purpose Monte Carlo (MC) simulation studies, aimed at evaluating the magnitude of tissue heterogeneity in I-125 prostate permanent seed implant brachytherapy (BT), customarily use clinical post-implant CT images to generate a virtual representation of a realistic patient model (virtual patient model). Metallic artifact reduction (MAR) techniques and tissue assignment schemes (TAS) are implemented on the post-implant CT images to mollify metallic artifacts due to BT seeds and to assign tissue types to the voxels corresponding to the bright seed spots and streaking artifacts, respectively. The objective of this study is to assess the combined influence of MAR and TAS on MC absorbed dose calculations in post-implant CT-based phantoms. The virtual patient models used for I-125 prostate implant MC absorbed dose calculations in this study are derived from the CT images of an external radiotherapy prostate patient without BT seeds and prostatic calcifications, thus averting the need to implement MAR and TAS. Methods The geometry of the IsoSeed I25.S17plus source is validated by comparing the MC calculated results of the TG-43 parameters for the line source approximation with the TG-43U1S2 consensus data. Four MC absorbed dose calculations are performed in two virtual patient models using the egs_brachy MC code: (1) TG-43-based D-w,w-TG(43), (2) D-w,D-w-MBDC that accounts for interseed scattering and attenuation (ISA), (3) D-m,D-m that examines ISA and tissue heterogeneity by scoring absorbed dose in tissue, and (4) D-w,D-m that unlike D-m,D-m scores absorbed dose in water. The MC absorbed doses (1) and (2) are simulated in a TG-43 patient phantom derived by assigning the densities of every voxel to 1.00 g cm(-3) (water), whereas MC absorbed doses (3) and (4) are scored in the TG-186 patient phantom generated by mapping the mass density of each voxel to tissue according to a CT calibration curve. The MC absorbed doses calculated in this study are compared with VariSeed v8.0 calculated absorbed doses. To evaluate the dosimetric effect of MAR and TAS, the MC absorbed doses of this work (independent of MAR and TAS) are compared to the MC absorbed doses of different I-125 source models from previous studies that were calculated with different MC codes using post-implant CT-based phantoms generated by implementing MAR and TAS on post-implant CT images. Results The very good agreement of TG-43 parameters of this study and the published consensus data within 3% validates the geometry of the IsoSeed I25.S17plus source. For the clinical studies, the TG-43-based calculations show a D-90 overestimation of more than 4% compared to the more realistic MC methods due to ISA and tissue composition. The results of this work generally show few discrepancies with the post-implant CT-based dosimetry studies with respect to the D-90 absorbed dose metric parameter. These discrepancies are mainly Type B uncertainties due to the different I-125 source models and MC codes. Conclusions The implementation of MAR and TAS on post-implant CT images have no dosimetric effect on the I-125 prostate MC absorbed dose calculation in post-implant CT-based phantoms. |
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Address |
[Assam, Isong; Siebert, Frank-Andre] UKSH, Clin Radiotherapy Radiooncol, Campus Kiel, Kiel, Germany, Email: Isong.Assam@uksh.de |
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Thesis |
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Publisher |
Wiley |
Place of Publication |
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Language |
English |
Summary Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0094-2405 |
ISBN |
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Conference |
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Notes |
WOS:000835807200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5321 |
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