| Records |
| Author |
Granero, D.; Perez-Calatayud, J.; Vijande, J.; Ballester, F.; Rivard, M.J. |
| Title |
Limitations of the TG-43 formalism for skin high-dose-rate brachytherapy dose calculations |
Type |
Journal Article |
| Year |
2014 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
41 |
Issue |
2 |
Pages |
021703 - 8pp |
| Keywords |
HDR; brachytherapy; skin; Monte Carlo; Geant4; Co-60; Ir-192; Yb-169 |
| Abstract |
Purpose: In skin high-dose-rate (HDR) brachytherapy, sources are located outside, in contact with, or implanted at some depth below the skin surface. Most treatment planning systems use the TG-43 formalism, which is based on single-source dose superposition within an infinite water medium without accounting for the true geometry in which conditions for scattered radiation are altered by the presence of air. The purpose of this study is to evaluate the dosimetric limitations of the TG-43 formalism in HDR skin brachytherapy and the potential clinical impact. Methods: Dose rate distributions of typical configurations used in skin brachytherapy were obtained: a 5 cm x 5 cm superficial mould; a source inside a catheter located at the skin surface with and without backscatter bolus; and a typical interstitial implant consisting of an HDR source in a catheter located at a depth of 0.5 cm. Commercially available HDR Co-60 and Ir-192 sources and a hypothetical Yb-169 source were considered. The Geant4Monte Carlo radiation transport code was used to estimate dose rate distributions for the configurations considered. These results were then compared to those obtained with the TG-43 dose calculation formalism. In particular, the influence of adding bolus material over the implant was studied. Results: For a 5 cm x 5 cm Ir-192 superficial mould and 0.5 cm prescription depth, dose differences in comparison to the TG-43 method were about -3%. When the source was positioned at the skin surface, dose differences were smaller than -1% for Co-60 and Ir-192, yet -3% for Yb-169. For the interstitial implant, dose differences at the skin surface were -7% for Co-60, -0.6% for Ir-192, and -2.5% for Yb-169. Conclusions: This study indicates the following: (i) for the superficial mould, no bolus is needed; (ii) when the source is in contact with the skin surface, no bolus is needed for either Co-60 and Ir-192. For lower energy radionuclides like Yb-169, bolus may be needed; and (iii) for the interstitial case, at least a 0.1 cm bolus is advised for Co-60 to avoid underdosing superficial target layers. For Ir-192 and Yb-169, no bolus is needed. For those cases where no bolus is needed, its use might be detrimental as the lack of radiation scatter may be beneficial to the patient, although the 2% tolerance for dose calculation accuracy recommended in the AAPM TG-56 report is not fulfilled. |
| Address |
[Granero, Domingo] Hosp Gen Univ, ERESA, Dept Radiat Phys, Valencia 46014, Spain, Email: dgranero@eresa.com |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
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 |
|
Edition |
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| ISSN |
0094-2405 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000331213300006 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1704 |
| Permanent link to this record |
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| Author |
Granero, D.; Vijande, J.; Ballester, F.; Rivard, M.J. |
| Title |
Dosimetry revisited for the HDR Ir-192 brachytherapy source model mHDR-v2 |
Type |
Journal Article |
| Year |
2011 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
38 |
Issue |
1 |
Pages |
487-494 |
| Keywords |
Ir-192; brachytherapy; dosimetry; TG-43; PSS model; MCNP5; PENELOPE2008; GEANT4 |
| 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. |
| Address |
[Granero, Domingo] Hosp Gen Univ, Dept Radiat Phys, ERESA, E-46014 Valencia, Spain, Email: dgranero@eresa.com |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
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 |
0094-2405 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000285769800050 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
557 |
| Permanent link to this record |
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| Author |
Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Tain, J.L.; Algora, A.; Berthoumieux, E.; Colonna, N.; Domingo-Pardo, C.; Gonzalez-Romero, E.; Heil, M.; Jordan, D.; Kappeler, F.; Lampoudis, C.; Martinez, T.; Massimi, C.; Plag, R. |
| Title |
Monte Carlo simulation of the n_TOF Total Absorption Calorimeter |
Type |
Journal Article |
| Year |
2012 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
671 |
Issue |
|
Pages |
108-117 |
| Keywords |
Monte Carlo simulation; Geant4; Neutron cross-sections; Time-of-flight; Neutron capture |
| Abstract |
The n_TOF Total Absorption Calorimeter (TAC) is a 4 pi BaF2 segmented detector used at CERN for measuring neutron capture cross-sections of importance for the design of advanced nuclear reactors. This work presents the simulation code that has been developed in GEANT4 for the accurate determination of the detection efficiency of the TAC for neutron capture events. The code allows to calculate the efficiency of the TAC for every neutron capture state, as a function of energy, crystal multiplicity, and counting rate. The code includes all instrumental effects such as the single crystal detection threshold and energy resolution, finite size of the coincidence time window, and signal pile-up. The results from the simulation have been validated with experimental data for a large set of electromagnetic de-excitation patterns: beta-decay of well known calibration sources, neutron capture reactions in light nuclei with well known level schemes like Ti-nat, reference samples used in (n,gamma) measurements like Au-197 and experimental data from an actinide sample like Pu-240. The systematic uncertainty in the determination of the detection efficiency has been estimated for all the cases. As a representative example, the accuracy reached for the case of Au-197(n,gamma) ranges between 0.5% and 2%, depending on the experimental and analysis conditions. Such a value matches the high accuracy required for the nuclear cross-section data needed in advanced reactor design. |
| Address |
[Guerrero, C.; Cano-Ott, D.; Mendoza, E.; Gonzalez-Romero, E.; Martinez, T.] CIEMAT, Ctr Invest Energet Medioambientales & Tecnol, E-28040 Madrid, Spain, Email: carlos.guerrero@cern.ch |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
|
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
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Edition |
|
| ISSN |
0168-9002 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000301474600013 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
973 |
| Permanent link to this record |
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| Author |
Hornillos, M.B.G.; Gorlychev, V.; Caballero, R.; Cortes, G.; Poch, A.; Pretel, C.; Calvino, F.; Tain, J.L.; Algora, A.; Agramunt, J.; Cano-Ott, D.; Martinez, T.; Mendoza, E.; Rissanen, J.; Aysto, J.; Jokinen, A.; Eronen, T.; Moore, I.; Penttila, H. |
| Title |
Monte Carlo Simulations for the Study of a Moderated Neutron Detector |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
| Volume |
59 |
Issue |
2 |
Pages |
1573-1576 |
| Keywords |
Monte Carlo simulations; GEANT4; MCNPX; Beta delayed neutron emission; Neutron detector |
| Abstract |
This work presents the Monte Carlo simulations performed with the MCNPX and GEANT4 codes for the design of a BEta deLayEd Neutron detector, BELEN-20. This detector will be used for the study of beta delayed neutron emission and consists of a block of polyethylene with dimensions 90 x 90 x 80 cm(3) and 20 cylindrical (3)He gas counters. The results of these simulations have been validated experimentally with a (252)Cf source in the laboratory at UPC, Barcelona. Also the first experiment with this detector has been carried out in November 2009 in JYFL, Finland. In this experiment the neutron emission probability after beta decay of the fission products (88)Br, (94,95)Rb, and (138)I has been measured; this data is still under analysis. Simulations with MCNPX and GEANT4 have been performed in order to obtain the efficiency of the BELEN-20 detector for each of the above nuclei using the neutron energy distribution corresponding to each nucleus. |
| Address |
[Hornillos, MBG; Gorlychev, V; Caballero, R; Cortes, G; Poch, A; Pretel, C; Calvino, F] Univ Politecn Cataluna, Seccio Engn Nucl, E-08028 Barcelona, Spain, Email: belen.gomez@upc.edu |
| Corporate Author |
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Thesis |
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| Publisher |
Korean Physical Soc |
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 |
|
Series Issue |
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Edition |
|
| ISSN |
0374-4884 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000294080700028 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
733 |
| Permanent link to this record |
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| Author |
Jaworski, G.; Palacz, M.; Nyberg, J.; de Angelis, G.; de France, G.; Di Nitto, A.; Egea, F.J.; Erduran, M.N.; Erturk, S.; Farnea, E.; Gadea, A.; Gonzalez, V.; Gottardo, A.; Huyuk, T.; Kownacki, J.; Pipidis, A.; Roeder, B.; Soderstrom, P.A.; Sanchis, E.; Tarnowski, R.; Triossi, A.; Wadsworth, R.; Valiente-Dobon, J.J. |
| Title |
Monte Carlo simulation of a single detector unit for the neutron detector array NEDA |
Type |
Journal Article |
| Year |
2012 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
673 |
Issue |
|
Pages |
64-72 |
| Keywords |
Monte Carlo simulation; BC501; BC501A; BC537; Liquid scintillator; Neutron detector; Geant4; NEDA |
| Abstract |
A study of the dimensions and performance of a single detector of the future neutron detector array NEDA was performed by means of Monte Carlo simulations, using GEANT4. Two different liquid scintillators were evaluated: the hydrogen based BC501A and the deuterated BC537. The efficiency and the probability that one neutron will trigger a signal in more than one detector were investigated as a function of the detector size. The simulations were validated comparing the results to experimental measurements performed with two existing neutron detectors, with different geometries, based on the liquid scintillator BC501. |
| Address |
[Jaworski, G.; Palacz, M.; Kownacki, J.; Tarnowski, R.] Univ Warsaw, Heavy Ion Lab, PL-02093 Warsaw, Poland, Email: palacz@slcj.uw.edu.pl |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0168-9002 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000301813500009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
944 |
| Permanent link to this record |
