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Author  |
Piriz, G.H.; Gonzalez-Sprinberg, G.A.; Ballester, F.; Vijande, J. |
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Title |
Dosimetry of Large Field Valencia applicators for Cobalt-60-based brachytherapy |
Type |
Journal Article |
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Year |
2024 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
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Issue |
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Pages |
5pp |
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Keywords |
dosimetry; Monte Carlo; skin brachytherapy; Valencia applicators |
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Abstract |
BackgroundNon-melanoma skin cancer is one of the most common types of cancer and one of the main approaches is brachytherapy. For small lesions, the treatment of this cancer with brachytherapy can be done with two commercial applicators, one of these is the Large Field Valencia Applicators (LFVA).PurposeThe aim of this study is to test the capabilities of the LFVA to use clinically 60Co sources instead of the 192Ir ones. This study was designed for the same dwell positions and weights for both sources.MethodsThe Penelope Monte Carlo code was used to evaluate dose distribution in a water phantom when a 60Co source is considered. The LFVA design and the optimized dwell weights reported for the case of 192Ir are maintained with the only exception of the dwell weight of the central position, that was increased. 2D dose distributions, field flatness, symmetry and the leakage dose distribution around the applicator were calculated.ResultsWhen comparing the dose distributions of both sources, field flatness and symmetry remain unchanged. The only evident difference is an increase of the penumbra regions for all depths when using the 60Co source. Regarding leakage, the maximum dose within the air volume surrounding the applicator is in the order of 20% of the prescription dose for the 60Co source, but it decreases to less than 5% at about 1 cm distance.ConclusionsFlatness and symmetry remains unaltered as compared with 192Ir sources, while an increase in leakage has been observed. This proves the feasibility of using the LFVA in a larger range of clinical applications. |
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Address |
[Piriz, Gustavo H.; Gonzalez-Sprinberg, Gabriel A.] Univ Republica, Fac Sci, Med Phys Unit, Montevideo, Uruguay, Email: ghpiriz@gmail.com |
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Publisher |
Wiley |
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Language |
English |
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ISSN |
0094-2405 |
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Notes |
WOS:001187737100001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6011 |
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Author |
Perez-Calatayud, J.; Ballester, F.; Tedgren, C.; DeWerd, L.A.; Papagiannis, P.; Rivard, M.J.; Siebert, F.A.; Vijande, J. |
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Title |
GEC-ESTRO ACROP recommendations on calibration and traceability of HE HDR-PDR photon-emitting brachytherapy sources at the hospital level |
Type |
Journal Article |
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Year |
2022 |
Publication |
Radiotherapy and Oncology |
Abbreviated Journal |
Radiother. Oncol. |
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Volume |
176 |
Issue |
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Pages |
108-117 |
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Keywords |
Brachytherapy; High energy; Calibration; Dosimetry; HDR-PDR |
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Abstract |
The vast majority of radiotherapy departments in Europe using brachytherapy (BT) perform temporary implants of high-or pulsed-dose rate (HDR-PDR) sources with photon energies higher than 50 keV. Such techniques are successfully applied to diverse pathologies and clinical scenarios. These recommen-dations are the result of Working Package 21 (WP-21) initiated within the BRAchytherapy PHYsics Quality Assurance System (BRAPHYQS) GEC-ESTRO working group with a focus on HDR-PDR source cal-ibration. They provide guidance on the calibration of such sources, including practical aspects and issues not specifically accounted for in well-accepted societal recommendations, complementing the BRAPHYQS WP-18 Report dedicated to low energy BT photon emitting sources (seeds). The aim of this report is to provide a European-wide standard in HDR-PDR BT source calibration at the hospital level to maintain high quality patient treatments. |
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Address |
[Perez-Calatayud, Jose] La Fe Hosp, Radiotherapy Dept, Valencia, Spain, Email: javier.vijande@uv.es |
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Publisher |
Elsevier Ireland Ltd |
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English |
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ISSN |
0167-8140 |
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Notes |
WOS:000880438000006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5466 |
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Author |
Palomo, R.; Pujades, M.C.; Gimeno-Olmos, J.; Carmona, V.; Lliso, F.; Candela-Juan, C.; Vijande, J.; Ballester, F.; Perez-Calatayud, J. |
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Title |
Evaluation of lens absorbed dose with Cone Beam IGRT procedures |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
35 |
Issue |
4 |
Pages |
N33-N41 |
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Keywords |
IGRT; CBCT; lens absorbed dose; TLD |
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Abstract |
The purpose of this work is to evaluate the absorbed dose to the eye lenses due to the cone beam computed tomography (CBCT) system used to accurately position the patient during head-and-neck image guided procedures. The on-board imaging (OBI) systems (v. 1.5) of Clinac iX and TrueBeam (Varian) accelerators were used to evaluate the imparted dose to the eye lenses and some additional points of the head. All CBCT scans were acquired with the Standard-Dose Head protocol from Varian. Doses were measured using thermoluminescence dosimeters (TLDs) placed in an anthropomorphic phantom. TLDs were calibrated at the beam quality used to reduce their energy dependence. Average dose to the lens due to the OBI systems of the Clinac iX and the TrueBeam were 0.71 +/- 0.07 mGy/CBCT and 0.70 +/- 0.08 mGy/CBCT, respectively. The extra absorbed dose received by the eye lenses due to one CBCT acquisition with the studied protocol is far below the 500 mGy threshold established by ICRP for cataract formation (ICRP 2011 Statement on Tissue Reactions). However, the incremental effect of several CBCT acquisitions during the whole treatment should be taken into account. |
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Address |
[Palomo, R.; Gimeno-Olmos, J.; Carmona, V.; Lliso, F.; Candela-Juan, C.; Perez-Calatayud, J.] La Fe Univ, Dept Radiotherapy, Phys Sect, E-46026 Valencia, Spain, Email: mpuclau@gmail.com |
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Publisher |
Iop Publishing Ltd |
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English |
Summary Language |
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Original Title |
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Series Volume |
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Edition |
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ISSN |
0952-4746 |
ISBN |
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Notes |
WOS:000366388500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2494 |
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Author |
Oliver-Canamas, L.; Vijande, J.; Candela-Juan, C.; Gimeno-Olmos, J.; Pujades-Claumarchirant, M.C.; Rovira-Escutia, J.J.; Ballester, F.; Perez-Calatayud, J. |
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Title |
A User-Friendly System for Mailed Dosimetric Audits of Ir-192 or Co-60 HDR Brachytherapy Sources |
Type |
Journal Article |
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Year |
2023 |
Publication |
Cancers |
Abbreviated Journal |
Cancers |
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Volume |
15 |
Issue |
9 |
Pages |
2484 - 14pp |
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Keywords |
high dose rate brachytherapy; dosimetric audit; error detection; phantom |
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Abstract |
Nowadays, the options available to perform external dosimetric audits of the high dose rate (HDR) brachytherapy treatment process are limited. In this work, we present a methodology that allows for performing dosimetric audits in this field. A phantom was designed and manufactured for this purpose. The criteria for its design, together with the in-house measurements for its characterization, are presented. The result is a user-friendly system that can be mailed to perform dosimetric audits in HDR brachytherapy on-site for systems using either Iridium-192 (Ir-192) or Cobalt-60 (Co-60) sources. Objectives: The main goal of this work is to design and characterize a user-friendly methodology to perform mailed dosimetric audits in high dose rate (HDR) brachytherapy for systems using either Iridium-192 (Ir-192) or Cobalt-60 (Co-60) sources. Methods: A solid phantom was designed and manufactured with four catheters and a central slot to place one dosimeter. Irradiations with an Elekta MicroSelectron V2 for Ir-192, and with a BEBIG Multisource for Co-60 were performed for its characterization. For the dose measurements, nanoDots, a type of optically stimulated luminescent dosimeters (OSLDs), were characterized. Monte Carlo (MC) simulations were performed to evaluate the scatter conditions of the irradiation set-up and to study differences in the photon spectra of different Ir-192 sources (Microselectron V2, Flexisource, BEBIG Ir2.A85-2 and Varisource VS2000) reaching the dosimeter in the irradiation set-up. Results: MC simulations indicate that the surface material on which the phantom is supported during the irradiations does not affect the absorbed dose in the nanoDot. Generally, differences below 5% were found in the photon spectra reaching the detector when comparing the Microselectron V2, the Flexisource and the BEBIG models. However, differences up to 20% are observed between the V2 and the Varisource VS2000 models. The calibration coefficients and the uncertainty in the dose measurement were evaluated. Conclusions: The system described here is able to perform dosimetric audits in HDR brachytherapy for systems using either Ir-192 or Co-60 sources. No significant differences are observed between the photon spectra reaching the detector for the MicroSelectron V2, the Flexisource and the BEBIG Ir-192 sources. For the Varisource VS2000, a higher uncertainty is considered in the dose measurement to allow for the nanoDot response. |
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Address |
[Oliver-Canamas, Laura] Serv Radiofis & Proteccio Radiol, Consorci Hospitalari Prov Castello CHPC, Castellon de La Plana 12002, Spain, Email: laura.oliver.canas@gmail.com |
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Publisher |
Mdpi |
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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Notes |
WOS:000987247100001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
5542 |
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Author |
Oliver, S.; Vijande, J.; Tejedor-Aguilar, N.; Miro, R.; Rovira-Escutia, J.J.; Ballester, F.; Juste, B.; Carmona, V.; Felici, G.; Verdu, G.; Sanchis, E.; Conde, A.; Perez-Calatayud, J. |
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Title |
Monte Carlo flattening filter design to high energy intraoperative electron beam homogenization |
Type |
Journal Article |
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Year |
2023 |
Publication |
Radiation Physics and Chemistry |
Abbreviated Journal |
Radiat. Phys. Chem. |
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Volume |
212 |
Issue |
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Pages |
111102 - 6pp |
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Keywords |
Intraoperative radiotherapy; Electron portable LinAc; Flattening filter; Dosimetry; Monte Carlo |
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Abstract |
Intraoperative radiotherapy using mobile linear accelerators is used for a wide variety of malignancies. However, when large fields are used in combination with high energies, a deterioration of the flatness dose profile is measured with respect to smaller fields and lower energies. Indeed, for the LIAC HWL of Sordina, this deterioration is observed for the 12 MeV beam combined with 10 cm (or larger) diameter applicator. Aimed to solve this problem, a flattening filter has been designed and validated evaluating the feasibility of its usage at the upper part of the applicator. The design of the filter was based on Monte Carlo simulations because of its accuracy in modeling components of clinical devices, among other purposes. The LIAC 10 cm diameter applicator was modeled and simulated independently by two different research groups using two different MC codes, reproducing the heterogeneity of the 12 MeV energy beam. Then, an iterative process of filter design was carried out. Finally, the MC designed conical filter with the optimal size and height to obtain the desired flattened beam was built in-house using a 3D printer. During the experimental validation of the applicator-filter, percentage depth dose, beam profiles, absolute and peripheral dose measurements were performed to demonstrate the effectiveness of the filter addition in the applicator. These measurements conclude that the beam has been flattened, from 5.9% with the standard configuration to 1.6% for the configuration with the filter, without significant increase of the peripheral dose. Consequently, the new filter-applicator LIAC configuration can be used also in a conventional surgery room. A reduction of 16% of the output dose and a reduction of 1.1 mm in the D50 of the percentage depth dose was measured with respect to the original configuration. This work is a proof-of-concept that demonstrates that it is possible to add a filter able to flatten the beam delivered by the Sordina LIAC HWL. Future studies will focus on more refined technical solutions fully compatible with the integrity of the applicator, including its sterilization, to be safely introduced in the clinical practice. |
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Address |
[Oliver, S.; Miro, R.; Juste, B.; Verdu, G.] Univ Polite cn Vale ncia, Inst Segur Ind Radiofis & Medioambiental ISIRYM, Cami Vera S-N, Valencia 46022, Spain, Email: gverdu@iqn.upv.es |
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Publisher |
Pergamon-Elsevier Science Ltd |
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Language |
English |
Summary Language |
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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 |
0969-806x |
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Notes |
WOS:001026194900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5578 |
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