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Author  |
Quintero-Quintero, A.; Patiño-Camargo, G.; Soriano, A.; Palma, J.D.; Vilar-Palop, J.; Pujades, M.C.; Llorca-Domaica, N.; Ballester, F.; Vijande, J.; Candela-Juan, C. |
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Title |
Calibration of a thermoluminescent dosimeter worn over lead aprons in fluoroscopy guided procedures |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
38 |
Issue |
2 |
Pages |
549-563 |
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Keywords |
backscatter correction factor; TLD; lead apron; fluoroscopy; eye lens dose |
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Abstract |
Fluoroscopy guided interventional procedures provide remarkable benefits to patients. However, medical staff working near the scattered radiation field may be exposed to high cumulative equivalent doses, thus requiring shielding devices such as lead aprons and thyroid collars. In this situation, it remains an acceptable practice to derive equivalent doses to the eye lenses or other unprotected soft tissues with a dosimeter placed above these protective devices. Nevertheless, the radiation backscattered by the lead shield differs from that generated during dosimeter calibration with a water phantom. In this study, a passive personal thermoluminescent dosimeter (TLD) was modelled by means of the Monte Carlo (MC) code Penelope. The results obtained were validated against measurements performed in reference conditions in a secondary standard dosimetry laboratory. Next, the MC model was used to evaluate the backscatter correction factor needed for the case where the dosimeter is worn over a lead shield to estimate the personal equivalent dose H-p(0.07) to unprotected soft tissues. For this purpose, the TLD was irradiated over a water slab phantom with a photon beam representative of the result of a fluoroscopy beam scattered by a patient. Incident beam angles of 0 degrees and 60 degrees, and lead thicknesses between the TLD and phantom of 0.25 and 0.5 mm Pb were considered. A backscatter correction factor of 1.23 (independent of lead thickness) was calculated comparing the results with those faced in reference conditions (i.e., without lead shield and with an angular incidence of 0 degrees). The corrected dose algorithm was validated in laboratory conditions with dosi-meters irradiated over a thyroid collar and angular incidences of 0 degrees, 40 degrees and 60 degrees, as well as with dosimeters worn by interventional radiologists and cardiologists. The corrected dose algorithm provides a better approach to estimate the equivalent dose to unprotected soft tissues such as eye lenses. Dosimeters that are not shielded from backscatter radiation might underestimate personal equivalent doses when worn over a lead apron and, therefore, should be specifically characterized for this purpose. |
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Address |
[Quintero-Quintero, A.; Patino-Camargo, G.] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Valencia, Spain, Email: ccanjuan@gmail.com |
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Publisher |
Iop Publishing Ltd |
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English |
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Series Volume |
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Edition |
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ISSN |
0952-4746 |
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Conference |
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Notes |
WOS:000428913900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3552 |
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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 |
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ISSN |
0952-4746 |
ISBN |
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Conference |
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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 |
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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 |
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Language |
English |
Summary Language |
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Original Title |
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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 |
Ibanez-Rosello, B.; Bautista-Ballesteros, J.A.; Candela-Juan, C.; Villaescusa, J.I.; Ballester, F.; Vijande, J.; Perez-Calatayud, J. |
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Title |
Evaluation of the shielding in a treatment room with an electronic brachytherapy unit |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
37 |
Issue |
2 |
Pages |
N5-N12 |
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Keywords |
Esteya; electronic brachytherapy; shielding; radiation protection |
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Abstract |
Esteya (R) (Elekta Brachytherapy, Veenendaal, The Netherlands) is an electronic brachytherapy (eBT) system based on a 69.5 kVp x-ray source and a set of collimators of 1 to 3 cm in diameter, used for treating non-melanoma skin cancer lesions. This study aims to estimate room shielding requirements for this unit. The non-primary (scattered and leakage) ambient dose equivalent rates were measured with a Berthold LB-133 monitor (Berthold Technologies, Bad Wildbad, Germany). The latter ranges from 17 mSv h(-1) at 0.25 m distance from the x-ray source to 0.1 mSv h(-1) at 2.5 m. The necessary room shielding was then estimated following US and some European guidelines. The room shielding for all barriers considered was below 2 mmPb. The dose to a companion who, exceptionally, would stay with the patient during all treatment was estimated to be below 1 mSv if a leaded apron is used. In conclusion, Esteya shielding requirements are minimal. |
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Address |
[Ibanez-Rosello, Blanca; Ignacio Villaescusa, Juan] La Fe Univ, Radioprotect Dept, E-46026 Valencia, Spain, Email: blanca.ibanez.rosello@gmail.com |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
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 |
0952-4746 |
ISBN |
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Notes |
WOS:000413778600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
3344 |
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Author |
Granero, D.; Candela-Juan, C.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Jacob, D.; Mourtada, F. |
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Title |
Technical Note: Dosimetry of Leipzig and Valencia applicators without the plastic cap |
Type |
Journal Article |
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Year |
2016 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
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Volume |
43 |
Issue |
5 |
Pages |
2087 - 4pp |
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Keywords |
Leipzig applicators; Valencia applicators; skin brachytherapy; Monte Carlo; dosimetry |
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Abstract |
Purpose: High dose rate (HDR) brachytherapy for treatment of small skin lesions using the Leipzig and Valencia applicators is a widely used technique. These applicators are equipped with an attachable plastic cap to be placed during fraction delivery to ensure electronic equilibrium and to prevent secondary electrons from reaching the skin surface. The purpose of this study is to report on the dosimetric impact of the cap being absent during HDR fraction delivery, which has not been explored previously in the literature. Methods: GEANT4 Monte Carlo simulations (version 10.0) have been performed for the Leipzig and Valencia applicators with and without the plastic cap. In order to validate the Monte Carlo simulations, experimental measurements using radiochromic films have been done. Results: Dose absorbed within 1 mm of the skin surface increases by a factor of 1500% for the Leipzig applicators and of 180% for the Valencia applicators. Deeper than 1 mm, the overdosage flattens up to a 10% increase. Conclusions: Differences of treating with or without the plastic cap are significant. Users must check always that the plastic cap is in place before any treatment in order to avoid overdosage of the skin. Prior to skin HDR fraction delivery, the timeout checklist should include verification of the cap placement. (C) 2016 American Association of Physicists in Medicine. |
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Address |
[Granero, D.] Hosp Gen Univ, Dept Radiat Phys, ERESA, Valencia 46014, Spain, Email: dgranero@eresa.com |
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Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
0094-2405 |
ISBN |
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Conference |
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Notes |
WOS:000378924200010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2753 |
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