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Author Gimenez-Alventosa, V.; Gimenez, V.; Ballester, F.; Vijande, J.; Andreo, P.
Title Correction factors for ionization chamber measurements with the 'Valencia' and 'large field Valencia' brachytherapy applicators Type Journal Article
Year 2018 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume 63 Issue 12 Pages 125004 - 10pp
Keywords skin applicator; Valencia applicator; large field Valencia applicator; HDR brachytherap; brachytherapy dosimetry; Monte Carlo
Abstract Treatment of small skin lesions using HDR brachytherapy applicators is a widely used technique. The shielded applicators currently available in clinical practice are based on a tungsten-alloy cup that collimates the source-emitted radiation into a small region, hence protecting nearby tissues. The goal of this manuscript is to evaluate the correction factors required for dose measurements with a plane-parallel ionization chamber typically used in clinical brachytherapy for the 'Valencia' and 'large field Valencia' shielded applicators. Monte Carlo simulations have been performed using the PENELOPE-2014 system to determine the absorbed dose deposited in a water phantom and in the chamber active volume with a Type A uncertainty of the order of 0.1%. The average energies of the photon spectra arriving at the surface of the water phantom differ by approximately 10%, being 384 keV for the 'Valencia' and 343 keV for the 'large field Valencia'. The ionization chamber correction factors have been obtained for both applicators using three methods, their values depending on the applicator being considered. Using a depth-independent global chamber perturbation correction factor and no shift of the effective point of measurement yields depth-dose differences of up to 1% for the 'Valencia' applicator. Calculations using a depth-dependent global perturbation factor, or a shift of the effective point of measurement combined with a constant partial perturbation factor, result in differences of about 0.1% for both applicators. The results emphasize the relevance of carrying out detailed Monte Carlo studies for each shielded brachytherapy applicator and ionization chamber.
Address [Gimenez-Alventosa, V.] Univ Politecn Valencia, CSIC, Ctr Mixto, Inst Instrumentac Imagen Mol I3M, E-46022 Valencia, Spain, Email: Javier.vijande@uv.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000434682500004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3609
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Author Muñoz, E.; Barrio, J.; Etxebeste, A.; Ortega, P.G.; Lacasta, C.; Oliver, J.F.; Solaz, C.; Llosa, G.
Title Performance evaluation of MACACO: a multilayer Compton camera Type Journal Article
Year 2017 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume 62 Issue 18 Pages 7321-7341
Keywords Compton imaging; Compton camera; continuous LaBr3 crystal; silicon photomultiplier; hadron therapy
Abstract Compton imaging devices have been proposed and studied for a wide range of applications. We have developed a Compton camera prototype which can be operated with two or three detector layers based on monolithic lanthanum bromide (LaBr3) crystals coupled to silicon photomultipliers (SiPMs), to be used for proton range verification in hadron therapy. In this work, we present the results obtained with our prototype in laboratory tests with radioactive sources and in simulation studies. Images of a Na-22 and an Y-88 radioactive sources have been successfully reconstructed. The full width half maximum of the reconstructed images is below 4 mm for a Na-22 source at a distance of 5 cm.
Address [Munoz, Enrique; Barrio, John; Etxebeste, Ane; Ortega, Pablo G.; Lacasta, Carlos; Oliver, Josep F.; Solaz, Carles; Llosa, Gabriela] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000408229900003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3253
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Author Calatayud-Jordan, J.; Candela-Juan, C.; Palma, J.D.; Pujades-Claumarchirant, M.C.; Soriano, A.; Gracia-Ochoa, M.; Vilar-Palop, J.; Vijande, J.
Title Influence of the simultaneous calibration of multiple ring dosimeters on the individual absorbed dose Type Journal Article
Year 2021 Publication Journal of Radiological Protection Abbreviated Journal J. Radiol. Prot.
Volume 41 Issue 2 Pages 384-397
Keywords ring dosimeters; personal dosimetry; calibration; Monte Carlo; ISO 4037
Abstract Ring dosimeters for personal dosimetry are calibrated in accredited laboratories following ISO 4037-3 guidelines. The simultaneous irradiation of multiple dosimeters would save time, but has to be carefully studied, since the scattering conditions could change and influence the absorbed dose in nearby dosimeters. Monte Carlo simulations using PENELOPE-2014 were performed to explore the need to increase the uncertainty of H-p (0.07) in the simultaneous irradiation of three and five DXT-RAD 707H-2 (Thermo Scientific) ring dosimeters with beam qualities: N-30, N-80 and N-300. Results show that the absorbed dose in each dosimeter is compatible with each of the others and with the reference simulation (a single dosimeter), with a coverage probability of 95% (k = 2). Comparison with experimental data yielded consistent results with the same coverage probability. Therefore, five ring dosimeters can be simultaneously irradiated with beam qualities ranging, at least, between N-30 and N-300 with a negligible impact on the uncertainty of H-p (0.07).
Address [Calatayud-Jordan, J.] Hosp Univ Politecn La Fe, Valencia, Spain, Email: calatayud_josjor@gva.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0952-4746 ISBN Medium
Area Expedition Conference
Notes WOS:000657114600001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4850
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Author Garcia-Cases, F.; Perez-Calatayud, J.; Ballester, F.; Vijande, J.; Granero, D.
Title Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects Type Journal Article
Year 2018 Publication Journal of Radiological Protection Abbreviated Journal J. Radiol. Prot.
Volume 38 Issue 4 Pages 1393-1411
Keywords Mobetron; mobile electron linear accelerator; radiotherapy intraoperative
Abstract The aim of this work is to analyse the scattered radiation produced by the mobile accelerator Mobetron 1000. To do so, detailed Monte Carlo simulations using two different codes, Penelope2008 and Geant4, were performed. Measurements were also done. To quantify the attenuation due to the internal structures, present in the accelerator head, on the scattered radiation produced, some of the main structural shielding in the Mobetron 1000 has been incorporated into the geometry simulation. Results are compared with measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation component due to low energy scattered electrons. This encouraged us to perform additional calculations to separate the role played by this component. Ambient dose equivalent, H*(10), outside of the operating room (OR) has been evaluated using Geant4. H*(10) has been measured inside and outside the OR, being its values compatible with those reported in the literature once the low energy electron component is removed. With respect to the role played by neutrons, estimations of neutron H*(10) using Geant4 together with H*(10) measurements has been performed for the case of the 12 MeV electron beam. The values obtained agree with the experimental values existing in the literature, being much smaller than those registered in conventional accelerators. This study is a useful tool for the clinical user to investigate the radiation protection issues arising with the use of these accelerators in ORs without structural shielding. These results will also enable to better fix the maximum number of treatments that could be performed while insuring adequate radiological protection of workers and public in the hospital.
Address [Garcia-Cases, F.] Hosp Univ San Juan de Alicante, Serv Radiofis & Protecc Radiol, Alacant, Spain, Email: garcia_frad@gva.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0952-4746 ISBN Medium
Area Expedition Conference
Notes WOS:000448769200001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 3784
Permanent link to this record
 

 
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.
Title Calibration of a thermoluminescent dosimeter worn over lead aprons in fluoroscopy guided procedures Type Journal Article
Year 2018 Publication Journal of Radiological Protection Abbreviated Journal J. Radiol. Prot.
Volume 38 Issue 2 Pages 549-563
Keywords backscatter correction factor; TLD; lead apron; fluoroscopy; eye lens dose
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.
Address [Quintero-Quintero, A.; Patino-Camargo, G.] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Valencia, Spain, Email: ccanjuan@gmail.com
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0952-4746 ISBN Medium
Area Expedition Conference
Notes WOS:000428913900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3552
Permanent link to this record
 

 
Author Tarifeño-Saldivia, A.; Soto, L.
Title Effects of gas chamber geometry and gas flow on the neutron production in a fast plasma focus neutron source Type Journal Article
Year 2014 Publication Plasma Physics and Controlled Fusion Abbreviated Journal Plasma Phys. Control. Fusion
Volume 56 Issue 12 Pages 125013 - 5pp
Keywords pulsed neutron source; repetitive plasma focus; neutron yield measurement; fast plasma focus
Abstract This work reports that gas chamber geometry and gas flow management substantially affect the neutron production of a repetitive fast plasma focus. The gas flow rate is the most sensitive parameter. An appropriate design of the gas chamber combined with a suitable flow-rate management can lead to improvements in the neutron production of one order of magnitude working in a fast repetitive mode.
Address [Tarifeno-Saldivia, Ariel; Soto, Leopoldo] Comis Chilena Energia Nucl CCHEN, Santiago, Chile, Email: atarisal@gmail.com;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3335 ISBN Medium
Area Expedition Conference
Notes WOS:000346926300024 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2070
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Author Solevi, P.; Muñoz, E.; Solaz, C.; Trovato, M.; Dendooven, P.; Gillam, J.E.; Lacasta, C.; Oliver, J.F.; Rafecas, M.; Torres-Espallardo, I.; Llosa, G.
Title Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams Type Journal Article
Year 2016 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume 61 Issue 14 Pages 5149-5165
Keywords ion-beam therapy; range verification; prompt gamma; Compton camera; GATE
Abstract In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing Na-22 and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.
Address [Solevi, Paola; Munoz, Enrique; Solaz, Carles; Trovato, Marco; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosa, Gabriela] IFIC CSIC UVEG, Inst Fis Corpuscular, Valencia, Spain, Email: paola.solevi@ovgu.de
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000379555300007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2754
Permanent link to this record
 

 
Author Etxebeste, A.; Barrio, J.; Muñoz, E.; Oliver, J.F.; Solaz, C.; Llosa, G.
Title 3D position determination in monolithic crystals coupled to SiPMs for PET Type Journal Article
Year 2016 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.
Volume 61 Issue 10 Pages 3914-3934
Keywords monolithic crystal; silicon photomultiplier; depth of interaction
Abstract The interest in using continuous monolithic crystals in positron emission tomography (PET) has grown in the last years. Coupled to silicon photomultipliers (SiPMs), the detector can combine high sensitivity and high resolution, the two main factors to be maximized in a positron emission tomograph. In this work, the position determination capability of a detector comprised of a 12 x 12 x 10 mm(3) LYSO crystal coupled to an 8 x 8-pixel array of SiPMs is evaluated. The 3D interaction position of.-rays is estimated using an analytical model of the light distribution including reflections on the facets of the crystal. Monte Carlo simulations have been performed to evaluate different crystal reflectors and geometries. The method has been characterized and applied to different cases. Intrinsic resolution obtained with the position estimation method used in this work, applied to experimental data, achieves sub-millimetre resolution values. Average resolution over the detector surface for 5 mm thick crystal is similar to 0.9 mm FWHM and similar to 1.2 mm FWHM for 10 mm thick crystal. Depth of interaction resolution is close to 2 mm FWHM in both cases, while the FWTM is similar to 5.3 mm for 5 mm thick crystal and similar to 9.6 mm for 10 mm thick crystal.
Address [Etxebeste, Ane; Barrio, John; Munoz, Enrique; Oliver, Josep F.; Solaz, Carles; Llosa, Gabriela] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: ane.etxebeste@ific.uv.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9155 ISBN Medium
Area Expedition Conference
Notes WOS:000376792800014 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2708
Permanent link to this record
 

 
Author Pavez, C.; Pedreros, J.; Tarifeño-Saldivia, A.; Soto, L.
Title Observation of plasma jets in a table top plasma focus discharge Type Journal Article
Year 2015 Publication Physics of Plasmas Abbreviated Journal Phys. Plasmas
Volume 22 Issue 4 Pages 040705 - 5pp
Keywords
Abstract In the last years, medium size Z-pinch experiments operating at tens of kJ are being used to create supersonic plasma jets. Those experiments are produced with wire arrays and radial foils, and they are conducted in generators based on water-filled transmission lines. Also plasma jets have been observed in small X-pinch experiments operating at 1 kJ. In this work, observations of plasma jets produced in a table top plasma focus device by means of optical and digital interferometry are shown. The device was operated at only similar to 70J, achieving 50 kA in 150 ns. The plasma jets were observed after the pinch, in the region close and on the anode, along the axis. The electron density measured from the jets is in the range 10(24)-10(25) m(-3). From two consecutive plasma images separated 18 ns, the axial jet velocity was measured in the order of 4 x 10(4) m/s.
Address [Pavez, Cristian; Pedreros, Jose; Tarifeno-Saldivia, Ariel; Soto, Leopoldo] CCHEN, Comis Chilena Energia Nucl, Santiago, Chile, Email: lsoto@cchen.cl
Corporate Author Thesis
Publisher Amer Inst Physics Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1070-664x ISBN Medium
Area Expedition Conference
Notes WOS:000353837200006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2400
Permanent link to this record
 

 
Author ANTARES Collaboration (Andre, M. et al); Barrios-Marti, J.; Hernandez-Rey, J.J.; Illuminati, G.; Tönnis, C.; Zornoza, J.D.; Zuñiga, J.
Title Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope Type Journal Article
Year 2017 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 7 Issue Pages 45517 - 12pp
Keywords
Abstract Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.
Address [Andre, M.; Caballe, A.; Van der Schaar, M.; Solsona, A.; Houegnigan, L.; Zaugg, S.; Sanchez, A. M.; Castell, J. V.; Sole, M.; Vila, F.; Djokic, D.; Vallage, B.] Tech Univ Catalonia, Barcelona Tech UPC, LAB, Rambla Exposicio 24, Barcelona 08800, Spain, Email: michel.andre@upc.edu
Corporate Author Thesis
Publisher Nature Publishing Group Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes WOS:000399188000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3054
Permanent link to this record