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Gallardo S, Ródenas J, Verdú G. Unfolding X-ray spectra using a flat panel detector. Determination of the accuracy of the method with the Monte Carlo method. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2018.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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2
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Blázquez E, Rodríguez C, Ródenas J, Pérez de Rozas A, Campbell JM, Segalés J, Pujols J, Polo J. Evaluation of ultraviolet-C and spray-drying processes as two independent inactivation steps on enterotoxigenic Escherichia coli K88 and K99 strains inoculated in fresh unconcentrated porcine plasma. Lett Appl Microbiol 2018; 67:442-448. [PMID: 30152866 PMCID: PMC7165488 DOI: 10.1111/lam.13068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 08/04/2018] [Accepted: 08/05/2018] [Indexed: 11/28/2022]
Abstract
The objectives of this study were to assess the effectiveness of an ultraviolet (UV‐C, 254 nm) irradiation system and the spray‐drying method as two independent safety steps on inactivation of Escherichia coli K88 and K99 spiked in porcine plasma at 6·46 ± 0·04 log10 ml−1 and 6·78 ± 0·67 log10 ml−1 respectively for UV‐C method, and at 7·31 ± 0·39 log10 ml−1 and 7·66 ± 0·11 log10 ml−1, respectively for the spray‐drying method. The UV‐C method was performed at different UV light doses (from 750 to 9000 J l−1) using a pilot plant UV‐C device working under turbulent flow. Spray‐drying treatment was done at inlet temperature 220 ± 1°C and two different outlet temperatures, 80 ± 1°C or 70 ± 1°C. Results indicated that UV‐C treatment induced a 4 log10 viability reduction for both E. coli at 3000 J l−1. Full inactivation of both E. coli strains was achieved in all spray‐dried samples dehydrated at both outlet temperatures. The special UV‐C system design for turbid liquid porcine plasma is a novel treatment that can provide an additional redundant biosafety feature that can be incorporated into the manufacturing process for spray‐dried animal plasma. Significance and Impact of the Study The safety of raw materials from animal origin such as spray‐dried porcine plasma (SDPP) may be a concern for the swine industry. Ultraviolet treatment at 254 nm (UV‐C) of liquid plasma has been proposed as an additional biosafety feature in the manufacturing process of SDPP. We found that UV‐C exposure in the liquid plasma at 3000 J l−1 reduces about 4 log10 ml−1 for E. coli K88 and K99. Full inactivation of both E. coli strains was achieved in all spray‐dried samples. The incorporation of UV‐C treatment to liquid plasma improves the robustness of the SDPP manufacturing process.
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Affiliation(s)
- E Blázquez
- APC EUROPE, S.L.U. Avda, Granollers, Spain.,IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | | | - J Ródenas
- APC EUROPE, S.L.U. Avda, Granollers, Spain
| | - A Pérez de Rozas
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | | | - J Segalés
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain.,UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - J Pujols
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - J Polo
- APC EUROPE, S.L.U. Avda, Granollers, Spain.,APC Inc., Ankeny, IA, USA
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Blázquez E, Rodríguez C, Ródenas J, Saborido N, Solà-Ginés M, Pérez de Rozas A, Campbell JM, Segalés J, Pujols J, Polo J. Combined effects of spray-drying conditions and postdrying storage time and temperature on Salmonella choleraesuis and Salmonella typhimurium survival when inoculated in liquid porcine plasma. Lett Appl Microbiol 2018; 67:205-211. [PMID: 29889981 PMCID: PMC7165965 DOI: 10.1111/lam.13017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 01/18/2023]
Abstract
The objective of this study was to determine the effectiveness of the spray-drying process on the inactivation of Salmonella choleraesuis and Salmonella typhimurium spiked in liquid porcine plasma and to test the additive effect of immediate postdrying storage. Commercial spray-dried porcine plasma was sterilized by irradiation and then reconstituted (1:9) with sterile water. Aliquots of reconstituted plasma were inoculated with either S. choleraesuis or S. typhimurium, subjected to spray-drying at an inlet temperature of 200°C and an outlet temperature of either 71 or 80°C, and each spray-drying temperature combinations were subjected to either 0, 30 or 60 s of residence time (RT) as a simulation of residence time typical of commercial dryers. Spray-dried samples were stored at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days. Bacterial counts of each Salmonella spp., were completed for all samples. For both Salmonella spp., spray-drying at both outlet temperatures reduced bacterial counts about 3 logs at RT 0 s, while there was about a 5·5 log reduction at RT 60 s. Storage of all dried samples at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days eliminate all detectable bacterial counts of both Salmonella spp. SIGNIFICANCE AND IMPACT OF THE STUDY Safety of raw materials from animal origin like spray-dried porcine plasma (SDPP) may be a concern for the swine industry. Spray-drying process and postdrying storage are good inactivation steps to reduce the bacterial load of Salmonella choleraesuis and Salmonella typhimurium. For both Salmonella spp., spray-drying at 71°C or 80°C outlet temperatures reduced bacterial counts about 3 log at residence time (RT) 0 s, while there was about a 5.5 log reduction at RT 60 s. Storage of all dried samples at either 4.0 ± 3.0°C or 23.0 ± 0.3°C for 15 days was effective for eliminating detectable bacterial counts of both Salmonella spp.
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Affiliation(s)
- E Blázquez
- APC EUROPE, Granollers, Barcelona, Spain.,IRTA, Centre de Recerca en Sanitat Animal (CReSA-IRTA), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | | | - J Ródenas
- APC EUROPE, Granollers, Barcelona, Spain
| | - N Saborido
- APC EUROPE, Granollers, Barcelona, Spain
| | | | - A Pérez de Rozas
- IRTA, Centre de Recerca en Sanitat Animal (CReSA-IRTA), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | | | - J Segalés
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain.,UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - J Pujols
- IRTA, Centre de Recerca en Sanitat Animal (CReSA-IRTA), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - J Polo
- APC EUROPE, Granollers, Barcelona, Spain.,APC Inc., Ankeny, IA, USA
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Ródenas J, Gallardo S, Weirich F, Hansen W. Application of dosimetry measurements to analyze the neutron activation of a stainless steel sample in a training nuclear reactor. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Pozuelo F, Gallardo S, Querol A, Verdú G, Ródenas J. X-ray simulation with the Monte Carlo code PENELOPE. Application to Quality Control. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2012:5777-80. [PMID: 23367242 DOI: 10.1109/embc.2012.6347307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A realistic knowledge of the energy spectrum is very important in Quality Control (QC) of X-ray tubes in order to reduce dose to patients. However, due to the implicit difficulties to measure the X-ray spectrum accurately, it is not normally obtained in routine QC. Instead, some parameters are measured and/or calculated. PENELOPE and MCNP5 codes, based on the Monte Carlo method, can be used as complementary tools to verify parameters measured in QC. These codes allow estimating Bremsstrahlung and characteristic lines from the anode taking into account specific characteristics of equipment. They have been applied to simulate an X-ray spectrum. Results are compared with theoretical IPEM 78 spectrum. A sensitivity analysis has been developed to estimate the influence on simulated spectra of important parameters used in simulation codes. With this analysis it has been obtained that the FORCE factor is the most important parameter in PENELOPE simulations. FORCE factor, which is a variance reduction method, improves the simulation but produces hard increases of computer time. The value of FORCE should be optimized so that a good agreement of simulated and theoretical spectra is reached, but with a reduction of computer time. Quality parameters such as Half Value Layer (HVL) can be obtained with the PENELOPE model developed, but FORCE takes such a high value that computer time is hardly increased. On the other hand, depth dose assessment can be achieved with acceptable results for small values of FORCE.
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Affiliation(s)
- F Pozuelo
- Ingeniería Química y Nuclear department, Universitat Politècnica de València, València, Spain.
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Gallardo S, Ródenas J, Querol A, Verdú G. Application of the MTSVD unfolding method for reconstruction of primary X-ray spectra using semiconductor detectors. Progress in Nuclear Energy 2011. [DOI: 10.1016/j.pnucene.2011.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Santana H, Maier G, Ródenas J. Flowability analysis of uranium dioxide powder at different temperatures containing different lubricants. Appl Radiat Isot 2011; 69:1162-4. [DOI: 10.1016/j.apradiso.2010.10.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/19/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
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Querol A, Gallardo S, Ródenas J, Verdú G. Parametric study of the X-ray primary spectra obtained with the MTSVD unfolding method. Appl Radiat Isot 2011; 69:1112-7. [PMID: 21078558 DOI: 10.1016/j.apradiso.2010.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/30/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
The modified truncated singular value decomposition (MTSVD) unfolding method is applied to obtain primary spectra for X-ray tubes in radiodiagnostic. Three parameters - voltage, anode angle and filter thickness - of the tube are tested. Unfolded spectra are compared with theoretical extracted from IPEM-78 catalogue. A 2σ error criterion is applied to assess the minimum variations in tested parameters that permits distinguishing between close spectra.
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Affiliation(s)
- A Querol
- Universidad Politécnica de Valencia, Camí de Vera s/n 46022, Valencia, Spain.
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Santana H, Maier G, Ródenas J. Ceramic nuclear fuel mechanical resistance development by means of dynamic impact testing. Appl Radiat Isot 2011; 69:1159-61. [DOI: 10.1016/j.apradiso.2010.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/16/2010] [Accepted: 12/02/2010] [Indexed: 11/24/2022]
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Ródenas J, Abarca A, Gallardo S. Analysis of dose rates received around the storage pool for irradiated control rods in a BWR nuclear power plant. Appl Radiat Isot 2011; 69:1104-7. [PMID: 21093278 DOI: 10.1016/j.apradiso.2010.10.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 10/01/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
Abstract
BWR control rods are activated by neutron reactions in the reactor. The dose produced by this activity can affect workers in the area surrounding the storage pool, where activated rods are stored. Monte Carlo (MC) models for neutron activation and dose assessment around the storage pool have been developed and validated. In this work, the MC models are applied to verify the expected reduction of dose when the irradiated control rod is hanged in an inverted position into the pool.
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Affiliation(s)
- J Ródenas
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Camí de Vera s/n 46022, Valencia, Spain.
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Querol A, Gallardo S, Ródenas J, Verdú G. Application of the MTSVD and Tikhonov Unfolding Methods for Reconstruction of Primary X-Ray Spectra of Mammography Equipment with Silicon Detector. NUCL TECHNOL 2011. [DOI: 10.13182/nt11-a12271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A. Querol
- Universidad Politécnica de Valencia, Camino de Vera s0n 46022, Valencia, Spain
| | - S. Gallardo
- Universidad Politécnica de Valencia, Camino de Vera s0n 46022, Valencia, Spain
| | - J. Ródenas
- Universidad Politécnica de Valencia, Camino de Vera s0n 46022, Valencia, Spain
| | - G. Verdú
- Universidad Politécnica de Valencia, Camino de Vera s0n 46022, Valencia, Spain
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Gallardo S, Querol A, Ródenas J, Verdú G. Uncertainty analysis in the simulation of X-ray spectra in the diagnostic range using the MCNP5 code. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2011:389-392. [PMID: 22254330 DOI: 10.1109/iembs.2011.6090125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
An accurate knowledge of the photonic spectra emitted by X-ray tubes in radiodiagnostics is essential to better estimate the imparted dose to patients and to improve the image quality obtained with these devices. In this work, several X-ray spectra have been simulated using the MCNP5 code to simulate X-ray production in a commercial device. To validate the Monte Carlo results, simulated spectra have been compared to those extracted from the IPEM 78 database. The uncertainty associated to some geometrical features of the tube and its effect on the simulated spectra has been analyzed using the Noether-Wilks formula. This analysis has been focused on the thickness of collimators, filters, shielding and barrel shutter. Furthermore, results show that the uncertainty due to geometrical parameters (0.98% in terms of Root Mean Squared) is higher than the statistical uncertainty associated to the MCNP5 calculations.
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Affiliation(s)
- S Gallardo
- Chemical and Nuclear Engineering Department, Universidad Politécnica de Valencia, Valencia 46022, Spain.
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Tondeur F, Ródenas J, Querol A, Ortiz J, Juste B. Indoor radon measurements in the city of Valencia. Appl Radiat Isot 2010; 69:1131-3. [PMID: 21093276 DOI: 10.1016/j.apradiso.2010.10.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 10/11/2010] [Accepted: 10/22/2010] [Indexed: 11/25/2022]
Abstract
The indoor radon risk in Valencia (Spain) was studied more than twenty years ago in two surveys using different methodologies and leading to contradictory results. We report here on new indoor radon measurements with the charcoal canister technique, which confirm the low average level of indoor radon in the city, with a geometrical mean of 24 Bq/m(3) and an arithmetic mean of 27 Bq/m(3).
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Affiliation(s)
- F Tondeur
- ISIB, Haute Ecole P.-H. Spaak, rue Royale 150, B1000 Brussels, Belgium.
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Ródenas J, Gallardo S, Abarca A, Juan V. Analysis of the dose rate produced by control rods discharged from a BWR into the irradiated fuel pool. Appl Radiat Isot 2010; 68:909-12. [PMID: 19836252 DOI: 10.1016/j.apradiso.2009.09.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BWR control rods become activated by neutron reactions into the reactor. Therefore, when they are withdrawn from the reactor, they must be stored into the storage pool for irradiated fuel at a certain depth under water. Dose rates on the pool surface and the area surrounding the pool should be lower than limits for workers. The MCNP code based on the Monte Carlo method has been applied to model this situation and to calculate dose rates at points of interest.
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Affiliation(s)
- J Ródenas
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Valencia, Spain.
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15
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Polo J, Rodríguez C, Ródenas J, Morera S, Saborido N. The use of spray-dried animal plasma in comparison with other binders in canned pet food recipes. Anim Feed Sci Technol 2009. [DOI: 10.1016/j.anifeedsci.2009.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Gerardy I, Ródenas J, van Dycke M, Gallardo S, Ceccolini E. Dosimetric characterization of a brachytherapy applicator using MCNP5 modelisation and in-phantom measurements. Appl Radiat Isot 2009; 68:735-7. [PMID: 19939686 DOI: 10.1016/j.apradiso.2009.10.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A gynaecological applicator consisting of a metallic intra-uterine tube with a plastic vaginal applicator and an HDR Ir-192 source have been simulated with MCNP5 (Monte Carlo code). A solid phantom has been designed to perform measurements around the applicator with radiochromic films. The isodose curves obtained are compared with curves calculated with the F4MESH tally of MCNP5 with a good agreement. A pinpoint ionization chamber has been used to evaluate dose at some reference points.
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Affiliation(s)
- I Gerardy
- Institut Supérieur Industriel de Bruxelles, Brussels, Belgium.
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Marfà O, Cáceres R, Polo J, Ródenas J. ANIMAL PROTEIN HYDROLYSATE AS A BIOSTIMULANT FOR TRANSPLANTED STRAWBERRY PLANTS SUBJECTED TO COLD STRESS. ACTA ACUST UNITED AC 2009. [DOI: 10.17660/actahortic.2009.842.57] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Gallardo S, Ródenas J, Verdú G, Querol A. Assessment of quality control parameters for an X-ray tube using the Monte Carlo method and unfolding techniques. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2009:1367-1370. [PMID: 19964756 DOI: 10.1109/iembs.2009.5334451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Quality Control (QC) parameters for an X-ray tube such as Half Value Layer (HVL), homogeneity factor and mean photon energy, can be obtained from the primary beam spectrum. A direct Monte Carlo (MC) simulation has been used to obtain this spectrum. Indirect spectrometry procedures such as Compton scattering have been also experimentally utilized since direct spectrometry causes a pile-up effect in detectors. As well the Compton spectrometry has been simulated with the MC method. In both cases unfolding techniques shall be applied to obtain the primary spectrum. Two unfolding methods (TSVD and Spectro-X) have been analyzed. Results are compared each other and with reference values taken from IPEM Report 78 catalogue. Direct MC simulation is a good approximation to obtain the primary spectrum and hence the QC parameters. TSVD is a better unfolding method for the scattered spectrum than the Spectro-X code. An improvement of the methodology to obtain QC parameters is important in Biomedical Engineering (BME) applications due to the wide use of X-ray tubes.
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Affiliation(s)
- S Gallardo
- Chemical and Nuclear Engineering Department at the Polytechnic University of Valencia, Camí de Vera s/n 46022 Valencia, Spain.
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Burgos MC, Gallardo S, Puchades V, Verdú G, Ródenas J, Villaescusa JI. Assessment of mammography spectra using compton spectrometry techniques. Radiat Prot Dosimetry 2005; 116:627-30. [PMID: 16604714 DOI: 10.1093/rpd/nci243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The quality control of mammography units is necessary to reduce the dose imparted to women as much as possible. An accurate characterisation of the primary X-ray spectra is very useful for this purpose. Primary spectra can be obtained using Compton spectrometry techniques. In this work, a commercial spectrometer used to characterise a mammography X-ray tube has been simulated using the Monte Carlo method by means of the MCNP code. Using the developed model, a Response matrix is obtained. Owing to the fact that this matrix is ill-conditioned, the inversion is not a simple process. This problem has been solved using the truncated singular value decomposition method. Results obtained when this methodology was applied have been compared with theoretical X-ray spectra.
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Affiliation(s)
- M C Burgos
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Apartado 22012, E-46071 Valencia, Spain
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Ródenas J, Burgos MC, Zarza I, Gallardo S. Simulation of germanium detector calibration using the Monte Carlo method: comparison between point and surface source models. Radiat Prot Dosimetry 2005; 116:55-8. [PMID: 16604596 DOI: 10.1093/rpd/nci111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Simulation of detector calibration using the Monte Carlo method is very convenient. The computational calibration procedure using the MCNP code was validated by comparing results of the simulation with laboratory measurements. The standard source used for this validation was a disc-shaped filter where fission and activation products were deposited. Some discrepancies between the MCNP results and laboratory measurements were attributed to the point source model adopted. In this paper, the standard source has been simulated using both point and surface source models. Results from both models are compared with each other as well as with experimental measurements. Two variables, namely, the collimator diameter and detector-source distance have been considered in the comparison analysis. The disc model is seen to be a better model as expected. However, the point source model is good for large collimator diameter and also when the distance from detector to source increases, although for smaller sizes of the collimator and lower distances a surface source model is necessary.
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Affiliation(s)
- J Ródenas
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Apartado 22012, E-46071 Valencia, Spain.
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Gallardo S, Ródenas J, Verdú G, Villaescusa JI. Analysis of shielding materials in a Compton spectrometer applied to x-ray tube quality control using Monte Carlo simulation. Radiat Prot Dosimetry 2005; 115:375-9. [PMID: 16381749 DOI: 10.1093/rpd/nci244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A realistic characterisation of the primary beam is very important for the quality control of X-ray tubes. The most accurate technique to assess the actual photon spectrum is X-ray spectrometry. Some difficulties arising in the spectrum determination can be avoided using a Compton spectrometer. Simulation models are useful tools to know the effect of some operational parameters, such as collimation of primary beam, relative position of focus and detector, and the influence of shielding materials. A simulation model has been developed using the MCNP code, based on the Monte Carlo method, in order to reproduce a commercial Compton spectrometer. In this work, the model developed is applied to analyse the influence on measurements of shielding materials present in the spectrometer.
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Affiliation(s)
- S Gallardo
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Apartado 22012, E-46071 Valencia, Spain
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Ródenas J, Zarza I, Burgos MC, Felipe A, Sánchez-Mayoral ML. Developing a virtual reality application for training nuclear power plant operators: setting up a database containing dose rates in the refuelling plant. Radiat Prot Dosimetry 2004; 111:173-180. [PMID: 15266073 DOI: 10.1093/rpd/nch043] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Operators in Nuclear Power Plants can receive high doses during refuelling operations. A training programme for simulating refuelling operations will be useful in reducing the doses received by workers as well as minimising operation time. With this goal in mind, a virtual reality application is developed within the framework of the CIPRES project. The application requires doses, both instantaneous and accumulated, to be displayed at all times during operator training. Therefore, it is necessary to set up a database containing dose rates at every point in the refuelling plant. This database is based on radiological protection surveillance data measured in the plant during refuelling operations. Some interpolation routines have been used to estimate doses through the refuelling plant. Different assumptions have been adopted in order to perform the interpolation and obtain consistent data. In this paper, the procedures developed to set up the dose database for the virtual reality application are presented and analysed.
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Affiliation(s)
- J Ródenas
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, Apartado 22012 E-46071 Valencia, Spain.
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23
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Gallardo S, Ródenas J, Verdú G. Monte Carlo simulation of the Compton scattering technique applied to characterize diagnostic x-ray spectra. Med Phys 2004; 31:2082-90. [PMID: 15305461 DOI: 10.1118/1.1759827] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The quality control of x-ray tubes for medical radiodiagnostic services is very important for such devices. Therefore, the development of new procedures to characterize the x-ray primary beam is highly interesting in order to obtain an accurate assessment of the actual photon spectrum. The Compton scattering technique is very useful to determine x-ray spectra (in the 10-150 kVp range), avoiding a pile-up effect in the detector since a large room is not usually available to apply other techniques. In this work, this process has been simulated using a Monte Carlo code, MCNP 4C. Some geometrical models have been developed and different techniques have been studied in order to improve statistics and accuracy in the acquisition of Pulse Height Distribution (PHD). The effect of both the collimation of the primary beam and the scattering angle of the spectrometer has been analyzed. Results obtained using simulation models have been compared with experimental measurements.
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Affiliation(s)
- S Gallardo
- Departamento de Ingeniería Química y Nuclear, Universidad Politécnica de Valencia, 46071 Valencia, Spain
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Marín-Blazquez AA, Candel MF, Parra PA, Méndez M, Ródenas J, Rojas MJ, Carrión F, Madrigal M. Morgagni hernia: repair with a mesh using laparoscopic surgery. Hernia 2003; 8:70-2. [PMID: 14634839 DOI: 10.1007/s10029-003-0145-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2002] [Accepted: 04/14/2003] [Indexed: 10/26/2022]
Abstract
The aim of this study is to present two patients diagnosed with diaphragmatic Morgagni hernia and treated by repairing the hernia defect with a mesh by laparoscopic surgery. We describe the placement of a double-layer mesh anchored with helicoidal staples to repair the hernia defect using laparoscopic surgery. Laparoscopic surgery allows repair of these defects whilst avoiding the disadvantages of a major laparotomy or a thoracotomy. The existence of double-layer meshes that can be placed in contact with the abdominal viscera allows the defect to be closed safely and without tension.
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Carbonell T, Ródenas J, Alfaro V, Mitjavila MT, Palacios L. Extracellular pH affects inflammatory cell production of superoxide and nitric oxide. J Physiol Biochem 2002; 58:115-20. [PMID: 12435087 DOI: 10.1007/bf03179847] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Previous research has described how high cellular metabolism creates an acidic environment in inflammatory cells during respiratory burst. The aim of our work was to describe the acid-base dependence of exudate in superoxide (O2.-) and nitric oxide (NO.) generation by inflammatory cells from a carrageenan-granuloma. Although the carrageenan solution was alkaline (pH 7.74 when equilibrated with air) the exudate showed an acidification that stabilised at around 7 units of pH. A notable hypercapnia, but not hypoxia, was found in the exudate at up to 24 h. The effect of extracellular acidosis on O2.- and NO. production by inflammatory cells was also studied. The maximum O2.- production and the lowest levels of NO. were found at pH 7, which was closer to the pH of the granuloma-pouch. These results suggest that experiments with inflammatory cells ex vivo should be carried out at an identical pH to that found in vivo in order to reproduce the physiological mechanisms of free radical generation during inflammatory processes.
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Affiliation(s)
- T Carbonell
- Departament de Fisiologia, Universitat de Barcelona, Spain
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26
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Abstract
A complete method is presented for the evaluation of photoneutron spectra produced in linear accelerators for cancer radiotherapy. It consists of a computer simulation code based on the MCNP4B Monte Carlo code, in which the new routine GAMMAN was implemented, allowing the accurate study of photoneutron production in high Z elements. In addition an experimental method based on a passive bubble spectrometer allows direct measurements of the photoneutron spectrum at the patient plane, also under the photon beam. The results are presented both for a 15 MeV linac with a traditional collimator system and for an 18 MeV linac equipped with a multileaf collimator, used in conformational radiotherapy.
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Affiliation(s)
- C Ongaro
- Dipartimento di Fisica Sperimentale, Università di Torino, Italy.
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Ródenas J, Martinavarro A, León A, Verdú G. Application of the Monte Carlo Method to Shielding Analysis in Medical Linear Accelerators. J NUCL SCI TECHNOL 2000. [DOI: 10.1080/00223131.2000.10874924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
We studied the roles of nitrogen monoxide (NO&z.rad;) and peroxynitrite produced by the polymorphonuclear leukocytes (PMNs) isolated from an inflammatory exudate. PMNs were incubated either in a medium with a submicromolar concentration of iron or in a diethylenetriaminepenta-acetic acid (DTPA)-containing medium, and stimulated with phorbol 12-myristate 13-acetate (PMA) to generate free radicals. In both conditions superoxide anion (O(2)(*)(-)), NO&z.rad; and peroxynitrite were produced. In the presence of arachidonic acid, malondialdehyde (MDA) was generated. This MDA was generated in one of two way; the peroxynitrite iron-independent mechanism (40%) and the Fenton reaction, caused by free iron (60%). We also observed that the addition of L-arginine was followed by a 42% reduction in MDA, which can be explained by the antioxidant effect of NO&z.rad;. These results indicate that lipid peroxidation can occur in the absence of iron, through a peroxynitrite-mediated mechanism, and that NO&z.rad; may act as an antioxidant when it is produced in large amounts.
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Affiliation(s)
- J Ródenas
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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29
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Abstract
Nitric oxide (NO.) has a complex role in the inflammatory response. In this study, we modified the levels of endogenous NO. in vivo in an acute model of inflammation and evaluated the interactions between NO. and superoxide anion (O2-.) produced by polymorphonuclear leukocytes (PMNs) accumulated in the inflamed area. We injected phosphate-buffered saline (control group), 6 mumol of L-N5-(1-iminoethyl)ornithine (L-NIO group), or 6 mumol of L-arginine (L-arginine group) into the granuloma pouch induced by carrageenan in rats. NO2- plus NO3- (indicative of NO. generation) was 188 nmol in the exudate of the control group, but it decreased in the L-NIO group (P < 0.05) and increased in the L-arginine group (P < 0.05). When PMNs from treated rats were incubated in vitro, the production of superoxide anion (O2-.) decreased by approximately 46% in the L-arginine group. Furthermore, O2-. was inhibited in PMNs when L-arginine was added to the incubation medium before phorbol 12-myristate 13-acetate stimulation but not when added simultaneously. Our results suggest a protective role for NO. in inflammation, through the inactivation of NADPH oxidase and the consequent impairment of O2-. production for cell-mediated injury.
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Affiliation(s)
- J Ródenas
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain
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Abstract
We investigated the effects of diets with different fatty acid composition upon the oxidative stress of inflammatory leukocytes of rats. After weaning, two groups of rats were fed isoenergetic semipurified diets for five weeks containing 5% of corn oil or menhaden oil. Polymorphonuclear leukocytes from rats fed menhaden oil diet incorporated n-3 polyunsaturated fatty acids into phospholipid membranes at the expense of arachidonic acid. These cells showed diminished superoxide production and, as a consequence, the total antioxidant status in the inflammatory exudate was increased. However, nitric oxide production was not affected by diet. Free malondialdeyde concentration increased in the exudate because of lower mitochondrial activity. These results add new aspects that help clarifying the anti-inflammatory mechanisms of n-3 polyunsaturated fatty acids.
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Affiliation(s)
- T Carbonell
- Department of Physiology, Faculty of Biology, University of Barcelona, Spain
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Alfaro V, Ródenas J, Pesquero J, Mitjavila MT, Palacios L, Carbonell T. Factors influencing the acid-base changes in the air-pouch exudate following carrageenan induced inflammation in rats. Inflamm Res 1996; 45:405-11. [PMID: 8872514 DOI: 10.1007/bf02252936] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The interactions between the acid-base variables that contribute to exudate acidosis were studied in the subcutaneous air-pouch after carrageenan injection in rats. We studied the concurrent changes of exudate gases (PCO2 and PO2), main ions ([Na+], [K+], [Ca2+], [Mg2+], [Cl-] and [Lac-]), inorganic phosphate (P(i)) and albumin in acutely inflamed rats (4, 8, 12, 24 and 48 h of inflammation). A notable hypercapnia was found in the exudate after only 8 h (exudate PCO2 = 64.3 +/- 2.9 mm Hg) but this hypercapnia decreased after 48 h (32.9 +/- 12.7 mm Hg), coincident with the greatest increase in exudate cells. With respect to the metabolic acid-base variables, the most important changes found were a parallel decrease in the strong ion difference ([SID]) and exudate pH, as well as increases in the exudate weak acid buffers ([ATOT]) due to albumin and inorganic phosphate (P(i)) increases. However, after 12 h, the exudate acidosis was stable at around pH 7. A similar acid pH was obtained after 24 h of inflammation when the carrageenan solution injected was previously adjusted to a physiological pH (7.4). This pH, analogous to that of the exudate, was the result of compensation by the acid-base independent variables, a fact which suggests that acid pH may be a beneficial condition for cells taking part in inflammatory processes.
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Affiliation(s)
- V Alfaro
- Department of Physiology, University of Barcelona, Spain
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Ródenas J, Carbonell T, Mitjavila MT. Conditions to study nitric oxide generation by polymorphonuclear cells from an inflammatory exudate in rats. Arch Biochem Biophys 1996; 327:292-4. [PMID: 8619617 DOI: 10.1006/abbi.1996.0124] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Superoxide and nitric oxide release by leukocytes has been usually performed after exposure to a particular stimulus. We measured the generation of superoxide and nitric oxide by cells isolated from an inflammatory exudate of rats in either the absence or the presence of a variety of stimuli. Nonstimulated leukocytes generated superoxide radical (1.2 nmol x 10(6) cells(-1)) and nitric oxide (3.8 nmol x 10(6) cells(-1)) after 2 h incubation. When cells were incubated with lipopolysaccharides, opsonized zymosan or phorbol 12-myristate 13-acetate, superoxide level increased while nitric oxide decreased. Phorbol 12-myristate 13-acetate (100 ng/ml) induced a decrease of 0.88 nmol x 10(6) cells(-1) compared with nonstimulated cells, and incubation with N-iminoethyl-L-ornithine increased superoxide production by 0.81 nmol x 10(6) cells(-1). These results provide clear evidence that cells from an inflammatory exudate which are already triggered are able to generate a considerable amount of nitric oxide and in less proportion superoxide, that the measure of nitric oxide must be performed without a further stimulus, and that both molecules react in an equimolar proportions to give peroxynitrite anion.
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Affiliation(s)
- J Ródenas
- Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain
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Alfaro V, Ródenas J, Palaclos L, Mitjavila MT, Carbonell T. Blood acid-base changes during acute experimental inflammation in rats. Can J Physiol Pharmacol 1996; 74:313-9. [PMID: 8773412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Acidosis has often been reported in inflamed tissues, and changes in strong relevant ions at the site of inflammation may provoke alterations in blood acid-base status. We measured changes in blood acid-base variables during carrageenan-induced inflammation in rats. We found a mixed acid-base disorder in rat blood during acute inflammation (12, 24, and 48 h). A metabolic acid contribution was found during the first 12 h and maintained further, as revealed by a decrease in plasma strong ion concentration difference ([SID]) and an increase in plasma weak acid concentration due to a rise in inorganic phosphate ([ATOT]P(i)). Plasma [SID] and [ATOT]P(i) changes were probably due to exchange of Na+ and P(i) between the inflammatory exudate and rat blood. A secondary respiratory compensation for the metabolic acid changes occurred in the blood of inflamed rats, resulting in significant hypocapnia. Furthermore, a progressive decrease in the total weak acid buffer concentration due to a decrease in plasma albumin ([ATOT]Alb) also counteracted the impact of changes in [SID] and P(i) to increase blood acidity. Therefore, despite the metabolic acid-base disorders induced by inflammatory processes, hydrogen ion (H+) homeostasis was maintained, and blood pH remained essentially unchanged in the inflamed rats.
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Affiliation(s)
- V Alfaro
- Department of Physiology, Faculty of Biology, University of Barcelona, Spain
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34
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Alfaro V, Ródenas J, Palacios L, Mitjavila MT, Carbonell T. Blood acidbase changes during acute experimental inflammation in rats. Can J Physiol Pharmacol 1996. [DOI: 10.1139/y96-023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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35
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Alfaro V, Ródenas J, Palacios L, Mitjavila M, Carbonell T. Blood acid–base changes during acute e×perimental inflammation in rats. Can J Physiol Pharmacol 1996. [DOI: 10.1139/cjpp-74-3-313] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Abstract
It has recently been shown that peroxynitrite anion is a powerful oxidant than can initiate lipid peroxidation. As this oxidant is the product of the reaction between nitric oxide and superoxide, we have studied whether cells isolated from an inflammatory exudate can release both radicals simultaneously under physiological conditions. The carrageenin-induced granuloma model in rats was used. Cells from the inflammatory pouch were stimulated with opsonized zymosan in the absence or in the presence of exogenous L-arginine. Nitric oxide production without exogenous L-arginine was detectable after 15 min (0.29 nmol NO2-) and increased with time (1.65 nmol NO2- at 4 h). When nitrite released from cells was expressed as a rate a burst was shown in the first few minutes. Between 0 and 15 min, cells produced NO2- at the following rates: 20 pmol NO2-/1 x 10(6) cells/min without exogenous L-arginine and 83 pmol NO2-/1 x 10(6) cells/min with exogenous L-arginine. Production was further stimulated with opsonized zymosan (92 pmol NO2-/1 x 10(6) cells/min), and inhibited by L-NMMA and L-NIO. The production of superoxide increased for up to 2 h and then stabilized. A significant increase in nitrite was observed in the presence of SOD, whereas L-NIO increased superoxide generation. These results suggest that peroxynitrite anion may be formed by inflammatory cells.
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Affiliation(s)
- J Ródenas
- Unitat de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain
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