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Sample records for dosimetric applications desarrollo

  1. Dosimetry in radiodiagnosis. Individual irradiation card. Dosimetric application of electrets

    International Nuclear Information System (INIS)

    Lisbona, Albert.

    1981-09-01

    This study deals with a radiodiagnosis dosimetry, and contains two parts. First of all, the combination between a dosimetric data acquisition from an ionization chamber and a micro-computer allows the realization of individual irradiation card for a well established examination. The method is extensible to almost totality of radiological examinations. The second part describes the following of an original work about the application of electrets in radiodiagnosis dosimetry. At least a theorical study is shown; it takes account of different involving phenomena and allows a starting interpretation of experimental results [fr

  2. Applications of sensitivity function to dosimetric data adjustments

    International Nuclear Information System (INIS)

    Nakazawa, Masaharu

    1984-01-01

    Sensitivity functions are applied to the dosimetric field in the spectrum unfolding technique, also called as the data adjustment technique which are statistical estimation procedures of the neutron spectrum or relating dosimetric quantities basing on the reaction-rate data measurements. Using the practical formulae and numerical examples of the sensitivity functions in the dosimetric data adjustments, two comments are made that (1) present sensitivity values are highly depending on the initial spectrum inputs and (2) more attention should be paid to the dependency of the sensitivity on the very uncertain covariance data inputs of the initial neutron spectrum. (author)

  3. Dosimetric applications of the new ICRP lung model

    International Nuclear Information System (INIS)

    James, A.C.

    1994-06-01

    The International Commission on Radiological Protection (ICRP) has adopted a new dosimetric model of the human respiratory tract, to be issued as ICRP Publication 66. This chapter presents a summary of the main measures of the new model. The model is a general update of that in Publication 30, but is significantly broader in scope. It applies explicitly to workers and all members of the public: for inhalation of particles, gases and vapors; evaluation of dose per unit intake or exposure; and interpretation of bioassay data. The approach is fundamentally different from the Publication 30 model which calculates only the average dose to the lungs. The new model takes account of differences in radiosensitivity of respiratory tract tissues, and the wide range of doses they may receive, and calculates specific tissue doses. The model readily incorporates specific information related to the subject (age, physical activity, smoking or health status) or the exposure (aerosol size and chemical form). The application of the new model to calculate equivalent lung dose and effective dose per unit intake is illustrated for several α- and ∂-emitting radionuclides, and the new values obtained are compared with those given by the ICRP Publication 30 lung model

  4. Dosimetric study in iodine-125 seeds for brachytherapy application

    International Nuclear Information System (INIS)

    Zeituni, Carlos Alberto

    2008-01-01

    The demand for iodine-125 seeds for use in brachytherapy treatments has experienced an increase along recent years in Brazil and all over the world. All iodine-125 seed must have its operational parameters measured and/or calculated every time changes in the production process are carried out. A complete dosimetric measurement is very expensive, and it is recommended that this procedure must be repeated at least once a year. Thus, this work developed a methodology for the entire dosimetric process. This methodology is based on the scarce information available in the literature, once almost all the methodology used in large industrial laboratories is commercial secret. The proposed methodology was tested using seeds of Amersham-Oncura-Ge Healthcare, which is the largest seed manufactory in the world. In this new methodology, an automatic reader was employed in order to reduce the time required in the selection process of the TLD-100 dosimeters used and a postprocessing of the obtained spectra was carried out. A total of 142 dosimeters were used and only 29 have been selected using the new methodology. Measurements were performed using slabs of Solid Water RW1 to simulate measuring in the 'water', using three different experimental apparatus and each measurement was repeated at least three times. The TLD-100 calibration was performed using a Dermopan II - Siemens. The measured values showed a good agreement with the ones available in the literature. Finally, these measured values were compared with calculated ones obtained by a semiempirical simulation program, showing a good agreement and, therefore, demonstrating the validity of the proposed methodology regarding dosimetric calculations. (author)

  5. Production of LiF films for dosimetric thermoluminescence application

    International Nuclear Information System (INIS)

    Mauricio, Claudia Lucia de Pinho

    2000-12-01

    This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F 2 NaF and Cu F 2 to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a 60 Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F 2 : LiF; Mg F 2 films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F 2 : LiF: Mg F 2 films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F 2 layer to the LiF layer. The TL volumetric sensitivity of these

  6. Toward a nomenclature and dosimetric scheme applicable to all radiations

    Energy Technology Data Exchange (ETDEWEB)

    Rupert, C S; Latarjet, R [Texas Univ., Dallas (USA)

    1978-07-01

    An informal Joint Working Group on Radiation Quantities, consisting of representatives of the ICRU and other international organizations was initiated at the International Congress of Radiation Research in 1974. The conclusions of a meeting of the Group held in 1975 are summarised. Quantities are proposed to describe any type of radiation field in terms of the total amount of energy carried by the radiation and its distribution with respect to time, area, volume and solid angle, expressed in terms of either radiant energy (joules) or number of particles. If this general approach is agreed to by the parent organizations and others the Group will go on to recommend quantities to represent the interactions of fields with matter and to provide a dosimetric scheme usable with all types of radiation.

  7. The TL and OSL study of hydroxyapatites for dosimetric applications

    International Nuclear Information System (INIS)

    Alencar, Marcus A. Vallim de

    2009-01-01

    The hydroxyapatite, the principal mineral component of the bone and tooth enamel, is one of the dosimetric materials that has distinguished itself in the high dose and accidents dosimetry, as well as in the dating, for the Electron Paramagnetic Resonance (EPR) technique. For this reason, the hydroxyapatite could also be used as Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) dosimeter in the dosimetry of high doses and accidents, and also in the archaeological and geological dating. This work presents a brief study of the TL and OSL behaviour of the B type synthetic carbonated hydroxyapatite, observing the possibility to use this material in TL and OSL dosimetry. The samples were irradiated to a dose of 100 Gy and 1000 Gy, and the TL and OSL measurements were obtained by the RISOE TL/OSL reader, model TL/OSL-DA-15B. The first results demonstrate the presence of three peaks in the TL glow curve in the temperatures of 100 deg C, 150 deg C and 280 deg C. The synthetic carbonated hydroxyapatite also presents an OSL signal when the sample is stimulated with blue light and a small OSL signal for stimulation with infrared light (IR). These results indicate the possibility of this synthetic carbonated hydroxyapatite to be used as dose indicator material using the TL and OSL techniques. (author)

  8. Development and application of a dosimetric methodology of therapeutic X radiation beams using a tandem system

    International Nuclear Information System (INIS)

    Sartoris, Carla Eri

    2001-01-01

    In radiotherapy the use of orthovoltage X radiation beams is still recommended; to obtain satisfactory results, a periodic control is necessary to check the performance of the ionization chambers and the radiation beams characteristics. This control is performed by using standard dosimetric procedures, as for example the determination of half-value layers and the absorbed dose rates. A Tandem system was established in this work using a pair of ionization chambers (a thimble type and a superficial type) used for measures in a medical institution, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The results obtained show the application of this method in dosimetric procedures of orthovoltage beams (radiotherapy) as a complement for a quality control program. (author)

  9. Dosimetric characterization of a bi-directional micromultileaf collimator for stereotactic applications.

    Science.gov (United States)

    Bucciolini, M; Russo, S; Banci Buonamici, F; Pini, S; Silli, P

    2002-07-01

    A 6 MV photon beam from Linac SL75-5 has been collimated with a new micromultileaf device that is able to shape the field in the two orthogonal directions with four banks of leaves. This is the first clinical installation of the collimator and in this paper the dosimetric characterization of the system is reported. The dosimetric parameters required by the treatment planning system used for the dose calculation in the patient are: tissue maximum ratios, output factors, transmission and leakage of the leaves, penumbra values. Ionization chambers, silicon diode, radiographic films, and LiF thermoluminescent dosimeters have been employed for measurements of absolute dose and beam dosimetric data. Measurements with different dosimeters supply results in reasonable agreement among them and consistent with data available in literature for other models of micromultileaf collimator; that permits the use of the measured parameters for clinical applications. The discrepancies between results obtained with the different detectors (around 2%) for the analyzed parameters can be considered an indication of the accuracy that can be reached by current stereotactic dosimetry.

  10. Development of materials with dosimetric applications; Desarrollo de materiales con aplicaciones dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza A, D.; Perez H, R.; Gonzalez, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Estrada G, R. [UIA, Unidad Santa Fe, 01000 Mexico D.F. (Mexico); Salas C, P. [IMP, 07000 Mexico D.F. (Mexico)

    2003-07-01

    The thermoluminescence (Tl) is a property that have certain materials, of emitting light thermally stimulated, when they have been exposed to a field of ionizing radiation. In this work an analysis of the Tl response induced by the gamma radiation in the zircon, titania and hydroxyapatite is presented. First the influence of the presence of graphite in the Tl response of the zircon is analyzed, next the sensitivity of the titania thermally treated to different temperatures is analyzed. Finally the Tl response produced by the hydroxyapatite synthesized by two different processes is studied. (Author)

  11. Characterization of natural topaz for dosimetric applications in the therapeutic range

    International Nuclear Information System (INIS)

    Souza, Divanizia do Nascimento

    2002-01-01

    The thermoluminescence (TL) and the thermally stimulated exoelectron emission of Brazilian natural topaz samples from Minas Gerais were analysed aiming the use of this mineral for dosimetric applications. Topaz is an aluminium fluorosilicate with a fairly constant chemical composition of Al 2 SiO 4 (F,OH) 2 . The major variation in the structure among different samples is related to the OH/F concentration ratio. In the present work, samples cut from rolled pebbles, powdered samples and composites were used. The composites (dosimeters) were prepared with powdered topaz embedded in powdered Teflon or glass. The dosimetric characterization of the composites showed that the dosimeters present a linear response in the range of therapeutic doses, slow isothermic fading and a strong TL dependence with radiation energy. The TL was also combined with the X-ray diffraction, infrared and Raman spectroscopic techniques to identify the charge carrier traps and those of the recombination centres, that are essential aspects to understand the processes of light emission in natural colourless topaz. It was observed that the main charge trapping centers in the topaz are due to various OH-related defects, and that the thermal treatments can change the concentration of the recombination centers. Implantations with chromium, aluminium and iron ions into colourless samples were performed, and they were efficient to produce TL modifications in topaz. (author)

  12. Dosimetric evaluation of a MOSFET detector for clinical application in photon therapy.

    Science.gov (United States)

    Kohno, Ryosuke; Hirano, Eriko; Nishio, Teiji; Miyagishi, Tomoko; Goka, Tomonori; Kawashima, Mitsuhiko; Ogino, Takashi

    2008-01-01

    Dosimetric characteristics of a metal oxide-silicon semiconductor field effect transistor (MOSFET) detector are studied with megavoltage photon beams for patient dose verification. The major advantages of this detector are its size, which makes it a point dosimeter, and its ease of use. In order to use the MOSFET detector for dose verification of intensity-modulated radiation therapy (IMRT) and in-vivo dosimetry for radiation therapy, we need to evaluate the dosimetric properties of the MOSFET detector. Therefore, we investigated the reproducibility, dose-rate effect, accumulated-dose effect, angular dependence, and accuracy in tissue-maximum ratio measurements. Then, as it takes about 20 min in actual IMRT for the patient, we evaluated fading effect of MOSFET response. When the MOSFETs were read-out 20 min after irradiation, we observed a fading effect of 0.9% with 0.9% standard error of the mean. Further, we applied the MOSFET to the measurement of small field total scatter factor. The MOSFET for dose measurements of small field sizes was better than the reference pinpoint chamber with vertical direction. In conclusion, we assessed the accuracy, reliability, and usefulness of the MOSFET detector in clinical applications such as pinpoint absolute dosimetry for small fields.

  13. SU-E-J-167: Dosimetric Consequences From Minimal Displacements in APBI with SAVI Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekara, S; Dumitru, N [Bucharest (Romania); Hyvarinen, M [Florida Atlantic University, Boca Raton, FL (United States); Pella, S [South Florida Radiation Oncology, Boca Raton, FL (United States)

    2015-06-15

    Purpose: To determine the importance of providing proper solid immobilization in every fraction of treatment in APBI with brachytherapy. Methods: 125 patients treated with APBI brachytherapy with SAVI applicators at SFRO Boca Raton, from 2013–2015 were considered for this retrospective study. The CT scans of each patient, which were taken before each treatment, were imported in to the Oncentra treatment planning system. Then they were compared with the initial CT scan which was used for the initial plan. Deviation in displacements in reference to ribs and skin surface was measured and dosimetric evaluations respective to the initial image were performed. Results: Small deviations in displacements were observed from the SAVI applicator to the ribs and the skin surface. Dosimetric evaluations revealed, very small changes in the inter-fractionation position make significant differences in the maximum dose to critical organs. Additionally, the volume of the cavity also changed between fractions. As a Result, the maximum dose manifested variance between 10% and 32% in ribs and skin surface respectively. Conclusion: It appears that taking a CT scan before each treatment is necessary to minimize the risk of delivering undesired high doses to the critical organs. This study indicates, in 30% of the cases re-planning was necessary between treatments. We conclude that, treatment planning teams should evaluate the placement of the device by analyzing the CT images before each treatment and they must be prepared for re-planning if needed. This study also reveals the urgent need of improving the immobilization methods with APBI when treating with the SAVI applicator.

  14. Characterization of the a-Si EPID in the unity MR-linac for dosimetric applications

    Science.gov (United States)

    Torres-Xirau, I.; Olaciregui-Ruiz, I.; Baldvinsson, G.; Mijnheer, B. J.; van der Heide, U. A.; Mans, A.

    2018-01-01

    Electronic portal imaging devices (EPIDs) are frequently used in external beam radiation therapy for dose verification purposes. The aim of this study was to investigate the dose-response characteristics of the EPID in the Unity MR-linac (Elekta AB, Stockholm, Sweden) relevant for dosimetric applications under clinical conditions. EPID images and ionization chamber (IC) measurements were used to study the effects of the magnetic field, the scatter generated in the MR housing reaching the EPID, and inhomogeneous attenuation from the MR housing. Dose linearity and dose rate dependencies were also determined. The magnetic field strength at EPID level did not exceed 10 mT, and dose linearity and dose rate dependencies proved to be comparable to that on a conventional linac. Profiles of fields, delivered with and without the magnetic field, were indistinguishable. The EPID center had an offset of 5.6 cm in the longitudinal direction, compared to the beam central axis, meaning that large fields in this direction will partially fall outside the detector area and not be suitable for verification. Beam attenuation by the MRI scanner and the table is gantry angle dependent, presenting a minimum attenuation of 67% relative to the 90° measurement. Repeatability, observed over two months, was within 0.5% (1 SD). In order to use the EPID for dosimetric applications in the MR-linac, challenges related to the EPID position, scatter from the MR housing, and the inhomogeneous, gantry angle-dependent attenuation of the beam will need to be solved.

  15. SU-F-T-63: Dosimetric Relevance of the Valencia and Leipzig HDR Applicators Plastic Cap

    Energy Technology Data Exchange (ETDEWEB)

    Granero, D [ERESA-Hospital General Universitario, Valencia (Spain); Candela-Juan, C [National Dosimetry Centre (CND), Valencia (Spain); Vijande, J; Ballester, F [University of Valencia, Burjassot (Spain); Perez-Calatayud, J [Hospital La Fe, Valencia (Spain); Jacob, D; Mourtada, F [Helen F. Graham Cancer Center, Christiana Care Health System, Newark, DE (United States)

    2016-06-15

    Purpose: Utilization of HDR brachytherapy treatment of skin lesions using collimated applicators, such as the Valencia or Leipzig is increasing. These applicators are made of cup-shaped tungsten material in order to focalize the radiation into the lesion and to protect nearby tissues. These applicators have an attachable plastic cap that removes secondary electrons generated in the applicator and flattens the treatment surface. The purpose of this study is to examine the dosimetric impact of this cap, and the effect if the cap is not placed during the HDR fraction delivery. Methods: Monte Carlo simulations have been done using the code Geant4 for the Valencia and Leipzig applicators. Dose rate distributions have been obtained for the applicators with and without the plastic cap. An experimental study using EBT3 radiochromic film has been realized in order to verify the Monte Carlo results. Results: The Monte Carlo simulations show that absorbed dose in the first millimeter of skin can increase up to 180% for the Valencia applicator if the plastic cap is absent and up to 1500% for the Leipzig applicators. At deeper distances the increase of dose is smaller being about 10–15%. Conclusion: Important differences have been found if the plastic cap of the applicators is absent in the treatment producing an overdosage in the skin. The user should have a checklist to remind him check always before HDR fraction delivery to insure the plastic cap is placed on the applicator. This work was supported in part by Generalitat Valenciana under Project PROMETEOII/2013/010, by the Spanish Government under Project No. FIS2013-42156, and by a research agreement with Elekta Brachytherapy, Veenendaal, The Netherlands.

  16. Development of a dosimetric system for 90Sr + 90Y betatherapy applicators

    International Nuclear Information System (INIS)

    Coelho, Talita Salles

    2010-01-01

    The 90 Sr+ 90 Y applicators, used in betatherapy for prevention of keloids and pterigium, are imported and many times their dosimetric features are shown only in an illustrated form by the manufacturers. The exhaustive routine of the medical physicists in the clinic do not make possible the accomplishment of procedures for the confirmation of these parameters. This work presents the development of a methodology for the dosimetry of 90 Sr+ 90 Y betatherapy applicators. The Monte Carlo code MCNP5 was used for the simulation of the percentage depth dose curves and dose distribution profiles produced by these applicators. The experimental measurements of the radial and axial radiation attenuation, have been done with a mini-extrapolation chamber, thermoluminescent dosimeters and radiographic films. The experimental results have been compared with the simulated values. Both percentage depth dose curves and the radial dose profiles, the theoretical and the experimental ones, have presented good agreement, which may validate the use of the MCNP5 for these simulations, confirming the viability of the usage of this method in procedures of beta emitter sources dosimetry. (author)

  17. Dosimetric comparison of electron beam and 90Sr+90Y applicator for keloids treatment

    International Nuclear Information System (INIS)

    Coelho, Talita S.; Tada, Ariane; Antonio, Patricia L.; Yoriyaz, Helio; Fernandes, Marco A.R.

    2009-01-01

    Studies have been shown that among several methods that have been used for the treatment of keloids the surgical excision followed by the adjuvant radiotherapy presents the lowest relapsed rate of the injury. In this work a comparative dosimetric study has been performed using a 4 MeV electron beam from a Varian Clinac 2100C linear accelerator at the radiotherapy service of the Hospital das Clinicas of UNESP-HC, Botucatu-SP and an Amershan 90 Sr+ 90 Y brachytherapy applicator with 1491 MBq of activity. Percentage depth dose curves from ionization chamber measurements and through Monte Carlo simulation have been obtained and compared. Dose measurements have been obtained using parallel plates ionization chamber (Esradin A12) and extrapolation mini-chamber developed at IPEN. The dose calculations have been obtained using the well-known Monte Carlo radiation transport code MCNP-4C. Maximum dose differences obtained between measured/calculated values for 90 Sr+ 90 Y applicator and for the electron beam were, respectively: 7.8 % and 8.0%. The profiles of the depth and superficial tissue dose distribution produced by the electron beam revealed themselves flatter and more homogeneous than those produced by the 90 Sr+ 90 Y applicator, especially to wider fields, which cannot be obtained with beta therapy applicators because of their geometric limitations. In conclusion this present work has shown that 90 Sr+ 90 Y applicators could be efficient for small and very superficial lesions but in most cases electron beam sources are more adequate especially for large and deeper lesions. (author)

  18. On the half-life of luminescence signals in dosimetric applications: A unified presentation

    Science.gov (United States)

    Pagonis, V.; Kitis, G.; Polymeris, G. S.

    2018-06-01

    Luminescence signals from natural and man-made materials are widely used in dosimetric and dating applications. In general, there are two types of half-lives of luminescence signals which are of importance to experimental and modeling work in this research area. The first type of half-life is the time required for the population of the trapped charge in a single trap to decay to half its initial value. The second type of half-life is the time required for the luminescence intensity to drop to half of its initial value. While there a handful of analytical expressions available in the literature for the first type of half-life, there are no corresponding analytical expressions for the second type. In this work new analytical expressions are derived for the half-life of luminescence signals during continuous wave optical stimulation luminescence (CW-OSL) or isothermal luminescence (ITL) experiments. The analytical expressions are derived for several commonly used luminescence models which are based on delocalized transitions involving the conduction band: first and second order kinetics, empirical general order kinetics (GOK), mixed order kinetics (MOK) and the one-trap one-recombination center (OTOR) model. In addition, half-life expressions are derived for a different type of luminescence model, which is based on localized transitions in a random distribution of charges. The new half-life expressions contain two parts. The first part is inversely proportional to the thermal or optical excitation rate, and depends on the experimental conditions and on the cross section of the relevant luminescence process. The second part is characteristic of the optical and/or thermal properties of the material, as expressed by the parameters in the model. A new simple and quick method for analyzing luminescence signals is developed, and examples are given of applying the new method to a variety of dosimetric materials. The new test allows quick determination of whether a set of

  19. Development of a thermally stimulated exoelectron emission (TSEE) system for dosimetric applications

    International Nuclear Information System (INIS)

    Rocha, Felicia del Gallo

    1997-01-01

    A thermally stimulated exoelectron emission measuring system (TSEE) with a counting (reader) and a heating system was designed, constructed and tested for the dosimetry of weakly penetrating radiations, such as alpha and beta particles and low energy X rays. The counting system consists of a 271 windowless gas-flow proportional counter, while the heating system is composed by a temperature programmer that provides linear heating of the samples. The characterization of the proportional counter was done, as well as the tests to verify the performance of the counting system with reference TSEE materials, such as beryllium oxide (BeO) and magnesium oxide (MgO) single crystals. The dosimetric characteristics of some materials as pure calcium sulphate (CaS0 4 ) sintered pellets and with 10% of graphite in its composition, lithium fluoride doped with magnesium, copper and phosphor (LiF:Mg,Cu,P), lithium fluoride (LiF) thin films on aluminum and stainless steel substrates and BeO on graphite substrates were studied. As an application, the feasibility of the use of pure calcium sulphate sintered pellets and others with 10% of graphite in area monitoring of an electron accelerator with variable energy was studied. The obtained results show the usefulness of this system in the dosimetry of weakly penetrating radiations. (author)

  20. Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins

    International Nuclear Information System (INIS)

    Dempsey, James F.; Williams, Jeffery A.; Stubbs, James B.; Patrick, Timothy J.; Williamson, Jeffrey F.

    1998-01-01

    Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor. Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determine the dosimetric characteristics of spherical geometry balloons filled with photon-emitting radionuclide solutions. Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified dose rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional 125 I seed volume implants. Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm. The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with 125 I seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue ''hot spots;'' however, more healthy tissue volume receives a dose of the prescribed dosage or less. Conclusions: This device, when filled with 125 I solution, is suitable for classical LDR treatments and may be preferable to 125 I interstitial

  1. Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P Thermoluminescent Dosemeter and its applications in diagnostic radiology - a review

    Energy Technology Data Exchange (ETDEWEB)

    Fung, K.L. E-mail: orkarl@polyu.edu.hk

    2004-05-01

    This study investigated the dosimetric properties of the high sensitivity TLD (Thermoluminescent Dosemeter) of LiF:Mg,Cu,P and its applications in diagnostic radiology. A reproducible readout and annealing regime for this high sensitivity TLD was developed in the initial part of this study with the newly installed automatic TLD Reader system. Basic dosimetric characteristics of this T.L. dosemeter were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom. The applications studied in radiological procedures included: dose reduction in lumbar spine radiography utilizing the 'anode heel effect'; gonad dose variation with kV{sub p} in chest radiography; foetal dose comparison between computed tomography (CT) and computed radiography (CR) in X-ray pelvimetry; lens dose reduction with bismuth eye-shields in CT brain studies; foetal dose assessment of early pregnancy in common high risk radiological examinations. It is anticipated that the unique and favourable dosimetric performance of LiF:Mg,Cu,P T.L. phosphor will be exploited further in measurements of low level dose received by patients and staff in diagnostic radiological procedures such as paediatric X-ray examinations.

  2. Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P Thermoluminescent Dosemeter and its applications in diagnostic radiology - a review

    International Nuclear Information System (INIS)

    Fung, K.L.

    2004-01-01

    This study investigated the dosimetric properties of the high sensitivity TLD (Thermoluminescent Dosemeter) of LiF:Mg,Cu,P and its applications in diagnostic radiology. A reproducible readout and annealing regime for this high sensitivity TLD was developed in the initial part of this study with the newly installed automatic TLD Reader system. Basic dosimetric characteristics of this T.L. dosemeter were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom. The applications studied in radiological procedures included: dose reduction in lumbar spine radiography utilizing the 'anode heel effect'; gonad dose variation with kV p in chest radiography; foetal dose comparison between computed tomography (CT) and computed radiography (CR) in X-ray pelvimetry; lens dose reduction with bismuth eye-shields in CT brain studies; foetal dose assessment of early pregnancy in common high risk radiological examinations. It is anticipated that the unique and favourable dosimetric performance of LiF:Mg,Cu,P T.L. phosphor will be exploited further in measurements of low level dose received by patients and staff in diagnostic radiological procedures such as paediatric X-ray examinations

  3. Dosimetric evaluation of a novel high dose rate (HDR) intraluminal / interstitial brachytherapy applicator for gastrointestinal and bladder cancers

    Science.gov (United States)

    Aghamiri, Seyyed Mahmoud Reza; Najarian, Siamak; Jaberi, Ramin

    2010-01-01

    High dose rate (HDR) brachytherapy is one of the accepted treatment modalities in gastro‐intestinal tract and bladder carcinomas. Considering the shortcoming of contact brachytherapy routinely used in gastrointestinal tract in treatment of big tumors or invasive method of bladder treatment, an intraluminal applicator with the capability of insertion into the tumor depth seems to be useful. This study presents some dosimetric evaluations to introduce this applicator to the clinical use. The radiation attenuation characteristics of the applicator were evaluated by means of two dosimetric methods including well‐type chamber and radiochromic film. The proposed 110 cm long applicator has a flexible structure made of stainless steel for easy passage through lumens and a needle tip to drill into big tumors. The 2 mm diameter of the applicator is thick enough for source transition, while easy passage through any narrow lumen such as endoscope or cystoscope working channel is ensured. Well‐chamber results showed an acceptably low attenuation of this steel springy applicator. Performing absolute dosimetry resulted in a correlation coefficient of R=0.9916(p‐value≈10−7) between standard interstitial applicator and the one proposed in this article. This study not only introduces a novel applicator with acceptable attenuation but also proves the response independency of the GAFCHROMIC EBT films to energy. By applying the dose response of the applicator in the treatment planning software, it can be used as a new intraluminal / interstitial applicator. PACS number: 87.53.Bn, 87.53.Jw, 29.40.Cs

  4. Dosimetric differences between electrons beams with rio applicators of GMV and conventional Elekta applicators

    International Nuclear Information System (INIS)

    Sendon del Rio, J. R.; Ayala Lazaro, R.; Jimenez Rojas, M. R.; Gomez Cores, S.; Gonzalez Ruiz, C.; Garcia Hernandez, M. J.; Lopez Bote, M. A.

    2013-01-01

    Intraoperative radiotherapy (River) is a form of cancer treatment that consists of a session of radiation ionizing on macroscopic tumor or tumor bed surgically exposed. In our institution, is administered with beams of electrons in a Linear Accelerator for use general and adapted through specific (applicators RIVER). In this work we studied the dosimetry differences between modified by applicators electron beams conventional and they changed by applicators River. (Author)

  5. Dosimetric effects of saline- versus water-filled balloon applicators for IORT using the model S700 electronic brachytherapy source.

    Science.gov (United States)

    Redler, Gage; Templeton, Alistair; Zhen, Heming; Turian, Julius; Bernard, Damian; Chu, James C H; Griem, Katherine L; Liao, Yixiang

    The Xoft Axxent Electronic Brachytherapy System (Xoft, Inc., San Jose, CA) is a viable option for intraoperative radiation therapy (IORT) treatment of early-stage breast cancer. The low-energy (50-kVp) X-ray source simplifies shielding and increases relative biological effectiveness but increases dose distribution sensitivity to medium composition. Treatment planning systems typically assume homogenous water for brachytherapy dose calculations, including precalculated atlas plans for Xoft IORT. However, Xoft recommends saline for balloon applicator filling. This study investigates dosimetric differences due to increased effective atomic number (Z eff ) for saline (Z eff  = 7.56) versus water (Z eff  = 7.42). Balloon applicator diameters range from 3 to 6 cm. Monte Carlo N-Particle software is used to calculate dose at the surface (D s ) of and 1 cm away (D 1cm ) from the water-/saline-filled balloon applicator using a single dwell at the applicator center as a simple estimation of the dosimetry and multiple dwells simulating the clinical dose distributions for the atlas plans. Single-dwell plans show a 4.4-6.1% decrease in D s for the 3- to 6-cm diameter applicators due to the saline. Multidwell plans show similar results: 4.9% and 6.4% D s decrease, for 4-cm and 6-cm diameter applicators, respectively. For the single-dwell plans, D 1cm decreases 3.6-5.2% for the 3- to 6-cm diameter applicators. For the multidwell plans, D 1cm decreases 3.3% and 5.3% for the 4-cm and 6-cm applicators, respectively. The dosimetric effect introduced by saline versus water filling for Xoft balloon applicator-based IORT treatments is ∼5%. Users should be aware of this in the context of both treatment planning and patient outcome studies. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  6. Dosimetric effects of an air cavity for the SAVI partial breast irradiation applicator

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Susan L.; Pino, Ramiro [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, Methodist Hospital, Houston, Texas 77030 and Texas Cancer Clinic, San Antonio, Texas 78240 (United States)

    2010-08-15

    Purpose: To investigate the dosimetric effect of the air inside the SAVI partial breast irradiation device. Methods: The authors have investigated how the air inside the SAVI partial breast irradiation device changes the delivered dose from the homogeneously calculated dose. Measurements were made with the device filled with air and water to allow comparison to a homogenous dose calculation done by the treatment planning system. Measurements were made with an ion chamber, TLDs, and film. Monte Carlo (MC) simulations of the experiment were done using the EGSnrc suite. The MC model was validated by comparing the water-filled calculations to those from a commercial treatment planning system. Results: The magnitude of the dosimetric effect depends on the size of the cavity, the arrangement of sources, and the relative dwell times. For a simple case using only the central catheter of the largest device, MC results indicate that the dose at the prescription point 1 cm away from the air-water boundary is about 9% higher than the homogeneous calculation. Independent measurements in a water phantom with a similar air cavity gave comparable results. MC simulation of a realistic multidwell position plan showed discrepancies of about 5% on average at the prescription point for the largest device. Conclusions: The dosimetric effect of the air cavity is in the range of 3%-9%. Unless a heterogeneous dose calculation algorithm is used, users should be aware of the possibility of small treatment planning dose errors for this device and make modifications to the treatment delivery, if necessary.

  7. A spectrophotometric readout for γ irradiated alanine solution - a dosimetric application

    International Nuclear Information System (INIS)

    Marzouk, Asma

    2007-01-01

    Alanine is a stable dosimeter of reference in its solid state. Its installation in solution as being a dosimetric system of routine remains very useful. A follow-up of the behaviour of the irradiated alanine solution with 15 kGy according to the concentration is carried out by UV-Visible spectrophotometry. The results obtained prove the difficulty in analytical studies of the radiolysis of aqueous solutions by optical absorption due to the ambiguous broad spectra of the species and the reaction products. (Author). 47 refs

  8. The ICRP task group respiratory tract model - an age-dependent dosimetric model for general application

    International Nuclear Information System (INIS)

    Bailey, M.R.; Birchall, A.

    1992-01-01

    The ICRP Task Group on Human Respiratory Tract Models for Radiological Protection has developed a revised dosimetric model for the respiratory tract. Papers outlining the model, and describing each aspect of it were presented at the Third International Workshop on Respiratory Tract Dosimetry (Albuquerque 1-3 July 1990), the Proceedings of which were recently published in Radiation Protection Dosimetry Volume 38 Nos 1-3 (1991). Since the model had not changed substantially since the Workshop at Albuquerque, only a summary of the paper presented at Schloss Elmau is included in these Proceedings. (author)

  9. Synthesis and characterization of CaF{sub 2}:Dy nanophosphor for dosimetric application

    Energy Technology Data Exchange (ETDEWEB)

    Bhadane, Mahesh S.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, University of Pune, Pune-411007 (India); Patil, B. J. [Department of Physics, Abasaheb Garware College, Pune-411004 (India); Kulkarni, M. S. [Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhatt, B. C. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2015-06-24

    In this work, nanoparticles (NPs) of dysprosium doped calcium fluoride (CaF{sub 2}:Dy) 1 mol % has been prepared using simple chemical co-precipitation method and its thermoluminescence (TL) dosimetric properties were studied. The synthesized nanoparticle sample was characterized by X-ray diffraction (XRD) and the particle size of face centered cubic phase NPs was found around 30 nm. The shape, morphology and size were also observed by scanning electron microscopy (SEM). From gamma irradiated CaF{sub 2}:Dy TL curves, it was observed that the total areas of all the glow peak intensities are dramatically changed with increase in annealing temperature. Further, TL glow curve of the CaF{sub 2}:Dy at 183 °C annealed at 400 °C, showed very sharp linear response in the dose range from 1 Gy to 750 Gy. This linear response of CaF{sub 2}:Dy nanophosphor as a function of gamma dose is very useful from radiation dosimetric point of view.

  10. Fast neutron irradiation effects on CR-39 nuclear track detector for dosimetric applications

    International Nuclear Information System (INIS)

    Kader, M.H.

    2005-01-01

    The effect of neutron irradiation on the dosimetric properties of CR-39 solid-state nuclear track detector have been investigated. CR-39 samples were irradiated with neutrons of energies follow a Maxwellian distribution centered about 2 MeV. These samples were irradiated with different doses in the range 0.1-1 Sv. The background and track density were measured as a function of etching time. In addition, the dependence of sensitivity of CR-39 detector on the neutrons dose has been investigated. The results show that the Sensitivity started to increase at 0.4 Sv neutrons dose, so this sample were chosen to be a subject for further study to investigate the effect of gamma dose on its properties. The sample irradiated with 0.4 Sv were exposed to different doses of gamma rays at levels between 10 and 80 kGy. The effect of gamma doses on the bulk etching rate VB, the track diameter and the sensitivity of the CR-39 samples was investigated. The results show that the dosimetric properties of CR-39 SSNTD are greatly affected by both neutron and gamma irradiation

  11. SESAME: a software tool for the numerical dosimetric reconstruction of radiological accidents involving external sources and its application to the accident in Chile in December 2005.

    Science.gov (United States)

    Huet, C; Lemosquet, A; Clairand, I; Rioual, J B; Franck, D; de Carlan, L; Aubineau-Lanièce, I; Bottollier-Depois, J F

    2009-01-01

    Estimating the dose distribution in a victim's body is a relevant indicator in assessing biological damage from exposure in the event of a radiological accident caused by an external source. This dose distribution can be assessed by physical dosimetric reconstruction methods. Physical dosimetric reconstruction can be achieved using experimental or numerical techniques. This article presents the laboratory-developed SESAME--Simulation of External Source Accident with MEdical images--tool specific to dosimetric reconstruction of radiological accidents through numerical simulations which combine voxel geometry and the radiation-material interaction MCNP(X) Monte Carlo computer code. The experimental validation of the tool using a photon field and its application to a radiological accident in Chile in December 2005 are also described.

  12. Evaluation of dosimetric characteristics of graphene oxide/PVC nanocomposite for gamma radiation applications

    Energy Technology Data Exchange (ETDEWEB)

    Feizi, Shahzad; Malekie, Shahryar; Ziaie, Farhood [Nuclear Science and Technology Research Institute (NSTRI), Karaj (Iran, Islamic Republic of). Radiation Application Research School; Rahighi, Reza; Tayyebi, Ahmad [Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Physics

    2017-04-01

    Graphene oxide-polyvinyl chloride composite was prepared using tetrahydrofuran solvent-assisted dispersion of characterized nano flakes of graphene oxide in polymer matrix. Electrical percolation threshold of GO/PVC nanocomposite was determined via a finite element simulation method with a 2D model and compared with experimental results. A conductive cell with two silver coated walls was designed and fabricated for exploring dosimetric properties of the composite. Some characteristics of the new nanocomposite such as linearity of dose response, repeatability, sensitivity and angular dependence are investigated. According to 2D proposed method, obtained data associated to electrical conductivity of the GO/polymer composite for PVC matrix plotted in different GO weight percentages and had good compatibility (validity) with experimental data. The dose response is linear in the 17-51 mGy dose range and it can be introduced for gamma radiation dosimetry in diagnostic activities.

  13. Dosimetric Characteristics of Radio-Photoluminescent Glass Dosimeters for Medical Applications: Linearity

    Energy Technology Data Exchange (ETDEWEB)

    Shehzadi, N. N.; Jeong, J. P.; Kim, B. C.; Kim, I. J.; Yi, C. Y. [Center for Ionizing Radiation, Korea Research Institute of Standards and Science, Seoul (Korea, Republic of)

    2017-04-15

    Radio-photoluminescent glass dosimeter (GD) has advantage of non-destructive reading process, negligible fading and superior radiation detection characteristics than other personal dosimeters like thermoluminescent dosimeters (TLD) or film dosimeters. In this study, one dosimetric characteristic of GDs, dose linearity was evaluated with two different approaches: one for each set of GDs selected and another for a batch of them using accumulated doses of same set of GDs and GDs in a batch, respectively. Within a dose range upto 10 Gy, not only each set of GDs but also a batch of them showed excellent linearity. Within a dose range upto 10 Gy, not only each set of GDs but also a batch of them showed excellent linearity.

  14. Dosimetric characterization of an electronic portal imaging device (EPID) and development of a portal dosimetry simple model; Caracterizacion dosimetrica de un dispositivo electronico de imagen portal (EPID) y desarrollo de un modelo simple de dosimetria portal

    Energy Technology Data Exchange (ETDEWEB)

    Ripol ValentIn, O.; GarcIa Romero, A.; Hernandez Vitoria, A.; Jimenez Albericio, J.; Cortes Rodicio, J.; Millan Cebrian, E.; Ruiz Manzano, P.; Canellas Anoz, M.

    2010-07-01

    The use of the Electronic Portal Imaging Devices (EPID) for the quality control of linear accelerators of electrons is increasingly extended in practice. In this work the dosimetric characteristics of an EPID OptiVue{sup TM}1000 ST were studied and a friendly and simple method for the absorbed dose calibration was suggested. This method is based on a simple mathematical model, including: an absorbed dose transformation coefficient and image lag and field shape corrections. Software tools were developed in order to process the information and the results were validated by comparing them with the measured data with ionization chambers. The studied device showed suitable characteristics for its use for EPID dosimetry and the calculated results fitted satisfactorily with the dose planes obtained with the ionization chambers. Keeping in mind the model limitations, we concluded that it is possible to start the use of the EPID for the accelerator quality control and improvements for the current model should be studied, as well as other suitable applications: e.g. the Intensity Modulated Radiation Therapy (IMRT) treatment verification procedures. (Author).

  15. Application of an EPID for fast daily dosimetric quality control of a fully computer-controlled treatment unit

    International Nuclear Information System (INIS)

    Dirkx, M.L.P.; Kroonwijk, M.; De Boer, J.C.J.; Heijmen, B.J.M.

    1995-01-01

    The MM50 Racetrack Microtron, suited for sophisticated three-dimensional computer-controlled conformal radiotherapy techniques, is a complex treatment unit in various respects. Therefore, for a number of gantry angles, daily quality control of the absolute output and the profiles of the scanned photon beams in mandatory. A fast method for these daily checks, based on dosimetric measurements with the Philips SRI-100 Electronic Portal Imaging Device, has been developed and tested. Open beams are checked for four different gantry angles; for gantry angle 0, a wedged field is checked as well. The fields are set up one after another under full computer control. Performing and analyzing the measurements takes about ten minutes. The applied EPID has favourable characteristics for dosimetric quality control measurements: absolute measurements reproduce within 0.5% (1 SD) and the reproducibility of a relative (2-D) fluence profile is 0.2% (1 SD). The day-to-day sensitivity stability over a period of a month is 0.6% (1 SD). EPID-signals are within 0.2% linear with the applied dose. The 2-D fluence profile of the 25 MV photon beam of the MM50 is very stable in time: during a period of one year, a maximum fluctuation of 2.6% was observed. Once, a deviation in the cGy/MU-value of 6% was detected. Only because of the performed morning quality control checks with the EPID, erroneous dose delivery to patients could be avoided; there is no interlock in the MM50-system that would have prevented patient treatment. Based on our experiences and on clinical requirements regarding the acceptability of deviations of beam characteristics, a protocol has been developed including action levels for additional investigations. Studies on the application of the SRI-100 for in vivo dosimetry on the MM50 have been started

  16. Application of an EPID for fast daily dosimetric quality control of a fully computer-controlled treatment unit

    Energy Technology Data Exchange (ETDEWEB)

    Dirkx, M L.P.; Kroonwijk, M; De Boer, J C.J.; Heijmen, B J.M. [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands)

    1995-12-01

    The MM50 Racetrack Microtron, suited for sophisticated three-dimensional computer-controlled conformal radiotherapy techniques, is a complex treatment unit in various respects. Therefore, for a number of gantry angles, daily quality control of the absolute output and the profiles of the scanned photon beams in mandatory. A fast method for these daily checks, based on dosimetric measurements with the Philips SRI-100 Electronic Portal Imaging Device, has been developed and tested. Open beams are checked for four different gantry angles; for gantry angle 0, a wedged field is checked as well. The fields are set up one after another under full computer control. Performing and analyzing the measurements takes about ten minutes. The applied EPID has favourable characteristics for dosimetric quality control measurements: absolute measurements reproduce within 0.5% (1 SD) and the reproducibility of a relative (2-D) fluence profile is 0.2% (1 SD). The day-to-day sensitivity stability over a period of a month is 0.6% (1 SD). EPID-signals are within 0.2% linear with the applied dose. The 2-D fluence profile of the 25 MV photon beam of the MM50 is very stable in time: during a period of one year, a maximum fluctuation of 2.6% was observed. Once, a deviation in the cGy/MU-value of 6% was detected. Only because of the performed morning quality control checks with the EPID, erroneous dose delivery to patients could be avoided; there is no interlock in the MM50-system that would have prevented patient treatment. Based on our experiences and on clinical requirements regarding the acceptability of deviations of beam characteristics, a protocol has been developed including action levels for additional investigations. Studies on the application of the SRI-100 for in vivo dosimetry on the MM50 have been started.

  17. SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States); Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A [East Carolina University, Greenville, NC (United States); Corbett, M [Greenville Health System, Greenville, SC (United States)

    2016-06-15

    Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

  18. SU-G-201-07: Dosimetric Verification of a 3D Printed HDR Skin Brachytherapy Applicator

    International Nuclear Information System (INIS)

    Rasmussen, K; Stanley, D; Eng, T; Kirby, N; Gutierrez, A; Stathakis, S; Papanikolaou, N; Baumgarten, A; Pelletier, C; Jung, J; Feng, Y; Huang, Z; Ju, A; Corbett, M

    2016-01-01

    Purpose: The use of radiation as a treatment modality for skin cancer has increased significantly over the last decade with standardized applicators. Utilizing 3D printing, the ability to make applicators specifically designed for each patient’s anatomy has become economically feasible. With this in mind it was the aim of this study to determine the dosimetric accuracy of a 3-D printed HDR brachytherapy applicator for the skin. Methods: A CT reference image was used to generate a custom applicator based on an anthropomorphic head and neck phantom. To create the applicator a 1cm expansion anteriorly with 0.5cmX0.5cm trenches on the outer surface that were spaced 1cm sup-inf to accommodate standard 6F flexible catheters. The applicator was printed using PLA material using a printrbot simple printer. A treatment plan optimized to deliver a clinically representative volume was created in Oncentra and delivered with a nucletron afterloader. Measurements were made using TLDs and EBT3 gafchromic film that were placed between the applicator and the phantom’s forehead. An additional piece of film was also used to qualitatively asses the dose distribution in the transverse plane. Using a standard vaginal cylinder and bolus, a standardized curve correlating TLD and film exposure-to-radiation dose was established by irradiating film to known doses (200,500,700 cGy) at a 3.5 cm radius distance. Results: Evaluated TLDs showed the absolute dose delivered to the skin surface using the 3-D printed bolus was 615cGy±6%, with a mean predicted TPS value in the measured area of 617.5±7%. Additionally, planar dose distributions had good qualitative agreement with calculated TPS isodoses. Conclusion: This work demonstrates patient specific 3-D printed HDR brachytherapy applicators for skin cancer treatments are practical and accurate in TPS calculations but additional measurements are needed to verify additional sites and dose at depth.

  19. Potential application of metal nanoparticles for dosimetric systems: Concepts and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder José, E-mail: ederguidelli@pg.ffclrp.usp.br; Baffa, Oswaldo, E-mail: ederguidelli@pg.ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP (Brazil)

    2014-11-07

    Metallic nanoparticles increase the delivered dose and consequently enhance tissue radio sensitization during radiation therapy of cancer. The Dose Enhancement Factor (DEF) corresponds to the ratio between the dose deposited on a tissue containing nanoparticles, and the dose deposited on a tissue without nanoparticles. In this sense, we have used electron spin resonance spectroscopy (ESR) to investigate how silver and gold nanoparticles affect the dose deposition in alanine dosimeters, which act as a surrogate of soft tissue. Besides optimizing radiation absorption by the dosimeter, the optical properties of these metal nanoparticles could also improve light emission from materials employed as radiation detectors. Therefore, we have also examined how the plasmonic properties of noble metal nanoparticles could enhance radiation detection using optically stimulated luminescence (OSL) dosimetry. This work will show results on how the use of gold and silver nanoparticles are beneficial for the ESR and OSL dosimetric techniques, and will describe the difficulties we have been facing, the challenges to overcome, and the perspectives.

  20. EPR dosimetric properties of 2-methylalanine pellet for radiation processing application

    International Nuclear Information System (INIS)

    Soliman, Y.S.; Ali, Laila I.; Moustafa, H.; Tadros, Soad M.

    2014-01-01

    The dosimetric characteristics of γ-radiation induced free radicals in 2-methylalanine (2MA) pellet dosimeter are investigated using electron paramagnetic resonance (EPR) in the high-dose range of 1–100 kGy. The EPR spectrum of γ-irradiated 2MA exhibits an isotropic EPR signal with seven lines. The dosimeter response is humidity independent in the range of 33–76% relative humidity. The manufactured dosimeter is typically adipose tissue equivalent in the energy level of 0.1–15 MeV. The overall uncertainty (2σ) of the dosimeter is less than 6.9%. - Highlights: • Preparation of 2-methyl alanine pellets for high-dose dosimetry (1–100 kGy). • The dosimeter response is humidity independent in 33–76% relative humidity range during irradiation. • The temperature coefficient equals 0.96%/°C in the range of 21–60 °C. • Overall uncertainty of the dosimeter not exceeds 6.9% at 2σ

  1. Dosimetric properties of textile fibers: application of electron paramagnetic resonance dosimetry to an accidental gamma irradiation

    International Nuclear Information System (INIS)

    Kamenopoulou, V.

    1988-01-01

    The dosimetric properties of some twenty textile fibers have been studied in order to develop a method for determining the dose received in the case of an accidental gamma irradiation. Three textile fibers having properties most closely satisfying our needs were selected for detailed investigations: cotton, polypropylene and quartz. Electron Paramagnetic Resonance (EPR) readout techniques were used. In order to eliminate spectral anisotropy problems due to textile fiber inhomogeneities, a system has been developed to rotate samples in the resonant cavity during measurements. The structure, physical and chemical properties of cotton and polypropylene were investigated. A bibliographic study of the combined effects of light, heat and ionizing radiation on textile fibers was carried out. A linear relation exists between the EPR signal and the gamma ray dose received over a certain dose range. A method has been developed for preparing samples so as to reduce background noise not due to irradiation; in this way the detection threshold is lowered and a greater time stability obtained. Unknown doses corresponding to known spectra are determined by linear interpolation using a series of spectra obtained from the same fabric irradiated with known doses [fr

  2. BeOSL system for personal dosimetry : dosimetric characteristics and practical application

    International Nuclear Information System (INIS)

    Mende, E.

    2015-10-01

    Full text: BeOSL system of Dosimetric s is very easy to use, assimilate and maintain. Our dosimeter defines a milestone in the supervision of personal equivalent dose of Hp (10) and Hp (0.07) it covers the range of total energy of 16 KeV to 10 MeV. For this energy range is exceptional in its energy dependence for official personal dosimetry. The BeOSL system consists of two modules, one of them is the BeOSL reader that measures the radiation exposure using the latest technology, optically stimulated luminescence (OSL). The reading is extremely fast; it does not require consumables such as nitrogen or other. The detector material is beryllium oxide (Be O); this is an OSL material tissue equivalent and therefore is ideal for personal dosimetry. The BeOSL technology allows multiple readings of the dosimeter (re-read) to verify the dose or archive the dosimeter. One of the biggest advantages of BeOSL system is its modular concept allows the system to run as a manual solution or as a complete automated robotic system, which can be filled with up to 5,000 dosimeters as bulk cargo. (Author)

  3. Dosimetric characteristics of aqueous solution of crystal violet for applications in food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Khan, H M; Naz, Shagufta; Tabassum, Safia [Peshawar University, Peshawar (Pakistan). Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry

    2011-07-15

    Aqueous solution of crystal violet has been evaluated spectrophotometrically as a gamma-ray chemical dosimeter. The response of the chemical dosimetric system has also been investigated under different environmental conditions, such as light and temperature. In the present study the response has been measured at two wavelengths; 588 nm ({lambda}{sub max} of the irradiated solution) and 500 nm. The response of the crystal violet dosimeter was linear in the dose range of 50-550 Gy at pH 5.6 when absorption measurements were made at 588 and 500 nm. The response of the crystal violet dosimeter during post-irradiation storage at room temperature in dark showed slight decrease in absorbance at 588 and 510 nm but the response was almost stable at 460 nm. For higher doses, the change in the response was greater as compared to the low doses. Post-irradiation stability during diffused sunlight showed significant decrease in the response for higher dose at 588 and 510 nm and slower decrease in the response for lower dose at the above mentioned wavelengths. However the response was almost stable up to 97 days at 460 nm for higher and lower doses. At 4 deg C, the decrease in the absorbance was slower at 588 and 510 nm while the response was almost constant at 460 nm. At higher temperatures, such as 40 deg C, the decrease in the absorbance was greater at 588 and 510 nm while at 460 nm the absorbance was almost constant for about 3 months. (author)

  4. Dosimetric characteristics of aqueous solution of crystal violet for applications in food irradiation

    International Nuclear Information System (INIS)

    Khan, H.M.; Shagufta Naz; Safia Tabassum

    2011-01-01

    Aqueous solution of crystal violet has been evaluated spectrophotometrically as a gamma-ray chemical dosimeter. The response of the chemical dosimetric system has also been investigated under different environmental conditions, such as light and temperature. In the present study the response has been measured at two wavelengths; 588 nm (λ max of the irradiated solution) and 500 nm. The response of the crystal violet dosimeter was linear in the dose range of 50-550 Gy at pH 5.6 when absorption measurements were made at 588 and 500 nm. The response of the crystal violet dosimeter during post-irradiation storage at room temperature in dark showed slight decrease in absorbance at 588 and 510 nm but the response was almost stable at 460 nm. For higher doses, the change in the response was greater as compared to the low doses. Post-irradiation stability during diffused sunlight showed significant decrease in the response for higher dose at 588 and 510 nm and slower decrease in the response for lower dose at the above mentioned wavelengths. However the response was almost stable up to 97 days at 460 nm for higher and lower doses. At 4 deg C, the decrease in the absorbance was slower at 588 and 510 nm while the response was almost constant at 460 nm. At higher temperatures, such as 40 deg C, the decrease in the absorbance was greater at 588 and 510 nm while at 460 nm the absorbance was almost constant for about 3 months. (author)

  5. SU-E-T-10: A Clinical Implementation and the Dosimetric Evidence in High Dose Rate Vaginal Multichannel Applicator Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Syh, J; Patel, B; Zhang, J; Wu, H; Rosen, L [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2015-06-15

    Purpose: The multichannel cylindrical applicator has a distinctive modification of the traditional single channel cylindrical applicator. The novel multichannel applicator has additional peripheral channels that provide more flexibility both in treatment planning process and outcomes. To protect by reducing doses to adjacent organ at risk (OAR) while maintaining target coverage with inverse plan optimization are the goals for such novel Brachytherapy device. Through a series of comparison and analysis of reults in more than forty patients who received HDR Brachytherapy using multichannel vaginal applicator, this procedure has been implemented in our institution. Methods: Multichannel planning was CT image based. The CTV of 5mm vaginal cuff rind with prescribed length was well reconstructed as well as bladder and rectum. At least D95 of CTV coverage is 95% of prescribed dose. Multichannel inverse plan optimization algorithm not only shapes target dose cloud but set dose avoids to OAR’s exclusively. The doses of D2cc, D5cc and D5; volume of V2Gy in OAR’s were selected to compare with single channel results when sole central channel is only possibility. Results: Study demonstrates plan superiorly in OAR’s doe reduction in multi-channel plan. The D2cc of the rectum and bladder were showing a little lower for multichannel vs. single channel. The V2Gy of the rectum was 93.72% vs. 83.79% (p=0.007) for single channel vs. multichannel respectively. Absolute reduced mean dose of D5 by multichannel was 17 cGy (s.d.=6.4) and 44 cGy (s.d.=15.2) in bladder and rectum respectively. Conclusion: The optimization solution in multichannel was to maintain D95 CTV coverage while reducing the dose to OAR’s. Dosimetric advantage in sparing critical organs by using a multichannel applicator in HDR Brachytherapy treatment of the vaginal cuff is so promising and has been implemented clinically.

  6. Study of the synthesis method and stability response of the doped poly aniline used for dosimetric applications

    International Nuclear Information System (INIS)

    Pacheco, Ana P.L.; Araujo, Elmo S.; Azevedo, Walter M. de

    2002-01-01

    Preliminary studies indicated that PANI is a suitable material for the use in the dosimetry area. Experimental results indicate that the conductivity properties of the polymer is affected by the absorbed dose. In that reason it is possible to quantify the dose, analyzing the variation of the electrical resistance of the polymer as a function of the dose. However, to use this material in the dosimetry area it is necessary to studies the response stability of the material along the time, before and after the irradiation. In this work we will show the study of the stability behavior of PANI, during its life time. For that we will use films of doped PANI, synthesized by different methodologies and conditioned in different temperature and humidity conditions. This study is important because we can define which is the best synthesis method to produce PANI films that can be used for making devices to be used in dosimetric applications, as well as, the best conditions those devices should be conditioned before its irradiation. (author)

  7. Dosimetric evaluation of semiconductor detectors for application in neutron dosimetry and microdosimetry in nuclear reactor and radiosurgical facilities

    International Nuclear Information System (INIS)

    Cardenas, Jose Patricio Nahuel

    2010-01-01

    The main objective of this research is the dosimetric evaluation of semiconductor components (surface barrier detectors and PIN photodiodes) for applications in dose equivalent measurements on low dose fields (fast and thermal fluxes) using an AmBe neutron source, the IEA-R1 reactor neutrongraphy facility (epithermal and thermal fluxes) and the Critical Unit facility IPEN/MB-01 (fast fluxes). As moderator compound to fast neutrons flux from the AmBe source was used paraffin and boron and polyethylene as converter for thermal and fast neutrons measurements. The resulting fluxes were used to the irradiation of semiconductor components (SSB - Surface Barrier Detector and PIN photodiodes). A mixed converter made of a borated polyethylene foil (Kodak) was also used. Monte Carlo simulation methodology was employed to evaluate analytically the optimal paraffin thickness. The obtained results were similar to the experimental data and allowed the evaluation of emerging neutron flux from moderator, as well as the fast neutron flux reaching the polyethylene covering the semiconductor sensitive surface. Gamma radiation levels were evaluated covering the whole detector with cadmium foil 1 mm thick, allowing thermal neutrons blockage and gamma radiation measurements. The IPEN/MB-01 facility was employed to evaluate the detector response for high neutron flux. The results were in good agreement with other studies published. Using the obtained spectra an approach to dose equivalent calculation was established. (author)

  8. Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P thermoluminescent dosemeter and its applications in diagnostic radiology

    Energy Technology Data Exchange (ETDEWEB)

    Fung, K.K.L

    2000-12-01

    The recent introduction and development of the thermoluminescent (T.L.) phosphor material LiF:Mg,Cu,P (usually named TLD100H or GR200A) has aroused intense interest of scientists in the field of radiation dosimetry due to its very favourable dosimetric characteristics. Both conventional LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P T.L. phosphors are tissue-equivalent but GR200A outperforms in respect of its very much higher sensitivity, by a factor of greater than 25, and a dose detection threshold of less than 1 {mu}Gy. A reproducible readout and annealing regime was developed in the initial part of this study with the newly installed automatic TLD (Thermoluminescence Dosimetry) apparatus in the X-ray and Radiation Physics Laboratories of the Hong Kong Polytechnic University. Basic dosimetric characteristics of this T.L. dosemeter (supplied by Harshaw-Bicron Co.) were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. Dosimetric characteristics which included linearity, reproducibility, batch uniformity, energy response, and minimum detectable dose were studied using X-rays in the commonly used diagnostic radiology energy range. Favourable dosimetric characteristics were observed from this T.L. phosphor, which agrees well with published studies. The effect of the number of thermal treatment cycles in the initialisation process on dosimetric properties of this T.L. phosphor was also investigated. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom using facilities both in these laboratories and also in radiology departments of various district hospitals in Hong Kong. Radiation absorbed dose from the direct or scattered beam, at critical sites inside and on the surface of the phantom, were measured in these radiological studies. The special focus in some of these studies was to

  9. Investigation of dosimetric characteristics of the high sensitivity LiF:Mg,Cu,P thermoluminescent dosemeter and its applications in diagnostic radiology

    International Nuclear Information System (INIS)

    Fung, K.K.L.

    2000-12-01

    The recent introduction and development of the thermoluminescent (T.L.) phosphor material LiF:Mg,Cu,P (usually named TLD100H or GR200A) has aroused intense interest of scientists in the field of radiation dosimetry due to its very favourable dosimetric characteristics. Both conventional LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P T.L. phosphors are tissue-equivalent but GR200A outperforms in respect of its very much higher sensitivity, by a factor of greater than 25, and a dose detection threshold of less than 1 μGy. A reproducible readout and annealing regime was developed in the initial part of this study with the newly installed automatic TLD (Thermoluminescence Dosimetry) apparatus in the X-ray and Radiation Physics Laboratories of the Hong Kong Polytechnic University. Basic dosimetric characteristics of this T.L. dosemeter (supplied by Harshaw-Bicron Co.) were then investigated. This paved the foundation for subsequent selected novel application studies in diagnostic radiology. Dosimetric characteristics which included linearity, reproducibility, batch uniformity, energy response, and minimum detectable dose were studied using X-rays in the commonly used diagnostic radiology energy range. Favourable dosimetric characteristics were observed from this T.L. phosphor, which agrees well with published studies. The effect of the number of thermal treatment cycles in the initialisation process on dosimetric properties of this T.L. phosphor was also investigated. This study exploits the favourable dosimetric properties of these T.L. dosemeters in some selected novel dosimetric applications in diagnostic radiology with an anthropomorphic phantom using facilities both in these laboratories and also in radiology departments of various district hospitals in Hong Kong. Radiation absorbed dose from the direct or scattered beam, at critical sites inside and on the surface of the phantom, were measured in these radiological studies. The special focus in some of these studies was to

  10. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry

    International Nuclear Information System (INIS)

    Mangueira, Thyago Fressatti

    2009-01-01

    In this work the main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a neutron field were also evaluated for the research in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometric. For the clinical field, the intra and inter-batch reproducibility are better than 1.4% and 5.1 %, respectively, the response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h period and the behavior of the dose-response curve of the FXG using the variation in the absorbance relative to the non-irradiated dosimeter as a basis during the whole studied period were not altered. The dose-response to the industrial electron beam presented an exponential decreasing behavior and the neutron beam for research in BNCT presented a linear behavior for the complete studied dose range. According to the obtained results for the different types of radiation studied for the FXG, there was no change in the position of the characteristic bands of the absorption spectrum due to the interaction of these radiation types. Additional tests were performed to determine the digital photographic imaging of FXG analyses viability and the application of FXG dosimetry on intracavitary brachytherapy. The good performance of the FXG dosimeter in the tests that were carried out indicates that this dosimeter may be applied to the tri-dimensional dose evaluation in radiotherapic treatments using electrons and neutron beams. (author)

  11. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    International Nuclear Information System (INIS)

    Reyes-Rivera, E.; Sosa, M.; Reyes, U.; Jesús Bernal-Alvarado, José de; Córdova, T.; Gil-Villegas, A.; Monzón, E.

    2014-01-01

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy

  12. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Rivera, E., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Sosa, M., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Reyes, U., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Jesús Bernal-Alvarado, José de, E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Córdova, T., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Gil-Villegas, A., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx [División de Ciencias e Ingenierías, Universidad de Guanajuato, 37150 León, Gto. (Mexico); Monzón, E., E-mail: emonzon@imss.gob.mx [Unidad de Alta Especialidad No.1, Instituto Mexicano del Seguro Social, Léon, Gto. (Mexico)

    2014-11-07

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy.

  13. Dosimetric Comparison of 3-Dimensional Planning Techniques Using an Intravaginal Multichannel Balloon Applicator for High-Dose-Rate Gynecologic Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-June, E-mail: spark@mednet.ucla.edu; Chung, Melody; Demanes, D. Jeffrey; Banerjee, Robyn; Steinberg, Michael; Kamrava, Mitchell

    2013-11-15

    Purpose: To study the dosimetric differences of various channel combinations of the Capri vaginal applicator. Methods and Materials: The Capri consists of a single central channel (R1), an inner array of 6 channels (R2), and an outer array of 6 channels (R3). Three-dimensional plans were simulated for 6 channel arrangements (R1, R2, R12, R13, R23, and R123). Treatment plans were optimized to the applicator surface or 5-mm depth while minimizing dose to organs at risk (OARs: bladder, rectum, sigmoid, and urethra). The clinical target volume (CTV) was defined as a 5-mm circumferential shell extending 4 cm in length around the applicator. Clinical target volume coverage (D{sub mean}, D{sub 90}, V{sub 100}, and V{sub 150}) and OAR doses (D{sub 0.1} {sub cm{sup 3}}, D{sub 1} {sub cm{sup 3}}, D{sub 2} {sub cm{sup 3}}, and D{sub mean}) were compared. A comparison between the Capri (R123) and a conventional single-channel applicator was also done. Statistical significance (P value <.05) was evaluated with a 2-tailed t test. Results: When prescribing to 5-mm depth, CTV coverage using all 13 channels (R123) versus a single channel (R1) was similar; however, when prescribing to the surface there were differences (P<.0001) in all CTV metrics except for the V{sub 150}. The R1 plans had higher doses to all OARs compared with R123 plans (P<.007). Doses to OARs were not significantly different between R23 and R123 plans (P=.05-.95), and CTV coverage differences were on the order of 1%. Capri R123 plans provided slightly lower CTV D{sub 90} and D{sub mean} but equivalent OAR doses with smaller standard deviations compared with conventional cylinder plans for both prescriptions. Conclusions: The Capri multichannel applicator provides equivalent target coverage at 5-mm depth, with significantly reduced dose to OARs relative to using a single channel. Optimal plans can be achieved using R12 (lowest V{sub 150}) or R123 or R23 (lowest OAR doses)

  14. Development of an application for the home acquisition of dosimetric data in patients with differentiated thyroid cancer undergoing "1"3"1I therapy

    International Nuclear Information System (INIS)

    Contardi, M.; Namías, M.

    2017-01-01

    Objective: To develop an application under the Android mobile operating system, which, together with a miniature solid-state detector, allows obtaining the necessary dosimetric data for estimation of absorbed dose in blood / marrow in patients treated with "1"3"1I. It is expected that from the development of this application can be counted on a greater amount of information on the doses received in blood / marrow by the patients and in this way help to establish better dose-effect correlations. (authors) [es

  15. Characteristic dosimetric as of the material thermoluminescent LIF:Mg, Cu, and P for their use in sanitary applications

    International Nuclear Information System (INIS)

    Ginjaume, M.; Ortega, X.; Duch, M.A.; Sanchez-Reyes, A.

    1998-01-01

    This work presents the characteristics dosimetric of the LiF:Mg, Cu, P obtained for its use in the sanitary field, fundamentally in radiotherapy. The analyzed parameters are sensitivity, reproducibility of the measures, limit inferior of detection, answer energy, linearity of the answer in function of the received dose and the influence of the temperature in the material

  16. Application of a Monte Carlo Penelope code at diverse dosimetric problems in radiotherapy

    International Nuclear Information System (INIS)

    Sanchez, R.A.; Fernandez V, J.M.; Salvat, F.

    1998-01-01

    In the present communication it is presented the results of the simulation utilizing the Penelope code (Penetration and Energy loss of Positrons and Electrons) in several applications of radiotherapy which can be the radioactive sources simulation: 192 Ir, 125 I, 106 Ru or the electron beams simulation of a linear accelerator Siemens KDS. The simulations presented in this communication have been on computers of type Pentium PC of 100 throughout 300 MHz, and the times of execution were from some hours until several days depending of the complexity of the problem. It is concluded that Penelope is a very useful tool for the Monte Carlo calculations due to its great ability and its relative handling facilities. (Author)

  17. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R [University of Kansas Hospital, Kansas City, KS (United States)

    2015-06-15

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators.

  18. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    International Nuclear Information System (INIS)

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R

    2015-01-01

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators

  19. Pelvic MRI application to the dosimetric analysis in Brachytherapy of Uterine Cervix Carcinoma

    International Nuclear Information System (INIS)

    Ahn, S. J.; Chung, W. K.; Nah, B. K.

    1997-01-01

    Before we report the results of curative radiotherapy in cervix cancer patients, we review the significance and safety of our dose specification methods in the brachytherapy system to have the insight of the potential predictive value of doses at specific points. We analyze the 45 cases of cervix cancer patients treated with intracavitary brachytherapy. In the lateral simulation film we draw the isodose curve and observe the absorbed dose rate of point A, the reference point of bladder(SBD) and rectum(SRD). In the sagittal view of pelvic MRI film we demarcate the tumor volume(TV) and determine whether the prescription dose curve of point A covers the tumor volume adequately by drawing the isodose curve as correctly as possible. Also we estimate the maximum point dose of bladder (MBD) and rectum (MRD) and calculate the inclusion area where the absorbed dose rate is higher than that of point A in the bladder (HBV) and rectum (HRV), respectively. Of forty-five cases, the isodose curve of point A seems to cover tumor volume optimally in only 24 (53%). The optimal tumor coverage seems to be associated not with the stage of the disease but with the tumor volume. There is no statistically significant association between SBD/SRD and MBD/MRD, respectively. SRD has statistically significant association with HBV and HRV. Our current treatment calculation methods seem to have the defect in the aspects of the nonoptimal coverage of the bulky tumor and the inappropriate estimation of bladder dose. We therefore need to modify the applicator geometry to optimize the dose distribution at the position of lower tandem source. Also it appears that the position of the bladder in relation to the applicators needs to be defined individually to define 'hot spots'. (author)

  20. SU-E-T-322: A Dosimetric Comparison of PBI Brachytherapy Techniques: SAVI, Contura, and Tube and Button Applicators.

    Science.gov (United States)

    Park, S; Kamrava, M; Demanes, J

    2012-06-01

    To evaluate the dosimetry of partial breast irradiation brachytherapy techniques using the Strut Adjusted Volume Implant (SAVI), Contura, and Tube and Button (T&B) applicators. A total of 51 breast-cancer patients (23 SAVI, 6 Contura, and 22 T&B) were treated. The target was delineated following NSABP B-39 guidelines. 3D plans were optimized using the Inverse Planning Simulated Annealing algorithm to deliver 3.4 Gy per fraction to the target and minimize dose to organs at risk (OARs). Graphical optimization was then used to fine tune the final dose distribution. The minimum cavity-to-skin distance was measured. Target coverage (V90 and V95) and maximum dose (D0.1cc) to the OARs were evaluated. Dose homogeneity index (DHI = 1-V150/V100) was calculated. The average cavity-to-skin distances were 4.1 mm (0.5-9.6 mm, SAVI) and 11.7 mm (7.1-15.4 mm, Contura). The target-to-skin distance for the T&B cases was 8.7 mm (5.0-13.7 mm). The average V90 and V95 to the target were 96.8% and 94.5% (SAVI), 97.0% and 93.0% (Contura), 98.6% and 97.3% (T&B). The mean D0.1cc to the skin, ribs, and lung was 91.5%, 58.8%, 44.5% (SAVI), 93.1%, 51.3%, 40.5% (Contura), 69.1%, 41.5%, and 31.9% (T&B). The average V150 and V200 to the normal breast tissue were 30.4 cc and 14.9 cc (SAVI), 29.5 cc and 7.3 cc (Contura), 18.3 cc and 7.1 cc (T&B). The average DHI for the SAVI, Contura, and T&B cases was 0.55 (0.50-0.60), 0.70 (0.63-0.78), and 0.76 (0.74-0.79). All techniques provided clinically acceptable target coverage and dose to the OARs. The SAVI device provided a lower skin dose at close cavity-to-skin distances while providing excellent target coverage. However, the T&B and Contura applicators produced more homogeneous dose distribution (higher DHI) in the target than the SAVI. The correlations between dosimetric properties and follow-up mammogram results are under investigation. © 2012 American Association of Physicists in Medicine.

  1. Desarrollo rural vs. desarrollo local

    Directory of Open Access Journals (Sweden)

    Gómez Moreno, M.ª Luisa

    2011-06-01

    Full Text Available The subject of this paper is the discussion about the concepts of rural development and local development starting from the different lines that tend in their making up: the Geographic epistemology, the politics based on them and the material processes of development. The issues of this discussion are: the difficulty of reflect this development processes in quantitative evidences (indicators due to their rather qualitative character; the ambiguous definition of their scale, and related to that, their condition spread or concentrated; their suitability to make compatible objectives of both territorial and social cohesion; the limitations to be extrapolated the concept of stakeholders, own of local development, to rural development; the lack of coordination between economic planning and urban planning to the detriment of a true sustainability and, in the opposite, the threats that are to the rural space the application of sustainability politics designed from the urban context.

    El objeto de este artículo es la discusión de los conceptos de desarrollo rural y local a partir de las distintas líneas que convergen en su definición: las elaboraciones epistemológicas de la Geografía, los instrumentos de planificación en ellos basados y los procesos reales. Los términos de esta discusión son los siguientes: La dificultad de expresar en indicadores los resultados de estos procesos de desarrollo, dado su carácter más cualitativo que cuantitativo; la ambigua definición de su escala, y, en relación con ello, su carácter difuso o concentrado; su idoneidad para compatibilizar objetivos de cohesión social y territorial; las limitaciones de la extrapolación al desarrollo rural del concepto de «actores» propio del desarrollo local; la carencia de coordinación entre planificación económica y urbana en detrimento de una sostenibilidad real y, a la inversa, las amenazas para el espacio rural derivadas de la aplicación de políticas de

  2. Dosimetric characterization and identification of TL defect centres in sand for its application in sludge irradiators as an in situ dosimeter

    International Nuclear Information System (INIS)

    Benny, P.G.; Shah, M.R.; Sabharwal, S.; Bhatt, B.C.; Gundu Rao, T.K.

    2003-08-01

    The report presents investigations that have been carried out to establish a method for the routine/ periodic dosimetry for Sludge Hygienisation Research Irradiator (SHRI) facility set up at Baroda (India) for disinfection of liquid sewage sludge in bulk quantity. For this purpose, the possibility of using the sand, one of the components of inorganic matter found in sewage sludge, directly as a TL dosimeter has been explored. The report is presented in two parts. Part 1 presents dosimetric characterization of sand for its application as an in situ dosimeter. A review on various sewage sludge irradiators operating in the world and the different dosimetric techniques used for these facilities are briefly described. In the present studies, in order to investigate the thermoluminescence properties of sand, it was separated from the sewage sludge by an extensive cleaning procedure. Part 1 also describes the procedure for separation of sand from sewage sludge, study on its TL properties, dosimetric characterization of sand and application of cleaned sand collected at the outlet of the SHRI facility for estimating radiation absorbed dose imparted to the sludge during its disinfection as well as for determining distribution of dose for an irradiated sludge batch. A new method by using phototransferred thermoluminescence (PTTL) in quartz separated from sand has been explored for high-level gamma dosimetry. Part 2 of the report presents sensitization properties of TL peaks and study of TL defect centres in quartz. It describes the results on pre-dose sensitization of 220 degC and 110 degC TL peaks in the quartz samples separated from sand. From the TL and ESR studies, a mechanism for TL sensitization has been suggested, which involves the role of competing traps and E I - centres in the sensitization process. The paramagnetic radicals formed in quartz samples after gamma irradiation by using ESR technique have been briefly described. (author)

  3. Applicability and dosimetric impact of ultrasound-based preplanning in high-dose-rate brachytherapy of prostate cancer

    International Nuclear Information System (INIS)

    Aebersold, D.M.; Isaak, B.; Behrensmeier, F.; Kolotas, C.; Mini, R.; Greiner, R.H.; Thalmann, G.; Kranzbuehler, H.

    2004-01-01

    Background and purpose: analyses of permanent brachytherapy seed implants of the prostate have demonstrated that the use of a preplan may lead to a considerable decrease of dosimetric implant quality. The authors aimed to determine whether the same drawbacks of preplanning also apply to high-dose-rate (HDR) brachytherapy. Patients and methods: 15 patients who underwent two separate HDR brachytherapy implants in addition to external-beam radiation therapy for advanced prostate cancer were analyzed. A pretherapeutic transrectal ultrasound was performed in all patients to generate a preplan for the first brachytherapy implant. For the second brachytherapy, a subset of patients were treated by preplans based on the ultrasound from the first brachytherapy implant. Preplans were compared with the respective postplans assessing the following parameters: coverage index, minimum target dose, homogeneity index, and dose exposure of organs at risk. The prostate geometries (volume, width, height, length) were compared as well. Results: at the first brachytherapy, the matching between the preplan and actual implant geometry was sufficient in 47% of the patients, and the preplan could be applied. The dosimetric implant quality decreased considerably: the mean coverage differed by -0.11, the mean minimum target dose by -0.15, the mean homogeneity index by -0.09. The exposure of organs at risk was not substantially altered. At the second brachytherapy, all patients could be treated by the preplan; the differences between the implant quality parameters were less pronounced. The changes of prostate geometry between preplans and postplans were considerable, the differences in volume ranging from -8.0 to 13.8 cm 3 and in dimensions (width, height, length) from -1.1 to 1.0 cm. Conclusion: preplanning in HDR brachytherapy of the prostate is associated with a substantial decrease of dosimetric implant quality, when the preplan is based on a pretherapeutic ultrasound. The implant quality

  4. Application of the dosimetric model described by Humm to target 131I monoclonal antibodies to leukaemic cells in the cerebrospinal fluid

    International Nuclear Information System (INIS)

    Papanastassiou, V.; Pizer, B.L.; Kemshead, J.T.

    1993-01-01

    In 1986 Humm suggested a dosimetric model for targeted radiation therapy that considered both the physical characteristics of the radionuclide used and the morphology of the targeted tumour. Using this model he described the dose advantage due to antibody binding in terms of a ratio of tumour radiation dose to that of normal tissue. The model applied to non-solid tumours assumes no cell clumping and hence no cross-fire effect. The authors demonstrate the direct application of the model to a particular clinical scenario; the targeting of 131 I monoclonal antibodies to leukaemic cells within the cerebrospinal fluid (CSF). In this situation the dose advantage is much higher than the figure reported by Humm, which was arrived at by considering a more general application of the model. (author)

  5. SU-F-T-30: Comprehensive Dosimetric Characterization of the Novel Direction Modulation Brachytherapy (DMBT) Tandem Applicator Using Monte Carlo Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Safigholi, H; Mashouf, S; Soliman, Abraam; Owrangi, A; Song, W Y [Deprtment of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Han, D [Deprtment of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON (Canada); Department of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States)

    2016-06-15

    Purpose: To characterize the dosimetric properties/distributions of the novel proposed direction modulated brachytherapy (DMBT) tandem applicator in combination with 192Ir HDR source, and compare against conventional tandem design, using Monte Carlo simulations. Methods: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy, especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18.0 g/cc, capable of generating directional dose profiles – leading to enhanced dose sculpting capacity through inverse planning. In-water dosimetric parameters for the DMBT and conventional tandems have been calculated for various radial distances away and around the tandems. For the DMBT tandem, the cumulative dose from the 192Ir source occupying 1) one and 2) all six holes in equal dwell times was calculated and normalized to match the dose rate of the open source (in conventional tandem) at 1 cm from the center. This is done to compare and contrast the characteristic dose distributions to that of the isotropic TG43-based 192Ir source. Results: All dose rates were normalized at 1-cm radius from the center of the applicators, containing source(s). The normalized dose rates at 0.5, 3.0, and 5.0-cm radiuses were then 388, 11.3, and 4.1% for conventional tandem, 657, 8.1, and 2.7% for DMBT tandem with the source in one hole at front entrance, and 436, 10.9, and 3.8% for DMBT tandem with the source in all six holes. For the DMBT tandem case with the source in one hole, the backside transmissions were 47, 2.4, and 0.9%, respectively. Conclusion: The DMBT tandem is able to generate closely similar dosimetric characteristics as that of the single-channel conventional tandem if needed (with the source occupying all six holes), at the same time, generate directional radiation profile(s) for favorably enabling 3D dose sculpting capability.

  6. Development of a Web application for a real time information system; Desarrollo de una aplicacion web para un sistema de informacion en tiempo real

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa R, Alfredo; Silva F, Brisa M; Quintero R, Agustin [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-07-01

    In this article its is described a technique for the development of a Web application for a real time information system that allows the remote and concurrent connection of different equipment to the network historical data base of the system, without the need of the installation of any software component in the remote equipment of the user who makes the consultation. It defines and establishes the software architecture that allows the development of the Web application, the analysis stages, the operation of the technology to be used, as well as the design, development and implementation of the application. Finally, the accomplishments obtained with the development of the Web application for a real time information system are described. [Spanish] En este articulo se describe una tecnica para el desarrollo de una aplicacion web para un sistema de informacion en tiempo real, que permita la conexion remota y concurrente de diferentes equipos en la red a la base de datos historica del sistema, sin necesidad de que se instale ningun componente de software en el equipo remoto del usuario que realiza la consulta. Se define y establece la arquitectura de software que permite el desarrollo de la aplicacion web, las etapas de analisis, el funcionamiento de la tecnologia a utilizar, asi como el diseno, desarrollo e implementacion de la aplicacion. Finalmente, se describen los logros obtenidos con el desarrollo de la aplicacion web para un sistema de informacion en tiempo real.

  7. Evolution of dosimetric phantoms

    International Nuclear Information System (INIS)

    Reddy, A.R.

    2010-01-01

    In this oration evolution of the dosimetric phantoms for radiation protection and for medical use is briefly reviewed. Some details of the development of Indian Reference Phantom for internal dose estimation are also presented

  8. Dosimetric considerations and early clinical experience of accelerated partial breast irradiation using multi-lumen applicators in the setting of breast augmentation

    Science.gov (United States)

    Akhtari, Mani; Pino, Ramiro; Scarboro, Sarah B.; Bass, Barbara L.; Miltenburg, Darlene M.; Butler, E. Brian

    2015-01-01

    Purpose Accelerated partial breast irradiation (APBI) is an accepted treatment option in breast-conserving therapy for early stage breast cancer. However, data regarding outcomes of patients treated with multi-lumen catheter systems who have existing breast implants is limited. The purpose of this study was to report treatment parameters, outcomes, and possible dosimetric correlation with cosmetic outcome for this population of patients at our institution. Material and methods We report the treatment and outcome of seven consecutive patients with existing breast implants and early stage breast cancer who were treated between 2009 and 2013 using APBI following lumpectomy. All patients were treated twice per day for five days to a total dose of 34 Gy using a high-dose-rate 192Ir source. Cosmetic outcomes were evaluated using the Harvard breast cosmesis scale, and late toxicities were reported using the Radiation Therapy Oncology Group (RTOG) late radiation morbidity schema. Results After a mean follow-up of 32 months, all patients have remained cancer free. Six out of seven patients had an excellent or good cosmetic outcome. There were no grade 3 or 4 late toxicities. The average total breast implant volume was 279.3 cc, received an average mean dose of 12.1 Gy, and a maximum dose of 234.1 Gy. The average percentage of breast implant volume receiving 50%, 75%, 100%, 150%, and 200% of the prescribed dose was 15.6%, 7.03%, 4.6%, 1.58%, and 0.46%, respectively. Absolute volume of breast implants receiving more than 50% of prescribed dose correlated with worse cosmetic outcomes. Conclusions Accelerated partial breast irradiation using a multi-lumen applicator in patients with existing breast implants can safely be performed with promising early clinical results. The presence of the implant did not compromise the ability to achieve dosimetric criteria; however, dose to the implant and the irradiated implant volume may be related with worse cosmetic outcomes. PMID:26816499

  9. Dosimetric characteristics of a new unshielded silicon diode and its application in clinical photon and electron beams

    International Nuclear Information System (INIS)

    Griessbach, Irmgard; Lapp, Markus; Bohsung, Joerg; Gademann, Guenther; Harder, Dietrich

    2005-01-01

    Shielded p-silicon diodes, frequently applied in general photon-beam dosimetry, show certain imperfections when applied in the small photon fields occurring in stereotactic or intensity modulated radiotherapy (IMRT), in electron beams and in the buildup region of photon beam dose distributions. Using as a study object the shielded p-silicon diode PTW 60008, well known for its reliable performance in general photon dosimetry, we have identified these imperfections as effects of electron scattering at the metallic parts of the shielding. In order to overcome these difficulties a new, unshielded diode PTW 60012 has been designed and manufactured by PTW Freiburg. By comparison with reference detectors, such as thimble and plane-parallel ionization chambers and a diamond detector, we could show the absence of these imperfections. An excellent performance of the new unshielded diode for the special dosimetric tasks in small photon fields, electron beams and build-up regions of photon beams has been observed. The new diode also has an improved angular response. However, due to its over-response to low-energy scattered photons, its recommended range of use does not include output factor measurements in large photon fields, although this effect can be compensated by a thin auxiliary lead shield

  10. Dosimetric and radiobiological comparison of TG-43 and Monte Carlo calculations in 192Ir breast brachytherapy applications.

    Science.gov (United States)

    Peppa, V; Pappas, E P; Karaiskos, P; Major, T; Polgár, C; Papagiannis, P

    2016-10-01

    To investigate the clinical significance of introducing model based dose calculation algorithms (MBDCAs) as an alternative to TG-43 in 192 Ir interstitial breast brachytherapy. A 57 patient cohort was used in a retrospective comparison between TG-43 based dosimetry data exported from a treatment planning system and Monte Carlo (MC) dosimetry performed using MCNP v. 6.1 with plan and anatomy information in DICOM-RT format. Comparison was performed for the target, ipsilateral lung, heart, skin, breast and ribs, using dose distributions, dose-volume histograms (DVH) and plan quality indices clinically used for plan evaluation, as well as radiobiological parameters. TG-43 overestimation of target DVH parameters is statistically significant but small (less than 2% for the target coverage indices and 4% for homogeneity indices, on average). Significant dose differences (>5%) were observed close to the skin and at relatively large distances from the implant leading to a TG-43 dose overestimation for the organs at risk. These differences correspond to low dose regions (<50% of the prescribed dose), being less than 2% of the prescribed dose. Detected dosimetric differences did not induce clinically significant differences in calculated tumor control probabilities (mean absolute difference <0.2%) and normal tissue complication probabilities. While TG-43 shows a statistically significant overestimation of most indices used for plan evaluation, differences are small and therefore not clinically significant. Improved MBDCA dosimetry could be important for re-irradiation, technique inter-comparison and/or the assessment of secondary cancer induction risk, where accurate dosimetry in the whole patient anatomy is of the essence. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  11. SU-F-J-87: Impact Of The Dosimetric Consequences From Minimal Displacements Throughout The Treatment Time In APBI With SAVI Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekara, S; Pella, S [21st Century Oncology, Boca Raton, FL (United States); Hyvarinen, M; Pinder, J [Florida Atlantic University, Boca Raton, FL (United States)

    2016-06-15

    Purpose: To assess the variation in dose received by the organs at risk (OARs) due to inter-fractional motion by SAVI to determine the importance of providing proper immobilization Methods: An analysis of 15 patients treated with SAVI applicators were considered for this study. Treatment planning teams did not see significant changes in their CT scans through scout images and initial treatment plan was used for the entire treatment. These scans, taken before each treatment were imported in to the treatment planning system and were fused together with respective to the applicator, using landmark registration. Dosimetric evaluations were performed. Dose received by skin, ribs and PTV(Planning target volume) respect to the initial treatment plan were measured. Results: Contours of the OARs were not similar with the initial image. Deduction in volumes of PTV and cavity, small deviations in displacements from the applicator to the OARs, difference in doses received by the OARs between treatments were noticed. The maximum, minimum, average doses varied between 10% to 20% 5% to 8% and 15% to 20% in ribs and skin. The 0.1cc doses to OARs showed an average change of 10% of the prescribed dose. PTV was receiving a different dose than the estimated dose Conclusion: The variation in volumes and isodoses related to the OARs, PTV receiving a lesser dose than the prescribed dose indicate that the estimated doses are different from the received dose. This study reveals the urgent need of improving the immobilization methods. Taking a CT scan before each treatment and replanning is helpful to minimize the risk of delivering undesired high doses to the OARs. Patient positioning, motion, respiration, observer differences and time lap between the planning and treating can arise more complications. VacLock, Positioning cushions, Image guided brachytherapy and adjustable registration should be used for further improvements.

  12. Development and application of a dosimetric methodology of therapeutic X radiation beams using a tandem system; Desenvolvimento e aplicacao de metodologia dosimetrica de feixes terapeuticos de raios X com sistema tandem

    Energy Technology Data Exchange (ETDEWEB)

    Sartoris, Carla Eri

    2001-07-01

    In radiotherapy the use of orthovoltage X radiation beams is still recommended; to obtain satisfactory results, a periodic control is necessary to check the performance of the ionization chambers and the radiation beams characteristics. This control is performed by using standard dosimetric procedures, as for example the determination of half-value layers and the absorbed dose rates. A Tandem system was established in this work using a pair of ionization chambers (a thimble type and a superficial type) used for measures in a medical institution, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The results obtained show the application of this method in dosimetric procedures of orthovoltage beams (radiotherapy) as a complement for a quality control program. (author)

  13. SU-F-19A-04: Dosimetric Evaluation of a Novel CT/MR Compatible Fletcher Applicator for Intracavitary Brachytherapy of the Cervix Uteri

    International Nuclear Information System (INIS)

    Gifford, K; Han, T; Mourtada, F; Eifel, P

    2014-01-01

    Purpose: To validate a Monte Carlo model and evaluate the dosimetric capabilities of a novel commercial CT/MR compatible Fletcher applicator for cervical cancer brachytherapy. Methods: MCNPX 2.7.0 was used to model the Fletcher CT/MR shielded applicator (FA) and 192Ir HDR source. Energy deposition was calculated with a track length estimator modified by an energy-dependent heating function. A high density polystyrene phantom was constructed with three film pockets for validation of the MCNPX model. Three planes of data were calculated with the MCNPX model corresponding to the three film planes in phantom. The planes were located 1 cm from the most anterior, posterior, and medial extents of the FA right ovoid. Unshielded distributions were calculated by modeling the shielded cells as air instead of the tungsten alloy. A third order polynomial fit to the OD to dose curve was used to convert OD of the three film planes to dose. Each film and MCNPX plane dose distribution was normalized to a point 2 cm from the center of the film plane and in a region of low dose gradient. MCNPX and film were overlaid and compared with a distance-to-agreement criterion of (±2%/±2mm). Shielded and unshielded distributions were overlaid and a percent shielded plot was created. Results: 85.2%, 97.1%, and 96.6% of the MCNPX points passed the (±2%/±2mm) criterion respectively for the anterior, lateral, and posterior film comparison planes. A majority of the points in the anterior plane that exceeded the DTA criterion were either along edges of where the film was cut or near the terminal edges of the film. The percent shielded matrices indicated that the maximum % shielding was 50%. Conclusion: These data confirm the validity of the FA Monte Carlo model. The FA ovoid can shield up to 50% of the dose in the anteroposterior direction

  14. SU-F-19A-04: Dosimetric Evaluation of a Novel CT/MR Compatible Fletcher Applicator for Intracavitary Brachytherapy of the Cervix Uteri

    Energy Technology Data Exchange (ETDEWEB)

    Gifford, K; Han, T [UT MD Anderson Cancer Center, Houston, TX (United States); Mourtada, F [Christiana Care Hospital, Newark, DE (United States); Eifel, P [The UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To validate a Monte Carlo model and evaluate the dosimetric capabilities of a novel commercial CT/MR compatible Fletcher applicator for cervical cancer brachytherapy. Methods: MCNPX 2.7.0 was used to model the Fletcher CT/MR shielded applicator (FA) and 192Ir HDR source. Energy deposition was calculated with a track length estimator modified by an energy-dependent heating function. A high density polystyrene phantom was constructed with three film pockets for validation of the MCNPX model. Three planes of data were calculated with the MCNPX model corresponding to the three film planes in phantom. The planes were located 1 cm from the most anterior, posterior, and medial extents of the FA right ovoid. Unshielded distributions were calculated by modeling the shielded cells as air instead of the tungsten alloy. A third order polynomial fit to the OD to dose curve was used to convert OD of the three film planes to dose. Each film and MCNPX plane dose distribution was normalized to a point 2 cm from the center of the film plane and in a region of low dose gradient. MCNPX and film were overlaid and compared with a distance-to-agreement criterion of (±2%/±2mm). Shielded and unshielded distributions were overlaid and a percent shielded plot was created. Results: 85.2%, 97.1%, and 96.6% of the MCNPX points passed the (±2%/±2mm) criterion respectively for the anterior, lateral, and posterior film comparison planes. A majority of the points in the anterior plane that exceeded the DTA criterion were either along edges of where the film was cut or near the terminal edges of the film. The percent shielded matrices indicated that the maximum % shielding was 50%. Conclusion: These data confirm the validity of the FA Monte Carlo model. The FA ovoid can shield up to 50% of the dose in the anteroposterior direction.

  15. Establishment of a dosimetric system for high doses using glasses

    International Nuclear Information System (INIS)

    Correa Quezada, Valeria de la Asuncion

    1997-01-01

    A routine dosimetric system was developed using commercial glass samples. The dosimetric characteristics of national and imported samples were studied: batch uniformity, response repeatability, reutilization, absorbed dose response, detection range, response stability as a function of absorbed dose, storage temperature and thermal treatments pre- and post-irradiation, using the optical absorption technique. As an application, the dosimetric system was tested in a flower irradiation process at IPEN. All the obtained results show the usefulness of the proposed system for high dose dosimetry. (author)

  16. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina

    International Nuclear Information System (INIS)

    Guimaraes, Roger Guilherme Rodrigues

    2009-01-01

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  17. MO-G-17A-04: Internal Dosimetric Calculations for Pediatric Nuclear Imaging Applications, Using Monte Carlo Simulations and High-Resolution Pediatric Computational Models

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, P; Kagadis, GC [University of Patras, Rion, Ahaia (Greece); Loudos, G [Technical Educational Institute of Athens, Aigaleo, Attiki (Greece)

    2014-06-15

    Purpose: Our purpose is to evaluate the administered absorbed dose in pediatric, nuclear imaging studies. Monte Carlo simulations with the incorporation of pediatric computational models can serve as reference for the accurate determination of absorbed dose. The procedure of the calculated dosimetric factors is described, while a dataset of reference doses is created. Methods: Realistic simulations were executed using the GATE toolkit and a series of pediatric computational models, developed by the “IT'IS Foundation”. The series of the phantoms used in our work includes 6 models in the range of 5–14 years old (3 boys and 3 girls). Pre-processing techniques were applied to the images, to incorporate the phantoms in GATE simulations. The resolution of the phantoms was set to 2 mm3. The most important organ densities were simulated according to the GATE “Materials Database”. Several used radiopharmaceuticals in SPECT and PET applications are being tested, following the EANM pediatric dosage protocol. The biodistributions of the several isotopes used as activity maps in the simulations, were derived by the literature. Results: Initial results of absorbed dose per organ (mGy) are presented in a 5 years old girl from the whole body exposure to 99mTc - SestaMIBI, 30 minutes after administration. Heart, kidney, liver, ovary, pancreas and brain are the most critical organs, in which the S-factors are calculated. The statistical uncertainty in the simulation procedure was kept lower than 5%. The Sfactors for each target organ are calculated in Gy/(MBq*sec) with highest dose being absorbed in kidneys and pancreas (9.29*10{sup 10} and 0.15*10{sup 10} respectively). Conclusion: An approach for the accurate dosimetry on pediatric models is presented, creating a reference dosage dataset for several radionuclides in children computational models with the advantages of MC techniques. Our study is ongoing, extending our investigation to other reference models and

  18. MO-G-17A-04: Internal Dosimetric Calculations for Pediatric Nuclear Imaging Applications, Using Monte Carlo Simulations and High-Resolution Pediatric Computational Models

    International Nuclear Information System (INIS)

    Papadimitroulas, P; Kagadis, GC; Loudos, G

    2014-01-01

    Purpose: Our purpose is to evaluate the administered absorbed dose in pediatric, nuclear imaging studies. Monte Carlo simulations with the incorporation of pediatric computational models can serve as reference for the accurate determination of absorbed dose. The procedure of the calculated dosimetric factors is described, while a dataset of reference doses is created. Methods: Realistic simulations were executed using the GATE toolkit and a series of pediatric computational models, developed by the “IT'IS Foundation”. The series of the phantoms used in our work includes 6 models in the range of 5–14 years old (3 boys and 3 girls). Pre-processing techniques were applied to the images, to incorporate the phantoms in GATE simulations. The resolution of the phantoms was set to 2 mm3. The most important organ densities were simulated according to the GATE “Materials Database”. Several used radiopharmaceuticals in SPECT and PET applications are being tested, following the EANM pediatric dosage protocol. The biodistributions of the several isotopes used as activity maps in the simulations, were derived by the literature. Results: Initial results of absorbed dose per organ (mGy) are presented in a 5 years old girl from the whole body exposure to 99mTc - SestaMIBI, 30 minutes after administration. Heart, kidney, liver, ovary, pancreas and brain are the most critical organs, in which the S-factors are calculated. The statistical uncertainty in the simulation procedure was kept lower than 5%. The Sfactors for each target organ are calculated in Gy/(MBq*sec) with highest dose being absorbed in kidneys and pancreas (9.29*10 10 and 0.15*10 10 respectively). Conclusion: An approach for the accurate dosimetry on pediatric models is presented, creating a reference dosage dataset for several radionuclides in children computational models with the advantages of MC techniques. Our study is ongoing, extending our investigation to other reference models and evaluating the

  19. Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

    International Nuclear Information System (INIS)

    Sandilos, Panagiotis; Baras, Panagiotis; Georgiou, Evangelos; Dardoufas, Konstantinos; Karaiskos, Pantelis; Papagiannis, Panagiotis; Paschalis, Theodoros; Tatsis, Elias; Torrens, Michael; Vlahos, Lampros

    2006-01-01

    Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an 192 Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications

  20. Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

    Energy Technology Data Exchange (ETDEWEB)

    Sandilos, Panagiotis [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Baras, Panagiotis [Philips Hellas Medical Systems, 44 Kifissias Ave., Maroussi 151 25, Athens (Greece); Georgiou, Evangelos [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Dardoufas, Konstantinos [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Karaiskos, Pantelis [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece)]. E-mail: p.karaiskos@hygeia.gr; Papagiannis, Panagiotis [Physics Department, Nuclear and Particle Physics Section, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Paschalis, Theodoros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Tatsis, Elias [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Torrens, Michael [Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Vlahos, Lampros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece)

    2006-12-20

    Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an {sup 192}Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications.

  1. The application of data derived from autoradiographic studies with 241Pu in the formulation of a bone dosimetric model for 239Pu

    International Nuclear Information System (INIS)

    Priest, N.D.; Hunt, B.W.

    1979-01-01

    Recently a dosimetric model for 239 Pu in bone has been published which in conjunction with the general ICRP dosimetric model for actinides is used to calculate annual limits of intake for 239 Pu. This model allows for the burial of plutonium in bone, for the recycling of plutonium within the skeleton and for the retention of plutonium in the bone marrow. The model was based upon published descriptions of the distribution and redistribution patterns of plutonium in bone and on evidence obtained from autoradiographic studies of bone from animals injected with 241 Pu. The experiments with 241 Pu demonstrated the initial uptake of plutonium by bone surfaces. As a result of the growth and drift processes much of this plutonium became either buried in the bone or was retained within macrophages in the bone marrow. (author)

  2. Dosimetric investigations in mammography

    International Nuclear Information System (INIS)

    Metges, P.J.; Lorrain, S.

    1981-01-01

    The development film-screen detectors in radiological equipment has led us to study how to improve standard mammographic pictures (focus 0.3 x 0.3 mm, focus-film distance: 65) of thick and dense breasts by the use of an anti-scatter grid and by magnification. A dosimetric study was necessary to assess the doses delivered during mammographic examinations carried out according to various procedures. The results led to modify breast examination procedures and use an anti-scatter grid for breasts thicker than 4 cm or known as dense. The dose increase due to a better quality image is the lowest provided depth penetration is increased by 2 kV as compared to a standard picture. Absorbed doses on the X-ray axis, at 3 cm depth, are below 0.1 rad [fr

  3. Production of LiF films for dosimetric thermoluminescence application; Producao de filmes de LiF para aplicacao em dosimetria termoluminescente

    Energy Technology Data Exchange (ETDEWEB)

    Mauricio, Claudia Lucia de Pinho

    2000-12-01

    This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F{sub 2} NaF and Cu F{sub 2} to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a {sup 60} Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F{sub 2}: LiF; Mg F{sub 2} films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F{sub 2} : LiF: Mg F{sub 2} films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F{sub 2} layer to the Li

  4. Simulation of the flow phenomena in geothermal wells: developments and applications; Simulacion de los fenomenos de flujo en pozos geotermicos: desarrollos y aplicaciones

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1994-07-01

    In this paper the numerical simulators and the specialized computer programs that have been developed in the Departamento de Geotermia of the Instituto de Investigaciones Electricas (IIE) for the study of mass transport phenomena, momentum and heat in geothermal wells, are delineated. The developments can be assembled in 5 types: a) Fluid circulation during geothermal well construction; b) Production; c) Construction; d) Return to the thermal equilibrium; e) Thermodynamic and fluid transport properties, cements, and rocks. The applications realized include, besides the normal flow phenomena that occur in geothermal wells, the study of special problems that have been found in several wells of the geothermal fields in the country. These developments constitute a tool of great utility for the reservoir engineer`s daily work and for the understanding of the specific phenomena of infrequent occurrence. [Espanol] En este trabajo se describen los simuladores numericos y programas de computo especializados que se han desarrollado en el Departamento de Geotermia del Instituto de Investigaciones Electricas (IIE), para estudiar los fenomenos de transporte de masa, momentum y calor en pozos geotermicos. Los desarrollos pueden agruparse en 5 tipos: a) circulacion de fluidos durante la construccion de pozos, b) produccion, c) inyeccion, d) retorno a equilibrio termico, e) propiedades termodinamicas y de transporte de los fluidos, cementos y rocas. Las aplicaciones realizadas incluyen, ademas de los fenomenos normales de flujo que ocurren en pozos geotermicos, el estudio de problemas especiales que se han encontrado en diversos pozos de los campos geotermicos del pais. Estos desarrollos constituyen una herramienta de gran utilidad para el trabajo diario del ingeniero de yacimientos y para el entendimiento de fenomenos especificos de ocurrencia poco frecuente.

  5. Dosimetric system for prolonged manned flights

    International Nuclear Information System (INIS)

    Akatov, Yu.A.; Kovalev, E.E.; Sakovich, V.A.; Deme, Sh.; Fekher, I.; Nguen, V.D.

    1991-01-01

    Comments for the All-Union state standard 25645.202-83 named Radiation safety of a spacecraft crew during space flight. Requirements for personnel dosimetric control, are given. Devices for the dosimetric control used in manned space flights nowadays are reviewed. The performance principle and structure of the FEDOR dosimetric complex under development are discussed

  6. Dosimetric essay in dental radiology

    International Nuclear Information System (INIS)

    Lopez Salaberry, M.

    1998-01-01

    A neck study was observated in the tiroids glands,laryngeal zone, sensitive organs for the ionizing radiation for increase dental xray exams. Was selected 29th patients with radiography prescription complete (in the Odontology Faculty Clinics Uruguaian). It took radiographies with and without tiroids necklace and apron lead using dosemeters. Dosimetric studies had demonstrated good dose between patients. For measuring the radiation dose have been used TLD thermoluminescence dosimetric and Harshaw 6600 for read it. The thyroids necklace use and odontology postgrading for training course for dentistry was the two recommendations advised

  7. The dosimetric control in radiotherapy

    International Nuclear Information System (INIS)

    Veres, A.

    2009-01-01

    The author first presents the thermoluminescent dosimetry method developed by the Equal-Estro Laboratory to control radiotherapy systems, according to which dosimeters are mailed by the radiotherapy centres to the laboratory, and then analyzed with respect to the level of dose bias. In a second part, he discusses the different techniques used for the dosimetric control of new radiotherapy methods (intensity-modulated radiation therapy, tomo-therapy) for which film dosimetry is applied. He also evokes the development of new phantoms and the development of a method for the dosimetric control of proton beams

  8. Discussion on concepts for radiological dosimetric quantities in the Japan Health Physics Society

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Oda, Keiji

    2007-01-01

    Many dosimetric quantities have been used for radiation protection purpose. The International Commission on Radiological Protection (ICRP) has recommended protection quantities and the International Commission on Radiation Units and Measurements (ICRU) has introduced operational quantities to provide a reasonable estimate of the protection quantities. Enthusiastic discussions are continuously made on the issues of the dosimetric quantities, such as basic biological data for the definition of these quantities and applicability of the quantities to actual radiation protection practice. At the moment, some changes are being proposed concerning dosimetric quantities in the draft recommendations of ICRP, opened for consultation in recent years. Thus, the Japan Health Physics Society (JHPS) established the Expert Committee on concepts of Dosimetric Quantities used in radiological protection (ECDQ) in April 2005 to reviewed and discuss issues in the dosimetric quantities. (author)

  9. Study of a new dosimetric radio-thermoluminescent systems

    International Nuclear Information System (INIS)

    Cazac, T.C.

    1980-01-01

    This is the first Romanian study to investigate conditions to obtain the radio-thermo-luminescent systems: MgB 4 O 7 :A(A-Nd,Sm,Eu,Dy,Tb,Dy+Sm and Tb+Sm) MgF 2 A (A=Mn,Dy,Tb,Sm,Li), their essential dosimetric characters, as well as the (MgF 2 =Mn) thermophosphorus mixture with a ( 6 LiF) lithium target. An investigation was developed upon a new category of radio-thermoluminescent detectors with low radiation energy dependence and fading, magnesjum boride activated by several elements of the lanthanides class (Nd,Sm,Eu,Dy,Tb). A new radio-thermoluminescent dosimetric system with high sensitivity and moderate dependence on energy radiation - (Mnsup(2+)) manganese activated magnesium fluoride - was also studied. The author explored application of investigated detectors MgF 2 =Mn, MgB 4 O 7 =Dy and MgB 4 O 7 :Tb in neutron dosimetry in complex gamma-neutron fields. It is deemed that by using the dosimetric systems reported in the thesis in order to measure gamma, beta and neutron radiation doses, dosimetric control can be ensured both in professional dosimetry and in nuclear accident dosimetry, as well as in various basic and applicative investigations. A modest contribution is thus made towards achieving the national nuclear program through an extension of the thermophosphorus range with practical applications in nuclear radiation dosimetry. (author)

  10. Mercadeo social y desarrollo

    OpenAIRE

    Luis E. Eladio Proaño

    2015-01-01

    Afirma el autor que todos los proyectos de desarrollo fracasan porque no tienen en cuenta la cooperación de las organizaciones comunitarias. Lograr el apoyo de la población a través de su activa participación en los planes de desarrollo,la ejecución y control de los diferentes programas es uno de los propósitos del "nuevo mercadeo social".

  11. BeOSL system for personal dosimetry : dosimetric characteristics and practical application; Sistema BeOSL para dosimetria personal : caracteristicas dosimetricas y la aplicacion practica

    Energy Technology Data Exchange (ETDEWEB)

    Mende, E. [Helmholtz Zentrum Munchen, German Research Center for Environmental Health, Working Group Engineering, D-85764 Neuherberg (Germany)

    2015-10-15

    Full text: BeOSL system of Dosimetric s is very easy to use, assimilate and maintain. Our dosimeter defines a milestone in the supervision of personal equivalent dose of Hp (10) and Hp (0.07) it covers the range of total energy of 16 KeV to 10 MeV. For this energy range is exceptional in its energy dependence for official personal dosimetry. The BeOSL system consists of two modules, one of them is the BeOSL reader that measures the radiation exposure using the latest technology, optically stimulated luminescence (OSL). The reading is extremely fast; it does not require consumables such as nitrogen or other. The detector material is beryllium oxide (Be O); this is an OSL material tissue equivalent and therefore is ideal for personal dosimetry. The BeOSL technology allows multiple readings of the dosimeter (re-read) to verify the dose or archive the dosimeter. One of the biggest advantages of BeOSL system is its modular concept allows the system to run as a manual solution or as a complete automated robotic system, which can be filled with up to 5,000 dosimeters as bulk cargo. (Author)

  12. Development of a dosimetric system for {sup 90}Sr + {sup 90}Y betatherapy applicators; Desenvolvimento de um sistema de dosimetria para aplicadores de betaterapia de {sup 90}Sr + {sup 90}Y

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Talita Salles

    2010-07-01

    The {sup 90}Sr+{sup 90}Y applicators, used in betatherapy for prevention of keloids and pterigium, are imported and many times their dosimetric features are shown only in an illustrated form by the manufacturers. The exhaustive routine of the medical physicists in the clinic do not make possible the accomplishment of procedures for the confirmation of these parameters. This work presents the development of a methodology for the dosimetry of {sup 90}Sr+{sup 90}Y betatherapy applicators. The Monte Carlo code MCNP5 was used for the simulation of the percentage depth dose curves and dose distribution profiles produced by these applicators. The experimental measurements of the radial and axial radiation attenuation, have been done with a mini-extrapolation chamber, thermoluminescent dosimeters and radiographic films. The experimental results have been compared with the simulated values. Both percentage depth dose curves and the radial dose profiles, the theoretical and the experimental ones, have presented good agreement, which may validate the use of the MCNP5 for these simulations, confirming the viability of the usage of this method in procedures of beta emitter sources dosimetry. (author)

  13. Perspectives of development of ceramic materials with luminescent applications; Perspectivas del desarrollo de materiales ceramicos con aplicaciones luminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado E, A; Fernandez M, J L; Diaz G, J L.I.; Rivera M, T [IPN, Av. Legaria 694, 11500 Mexico D.F. (Mexico)

    2005-07-01

    The science and technology of materials believes and it applies the knowledge that allow to relate the composition, it structures and the one processed with those properties that those they make capable for each one of the applications. The ceramic materials are inorganic materials not metallic, constituted by metallic elements and not metallic. In general, they usually behave, as good insulating electric and thermal due to the absence of conductive electrons. Usually, they possess relatively high coalition temperatures and, also, a chemical stability relatively high. Due to these properties, they are indispensable for many of those designs in engineering. The ceramic materials for luminescent applications are constituted typically by pure compounds (Al{sub 2}O{sub 3}, TiO{sub 2}, SiO{sub 2} and ZrO{sub 2}) or cocktails with some sludges giving as a result (Al{sub 2}O{sub 3}:TR, TiO{sub 2}:Eu, Si:ZrO{sub 2}, ZrO{sub 2}:TR). Presently work describes the panorama to big features on the development of ceramic materials in the CICATA Unit it would Bequeath, which can be characterized by the photoluminescence techniques and thermoluminescence mainly. (Author)

  14. SU-D-19A-05: The Dosimetric Impact of Using Xoft Axxent® Electronic Brachytherapy Source TG-43 Dosimetry Parameters for Treatment with the Xoft 30 Mm Diameter Vaginal Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Simiele, S; Micka, J; Culberson, W; DeWerd, L [University of WI-Madison/ADCL, Madison, WI (United States)

    2014-06-01

    Purpose: A full TG-43 dosimetric characterization has not been performed for the Xoft Axxent ® electronic brachytherapy source (Xoft, a subsidiary of iCAD, San Jose, CA) within the Xoft 30 mm diameter vaginal applicator. Currently, dose calculations are performed using the bare-source TG-43 parameters and do not account for the presence of the applicator. This work focuses on determining the difference between the bare-source and sourcein- applicator TG-43 parameters. Both the radial dose function (RDF) and polar anisotropy function (PAF) were computationally determined for the source-in-applicator and bare-source models to determine the impact of using the bare-source dosimetry data. Methods: MCNP5 was used to model the source and the Xoft 30 mm diameter vaginal applicator. All simulations were performed using 0.84p and 0.03e cross section libraries. All models were developed based on specifications provided by Xoft. The applicator is made of a proprietary polymer material and simulations were performed using the most conservative chemical composition. An F6 collision-kerma tally was used to determine the RDF and PAF values in water at various dwell positions. The RDF values were normalized to 2.0 cm from the source to accommodate the applicator radius. Source-in-applicator results were compared with bare-source results from this work as well as published baresource results. Results: For a 0 mm source pullback distance, the updated bare-source model and source-in-applicator RDF values differ by 2% at 3 cm and 4% at 5 cm. The largest PAF disagreements were observed at the distal end of the source and applicator with up to 17% disagreement at 2 cm and 8% at 8 cm. The bare-source model had RDF values within 2.6% of the published TG-43 data and PAF results within 7.2% at 2 cm. Conclusion: Results indicate that notable differences exist between the bare-source and source-in-applicator TG-43 simulated parameters. Xoft Inc. provided partial funding for this work.

  15. El desarrollo del emprendedor

    OpenAIRE

    Arco Juan, Francisco Javier del

    2010-01-01

    En este trabajo pretendemos abordar el desarrollo de las competencias y de las cualidades del emprendedor. Para ello analizaremos como mediante el trabajo en equipo, el liderazgo y la toma de decisiones a la hora de elaborar un Plan de Negocio, el alumno desarrollo todas estas competencias básicas. Además, por supuesto, de la capacidad de emprender un negocio a través de las herramientas básicas para la puesta en marcha de un negocio. No data (2010) UEM

  16. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

    Teixeira, M.I.; Caldas, L.V.E.

    2006-01-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  17. ARDENT to develop advanced dosimetric techniques

    CERN Document Server

    Antonella Del Rosso

    2012-01-01

    Earlier this week, the EU-supported Marie Curie training network ARDENT kicked off at a meeting held at CERN. The overall aim of the project is the development of advanced instrumentation for radiation dosimetry. The applications range from radiation measurements around particle accelerators, onboard commercial flights and in space, to the characterization of radioactive waste and medicine, where accurate dosimetry is of vital importance.   The ARDENT (Advanced Radiation Dosimetry European Network Training) project is both a research and a training programme, which aims at developing new dosimetric techniques while providing 15 Early-Stage Researchers (ESR) with state-of-the-art training. The project, coordinated by CERN, is funded by the European Union with a contribution of about 3.9 million euros over four years. The ARDENT initiative will focus on three main technologies: gas detectors, in particular Gas Electron Multipliers (GEM) and Tissue Equivalent Proportional Counters (TEPC); solid stat...

  18. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  19. SU-E-T-310: Dosimetric Comparison of Tandem and Ovoid (TO) Vs. Tandem and Ring (TR) Applicators in High-Dose Rate (HDR) Brachytherapy (BT) for the Treatment of Locally-Advanced Cervical-Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, L; Viswanathan, A; Damato, A [Brigham and Women’s Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: To investigate the dosimetric differences associated with the use of TO or TR applicators for cervical-cancer HDR BT. Methods: The records of all cervical-cancer patients treated with image-guided HDR BT in 2013 were reviewed. Image-based planning based on isodose line and DVH metrics inspections was performed following the GEC-ESTRO recommendations. CTV volume, CTV D90, and rectum, bladder and sigmoid D2cc were collected as % of the prescription dose (80Gy EQD2). Patients receiving both TO and TR were identified and plans were compared (paired analysis). A Student T-test was used to evaluate statistical significance (p ≤ 0.05). Results: Twenty-eight patients were identified (20 TR only, 4 TO only, 4 TO and TR), associated with 116 plans (109 TR, 7 TO). Overall metrics: CTV volume, 26.5±10.4 cm3 (TR) and 39.1±14.0 cm3 (TO, p < 0.01); CTV D90, 126±28% (TR) and 110±15% (TO, p = 0.15); rectum D2cc, 56±11% (TR) and 58±19% (TO, p = 0.91); bladder D2cc, 74±20% (TR) and 88±19% (TO, p = 0.09); sigmoid D2cc, 52±17% (TR) and 49±20% (TO, p = 0.63). The paired analysis results were: CTV volume, 37.3±11.9 cm3 (TR) and 51.0±23.1 cm3 (TO, p = 0.23); CTV D90, 111±12% (TR) and 101±17% (TO, p = 0.50); rectum D2cc, 56±12% (TR) and 53±16% (TO, p = 0.71); bladder D2cc, 73±14% (TR) and 90±20% (TO, p = 0.22); sigmoid D2cc, 59±10% (TR) and 59±22% (TO, p = 0.98). Conclusion: TR and TO were both used with good dosimetric results. TO were used for patients with larger CTV volumes than TR, although paired analysis suggest that tissue distortion and contouring bias may partially explain this Result. CTV D90 on average > 80 Gy EQD2 were achieved in both groups despite the different CTV volume. Higher bladder D2cc for TO than TR was observed.

  20. Validation and dosimetric evaluation employing the techniques of TL and OSL of thermoluminescent materials for application in the dosimetry of clinical beams of electrons used in total irradiation of the skin - TSI

    International Nuclear Information System (INIS)

    Almeida, Shirlane Barbosa de

    2017-01-01

    In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. TSI dosimetry is difficult because of the complexity of the treatment in assessing dose uniformity and measuring the dose absorbed at shallow depths throughout the skin surface extent, resulting in a wide variation in dose distribution. The TLDs have proven to be very useful for the distribution and verification of the dose prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. Several types of dosimeters have been used in the radiotherapy sectors, the most commonly used are Lithium Fluride (TLD-100), where it obtains a long history in this type of application. New dosimetric materials have gained great importance in the dosimetry of clinical electron beams, such as Dysprosium-doped Calcium Sulphate (TL) and Carbon doped (OSL) based Aluminum Oxide, This work evaluates the performance of the respective thermoluminescent dosimeters and the optically stimulated luminescence in the dosimetry of clinical electron beams used in total irradiation of the skin. (author)

  1. Competencia Desarrollo del Pensamiento Creativo

    OpenAIRE

    Rodríguez, Eric; Miceli, Francisco; Tiburcio, Georgina; Gómez, Orlando

    2012-01-01

    1. ¿Qué significa la competencia Desarrollo del Pensamiento Creativo? 2. ¿Por qué es relevante que adquiera la competencia Desarrollo del Pensamiento Creativo en mi formación? 3. ¿Cómo aprendo la competencia Desarrollo del Pensamiento Creativo? 4. ¿Cómo aplico la competencia Desarrollo del Pensamiento Creativo? 5. ¿Cómo puedo autoevaluar mi competencia (con miras a un constante crecimiento)?

  2. Dosimetric lung models

    International Nuclear Information System (INIS)

    James, A.C.; Roy, M.

    1986-01-01

    The anatomical and physiological factors that vary with age and influence the deposition of airborne radionuclides in the lung are reviewed. The efficiency with which aerosols deposit in the lung for a given exposure at various ages from birth to adulthood is evaluated. Deposition within the lung is considered in relation to the clearance mechanisms acting in different regions or compartments. The procedure for evaluating dose to sensitive tissues in lung and transfer to other organs that is being considered by the Task Group established by ICRP to review the Lung Model is outlined. Examples of the application of this modelling procedure to evaluate lung dose as a function of age are given, for exposure to radon daughters in dwellings, and for exposure to an insoluble 239 Pu aerosol. The former represents exposure to short-lived radionuclides that deliver relatively high doses to bronchial tissue. In this case, dose rates are marginally higher in children than in adults. Plutonium exposure represents the case where dose is predominantly delivered to respiratory tissue and lymph nodes. In this case, the life-time doses tend to be lower for exposure in childhood. Some of the uncertainties in this modelling procedure are noted

  3. Dosimetric methodology of the ICRP

    International Nuclear Information System (INIS)

    Eckerman, K.F.

    1994-01-01

    Establishment of guidance for the protection of workers and members of the public from radiation exposures necessitates estimation of the radiation dose to tissues of the body at risk. The dosimetric methodology formulated by the International Commission on Radiological Protection (ICRP) is intended to be responsive to this need. While developed for radiation protection, elements of the methodology are often applied in addressing other radiation issues; e.g., risk assessment. This chapter provides an overview of the methodology, discusses its recent extension to age-dependent considerations, and illustrates specific aspects of the methodology through a number of numerical examples

  4. Development of applications in Internet for the calculation of solar control devices; Desarrollo de una aplicacion en Internet para el calculo de dispositivos de control solar

    Energy Technology Data Exchange (ETDEWEB)

    Perez V, Jesus B; Robles G, Saul; Villa M, Hector A; Cabanillas L, Rafael E [Universidad de Sonora, Hermosillo, Sonora (Mexico)

    2000-07-01

    In this work the development of an interactive software, visible over the World Wide Web, is presented to support the basic calculation required to control the solar gain inside buildings and houses. The site has two main parts: one part describes in a very required parameters to design devices for the control of the illumination inside the buildings, like overhangs and wingwalls for shading. The other part has the routines and procedures to calculate the sun position for any date and position over the earth, and the horizontal and vertical protection angles. The part to implement the calculations has been developed as a Java applet which can run on any platform and let the users, in an interactive way, to get the results. This software makes possible that any Internet user can run the application from his/her own computer without having to compile of use sophisticated procedures as it happens with traditional languages. With this web site it is intended to cover the necessity of having simple and reliable means for architects and civil engineers to support the use of solar energy and the saving of energy in bioclimatic design of buildings. [Spanish] En este trabajo se presenta el desarrollo de un sitio interactivo visible en el World Wide Web (WWW) que pretende servir de apoyo para los calculos basicos de control de asoleamiento en viviendas y edificios. El sitio esta conformado por dos partes principales: una parte cubre el aspecto informativo, donde en forma sencilla y clara, se explican los conceptos y parametros necesarios para disenar los dispositivos de control, alerones y parteluces. La otra parte contiene los procedimientos y las rutinas de calculo para la determinacion de la posicion solar para cualquier fecha del ano desde cualquier punto sobre la tierra, asi como los angulos de sombreado vertical y horizontal. Para la realizacion de los calculos se ha construido un applet de Java, el cual puede ejecutarse desde cualquier plataforma de computacion y

  5. El desarrollo sostenible

    Directory of Open Access Journals (Sweden)

    Cuéllar Gálvez David

    1995-12-01

    Full Text Available Las características del desarrollo económico a nivel mundial, los patrones de consumo, los sistemas de producción y de comercialización, especialmente después de la II Guerra Mundial, han tenido como consecuencias el despilfarro de los recursos naturales y la degradación del ambiente. Durante los últimos años y como respuesta a esa situación, se ha venido elaborando el concepto de Desarrollo Sostenible que, en su definición más aceptada, establece que es aquel que atiende las necesidades de las generaciones presentes, sin poner en peligro la capacidad para atender las necesidades de las generaciones futuras.

  6. Radiometric and dosimetric characteristics of HgI2 detectors

    International Nuclear Information System (INIS)

    Zaletin, V.M.; Krivozubov, O.V.; Torlin, M.A.; Fomin, V.I.

    1988-01-01

    The characteristics of HgI 2 detectors in x-ray and gamma detection in applications to radiometric and dosimetric monitoring and as portable instruments for such purposes was considered. Blocks with mosaic and sandwich structures were prepared and tested against each other and, for comparative purposes, against CdTe detectors for relative sensitivities at various gamma-quanta energies. Sensitivity dependencies on gamma radiation energy were plotted for the detector materials and structures as were current dependencies on the dose rate of x rays. Results indicated that the mercury iodide detectors could be used in radiometric and dosimetric measurements at gamma quantum energies up to and in excess of 1000 KeV

  7. SU-G-TeP2-07: Dosimetric Characterization of a New HDR Multi-Channel Esophageal Applicator for Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, A; Gao, S; Greskovich, J; Wilkinson, D [Cleveland Clinic, Cleveland, OH (United States); Diener, T [Cleveland State University, Cleveland, OH (United States)

    2016-06-15

    Purpose: To characterize the dose distribution of a new multi-channel esophageal applicator for brachytherapy HDR treatment, and particularly the effect of the presence of air or water in the applicator’s expansion balloon. Methods: A new multi-channel (6) inflatable applicator for esophageal HDR has been developed in house and tested in a simple water phantom. CT image sets were obtained under several balloon expansions (80ml of air, 50 cc of water), and channel loadings and used with the Oncentra (Elekta) planning system based on TG43 formalism. 400 cGy was prescribed to a plane 1cm away from the applicator. Planar dose distributions were measured for that plane and one next to the applicator using Gafchromic EBT3 film and scanned by a Vidar VXR-12 film digitizer. Film and TPS generated dose distributions of film were sent to OmniPro I’mRT (iba DOSIMETRY) for analysis. 2D dose profiles in both X and Y directions were compared and gamma analysis performed. Results: Film dose measurement of the air-inflated applicator is lower than the TPS calculated dose by as much as 60%. Only 80.8% of the pixels passed the gamma criteria (3%/3mm). For the water-inflated applicator, the measured film dose is fairly close to the TPS calculated dose (typically within <3%). 99.84% of the pixels passed the gamma criteria (3%/3mm). Conclusion: TG43 based calculations worked well when water was used in the expansion balloon. However, when air is present in that balloon, the neglect of heterogeneity corrections in the TG43 calculation results in large differences between calculated and measured doses. This could result in severe underdosing when used in a patient. This study illustrates the need for a TPS with an advanced algorithm which can account for heterogeneity. Supported by Innovations Department, Cleveland Clinic.

  8. Dosimetric comparison of different dose prescription systems with CT based intracavitary brachytherapy and manual back projection technique to reconstruct the applicator

    International Nuclear Information System (INIS)

    Oinam, A.S.; Dubey, S.; Kehwar, T.S.; Rout, Sanjaya K.; Patel, F.D.; Sharma, S.C.; Goyal, D.R.; Narayan, P.

    2002-01-01

    Intracavitary brachytherapy is one of the well-established techniques for the treatment of carcinoma of cervix. The prediction of late effect of normal tissue like rectum and bladder needs the defining of the volume of the bladder and rectum in situ. In the normal planning of intracavitary and interstitial implants, simulated radiograph films are used to reconstruct the applicator geometry and dose points to represent the dose to critical organs. CT based brachytherapy can define such volume instead of defining dose points, which represent the dose to these critical organs

  9. Equidad, desarrollo y paz

    Directory of Open Access Journals (Sweden)

    Jorge Iván GONZÁLEZ

    2009-11-01

    Full Text Available RESUMEN: El eje del artículo es la relación que establece el autor entre desarrollo económico y violencia. En Colombia la situación económica se ha deteriorado en gran medida como consecuencia de la política económica y del modelo de desarrollo y éstos son responsables de la agudización de la violencia. La desigual distribución de la riqueza y la ortodoxia monetaria han estimulado la concentración y han propiciado la exclusión. Aunque la relación no es mecánica, esta situación es un elemento para la rebelión. El costo social de la política económica neoliberal ha sido elevado, a pesar de que los programas sociales han puesto énfasis en la lucha contra la pobreza. Este enfoque debe modificarse, puesto que privilegiando la equidad y aminorando la concentración del ingreso, se estimula el desarrollo, se reduce la pobreza y en consecuencia, se crea un clima propicio para el diálogo y la paz.ABSTRACT: The core of the article is the relationship between economic development and violence that the author establishes. The economic situation in Colombia has been deterioring as consequence of the economic policy and the way of development. Both of them are responsibles of the violence intensification. The unequal wealth distribution and monetary orthodoxy have stimulated the concentration and have created a favorable atmosphere for exclusion. The social cost of neoliberal economic policies has been high despite the fact that social programs have focused on fighting poverty. This approach must be modified. Development is stimulated by granting privilege to equality and reducing the income concentration . In doing so, the rigth atmosphere for dialogue and peace is created.

  10. Application of a Monte Carlo Penelope code at diverse dosimetric problems in radiotherapy; Aplicacion del codigo Monte Carlo Penelope a diversos problemas dosimetricos en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.A.; Fernandez V, J.M.; Salvat, F. [Servicio de Oncologia Radioterapica. Hospital Clinico de Barcelona. Villarroel 170 08036 Barcelona (Spain)

    1998-12-31

    In the present communication it is presented the results of the simulation utilizing the Penelope code (Penetration and Energy loss of Positrons and Electrons) in several applications of radiotherapy which can be the radioactive sources simulation: {sup 192} Ir, {sup 125} I, {sup 106} Ru or the electron beams simulation of a linear accelerator Siemens KDS. The simulations presented in this communication have been on computers of type Pentium PC of 100 throughout 300 MHz, and the times of execution were from some hours until several days depending of the complexity of the problem. It is concluded that Penelope is a very useful tool for the Monte Carlo calculations due to its great ability and its relative handling facilities. (Author)

  11. Radiochromic film in the dosimetric verification of intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Zhou Yingjuan; Huang Shaomin; Deng Xiaowu

    2007-01-01

    Objective: Objective To investigate the dose-response behavior of a new type of radio- chromic film( GAFCHROMIC EBT) and explore the clinical application means and precision of dosage measurement, which can be applied for: (1) plan-specific dosimetric verification for intensity modulated radiation therapy, (2) to simplify the process of quality assurance using traditional radiographic film dosimetric system and (3) to establish a more reliable, more efficient dosimetric verification system for intensity modulated radiation therapy. Methods: (1) The step wedge calibration technique was used to calibrate EBT radiochromic film and EDR2 radiographic film. The dose characteristics, the measurement consistency and the quality assurance process between the two methods were compared. (2) The in-phantom dose-measurement based verification technique has been adopted. Respectively, EBT film and EDR2 film were used to measure the same dose plane of IMRT treatment plans. The results of the dose map, dose profiles and iso- dose curves were compared with those calculated by CORVUS treatment planning system to evaluate the function of EBT film for dosimetric verification for intensity modulated radiation therapy. Results: (1) Over the external beam dosimetric range of 0-500 cGy, EBT/VXR-16 and EDR2/VXR-16 film dosimetric system had the same measurement consistency with the measurement variability less then 0.70%. The mean measurement variability of these two systems was 0.37% and 0.68%, respectively. The former proved to be the superior modality at measurement consistency, reliability, and efficiency over dynamic clinical dose range , furthermore, its quality assurance showed less process than the latter. (2) The dosimetric verification of IMRT plane measured with EBT film was quite similar to that with EDR2 film which was processed under strict quality control. In a plane of the phantom, the maximal dose deviation off axis between EBT film measurement and the TPS calculation was

  12. Dosimetric system for measurement of radioactive contaminations

    International Nuclear Information System (INIS)

    Litynski, Z.; Pienkos, J.P.; Witkowski, J.; Zadrozny, S.

    1985-01-01

    A dosimetric system for personnel dosimetry and monitoring measuring a contamination without time delay and dead time is described. The system ensures many-point measurement and minimalization of background radiation influence. 1 fig. (A.S.)

  13. Synthesis and luminescence behavior of SrGd1.76Eu0.24O4 host for display and dosimetric applications

    Science.gov (United States)

    Singh, Jyoti; Manam, J.; Singh, Fouran

    2018-05-01

    Novel SrGd1.76Eu0.24O4 materials were synthesized by conventional high-temperature solid-state reaction method in air ambiance. The structural and luminescence properties of as-prepared phosphors were explored by XRD, FESEM, TEM, PL and TL techniques. The confirmation of orthorhombic phase formation was obtained by XRD studies. The agglomerated ginger-like morphology of as-synthesized SrGd1.76Eu0.24O4 samples was unfolded by FESEM and TEM studies. Upon 276 and 395 nm UV excitation, SrGd1.76Eu0.24O4 phosphors showed intense red emission. The TL glow curve of SrGd1.76Eu0.24O4 irradiated with γ-rays exhibits two well-resolved peaks at 393 K and 598 K having a shoulder at 537 K. Linearity in a wide dose range 500 Gy-3 kGy are observed in the as-formed SrGd1.76Eu0.24O4 samples. Intense red emission, linear dose response and high reproducibility of SrGd1.76Eu0.24O4 samples broadly indicated its suitability for display and TL dosimetry applications.

  14. SU-E-T-382: Evaluation of Clinical Application and Dosimetric Comparison for Treatment Plans of Gamma Knife and CyberKnife for Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C [Department of Radiation Oncology, Shuang Ho Hospital, Taipei Medical Univer, New Taipei City, Taiwan (R.O.C.) (China)

    2015-06-15

    Purpose: To analyze and compare the characteristics of dose distributions between Gamma Knife (GK) and CyberKnife (CK), in treating arteriovenous malformations (AVMs), and evaluate the influences on their clinical applications. Methods: Twenty four patients with AVMs treated with CK of prescribed dose (PD) of 16–25 Gy in single fraction were selected. Each patient’s CT images used for CK treatment planning with contours of targets and critical organs were exported and then loaded into the GK planning system. GK treatment plan with the same PD used in CK was generated for each patient. The metrics for dose comparison between GK and CK included conformity index (CI), gradient index (GI) of 75%, 50% and 25% of the PD, heterogeneity index (HI), volume of brain tissues covered by 10 Gy and 12 Gy, maximum dose to brainstem and beam-on time. Paired Samples t-test was used to analyze these metrics for significance (p value). Results: The CI were 0.744 ± 0.075 (GK) and 0.768 ± 0.086 (CK), p = 0.281. The GI75%, GI50%, and GI25% in GK and CK were 1.735 ± 0.100 and 2.439 ± 0.338 (p < 0.001), 3.169 ± 0.265 and 4.972 ± 0.852 (p < 0.001), and 8.650 ± 0.914 and 14.261 ± 2.476 (p < 0.001). The HI were 0.728 ± 0.072 (GK) and 0.313 ± 0.069 (CK), p < 0.001. There were significant differences both for volume of brain tissues covered by 10 Gy and 12 Gy in GK and CK (p < 0.001). GK had smaller maximum dose to brainstem. CK had shorter beam-on time. Conclusion: GK has similar dose conformity as CK, and has better normal tissue sparing but is less efficient than CK.

  15. SU-E-T-382: Evaluation of Clinical Application and Dosimetric Comparison for Treatment Plans of Gamma Knife and CyberKnife for Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Kuo, C

    2015-01-01

    Purpose: To analyze and compare the characteristics of dose distributions between Gamma Knife (GK) and CyberKnife (CK), in treating arteriovenous malformations (AVMs), and evaluate the influences on their clinical applications. Methods: Twenty four patients with AVMs treated with CK of prescribed dose (PD) of 16–25 Gy in single fraction were selected. Each patient’s CT images used for CK treatment planning with contours of targets and critical organs were exported and then loaded into the GK planning system. GK treatment plan with the same PD used in CK was generated for each patient. The metrics for dose comparison between GK and CK included conformity index (CI), gradient index (GI) of 75%, 50% and 25% of the PD, heterogeneity index (HI), volume of brain tissues covered by 10 Gy and 12 Gy, maximum dose to brainstem and beam-on time. Paired Samples t-test was used to analyze these metrics for significance (p value). Results: The CI were 0.744 ± 0.075 (GK) and 0.768 ± 0.086 (CK), p = 0.281. The GI75%, GI50%, and GI25% in GK and CK were 1.735 ± 0.100 and 2.439 ± 0.338 (p < 0.001), 3.169 ± 0.265 and 4.972 ± 0.852 (p < 0.001), and 8.650 ± 0.914 and 14.261 ± 2.476 (p < 0.001). The HI were 0.728 ± 0.072 (GK) and 0.313 ± 0.069 (CK), p < 0.001. There were significant differences both for volume of brain tissues covered by 10 Gy and 12 Gy in GK and CK (p < 0.001). GK had smaller maximum dose to brainstem. CK had shorter beam-on time. Conclusion: GK has similar dose conformity as CK, and has better normal tissue sparing but is less efficient than CK

  16. Dosimetric studies in diagnostic radiology

    International Nuclear Information System (INIS)

    Mohamadain, K. E. M.

    2004-04-01

    A dosimetric study in pediatric radiology and adult patients was currently being carried out at the pediatrics units of two large hospitals in Rio de Janeiro city: IPPMG (Instituto de Pediatric e Puericultura Martagao Gesteira, University hospital of federal University of Rio de Janeiro), IFF (Instituto Fernandes Figueira, FIOCRUZ) and Hospital Geral de Bonsucesso, a large public hospital in Rio de Janeiro city (HGB) Brazil. The dosimetric study was also performed at three pediatrics units in Sudan, namely, Ahmed Gasim, Khartoum and Omdurman hospitals. For chest x-ray examination the entrance skin dose(ESD) for AP, PA and LAT projections of pediatric patients, and the scattered dose at the thyroid, ovary and gonads have been obtained with thermoluminescent dosimeters (TLD) and with use of a software package Dosecal in thr Brazilian hospitals, and with the software dosecal in the Sudanese hospitals.The aim of this work was to estimate the entrance skin dose (ESD), the effective dose (ED) and the body organ dose (BOD) for chest x-ray exposure in pediatric patients, and different exams for adults patients, and to compare the results obtained in the tow Countries Sudan and Brazil with the reference dose level. For ESD evaluation of the chest x-ray, three different TL dosimeters have been used, namely LiF: Mg, Ti (TLD 100) CaSo 4 : Dy and LiF:Mg, Cu,P (TLD 100 H). The age intervals considered were: 0-1 years, 1-5 years, 5-10 years and 10-15 years. The results obtained with all dosimeters were in good agreement with, those obtained by the dosecal software, especially for AP and PA projection. However, some discrepancies were found for the LAT projection. The results within Brazil were some what consistent while in Sudan, large difference were observed, it was also noted that the doses in Brazil hospitals were less than the reference dose levels while in Sudanese hospitals the doses were higher than the reference dose levels. For adult patients only the software dosecal

  17. Dosimetric properties of MOS transistors

    International Nuclear Information System (INIS)

    Frank, H.; Petr, I.

    1977-01-01

    The structure of MOS transistors is described and their characteristics given. The experiments performed and data in the literature show the following dosimetric properties of MOS transistors: while for low gamma doses the transistor response to exposure is linear, it shows saturation for higher doses (exceeding 10 3 Gy in tissue). The response is independent of the energy of radiation and of the dose rate (within 10 -2 to 10 5 Gy/s). The spontaneous reduction with time of the spatial charge captured by the oxide layer (fading) is small and acceptable from the point of view of dosimetry. Curves are given of isochronous annealing of the transistors following irradiation with 137 Cs and 18 MeV electrons for different voltages during irradiation. The curves show that in MOS transistors irradiated with high-energy electrons the effect of annealing is less than in transistors irradiated with 137 Cs. In view of the requirement of using higher temperatures (approx. 400 degC) for the complete ''erasing'' of the captured charge, unsealed systems must be used for dosimetric purposes. The effect was also studied of neutron radiation, proton radiation and electron radiation on the MOS transistor structure. For MOS transistor irradiation with 14 MeV neutrons from a neutron generator the response was 4% of that for gamma radiation at the same dose equivalent. The effect of proton radiation was studied as related to the changes in MOS transistor structure during space flights. The response curve shapes are similar to those of gamma radiation curves. The effect of electron radiation on the MOS structure was studied by many authors. The experiments show that for each thickness of the SiO 2 layer an electron energy exists at which the size of the charge captured in SiO 2 is the greatest. All data show that MOS transistors are promising for radiation dosimetry. The main advantage of MOS transistors as gamma dosemeters is the ease and speed of evaluation, low sensitivity to neutron

  18. Transport and dosimetric solutions for the ELIMED laser-driven beam line

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G.A.P. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Romano, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Scuderi, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Amato, A. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Candiano, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Cuttone, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Giove, D. [INFN Sezione di Milano, Via Celoria 16, Milano (Italy); Korn, G.; Krasa, J. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Leanza, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Manna, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Maggiore, M. [INFN-LNL, Viale dell' Universitá 2 - 35020 Legnaro (PD) (Italy); Marchese, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Margarone, D. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Milluzzo, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Petringa, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Sabini, M.G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Azienda Ospedaliera Cannizzaro, Via Messina 829 - 95100 Catania (Italy); Schillaci, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); and others

    2015-10-01

    Within 2017, the ELIMED (ELI-Beamlines MEDical applications) transport beam-line and dosimetric systems for laser-generated beams will be installed at the ELI-Beamlines facility in Prague (CZ), inside the ELIMAIA (ELI Multidisciplinary Applications of laser–Ion Acceleration) interaction room. The beam-line will be composed of two sections: one in vacuum, devoted to the collecting, focusing and energy selection of the primary beam and the second in air, where the ELIMED beam-line dosimetric devices will be located. This paper briefly describes the transport solutions that will be adopted together with the main dosimetric approaches. In particular, the description of an innovative Faraday Cup detector with its preliminary experimental tests will be reported.

  19. Salud Mental y desarrollo

    Directory of Open Access Journals (Sweden)

    María José Sarmiento Suárez

    2017-09-01

    Full Text Available La relación entre salud mental y desarrollo es tan estrecha como ignorada. Aunque ambas buscan potenciar las capacidades de los individuos para lograr un bienestar individual que redunde en la comunidad, la salud mental ha sido sistemáticamente excluida de los planes de desarrollo. Los problemas de salud mental afectan a millones de personas en el mundo quienes, al no recibir un tratamiento adecuado y oportuno, pueden desarrollar un trastorno. Se calcula que una de cada cuatro personas desarrolla algún tipo de enfermedad mental a lo largo de su vida. En tanto se cree que no es posible recuperarse de estas enfermedades, los recursos no están dirigidos a intervenir sobre ellas. Siendo absolutamente transversal a todos los aspectos de nuestras vidas, y por tanto un pilar fundamental en el desarrollo sostenible, el gasto global en salud mental es de menos de dos dólares por persona por día. Situación que no sólo impacta directamente sobre las tres dimensiones del Índice de Desarrollo Humano (IDH - salud, educación y estándares de vida - sino que perpetúa la condición de desigualdad estructural en que viven las personas con trastornos mentales. Mientras los problemas de salud mental afectan la esperanza de vida, los años de instrucción esperados y el Ingreso Nacional Bruto per cápita, siendo a su vez causa y consecuencia de la pobreza, las personas con trastornos mentales deben enfrentar numerosas barreras para el acceso a la educación, a las oportunidades de empleo y otras fuentes de generación de ingresos, debido a la estigmatización, discriminación y marginación que históricamente han vivido. Por tanto, si queremos que todos sean partícipes de las oportunidades de desarrollo, es necesario un cambio estructural donde desaparezca el estigma frente a los trastornos mentales, que permita posicionar la salud mental como eje de los planes de desarrollo y aumentar la inversión en la promoción de la salud mental y la prevención e

  20. Dosimetric verification of IMRT plans

    International Nuclear Information System (INIS)

    Bulski, W.; Cheimicski, K.; Rostkowska, J.

    2012-01-01

    Intensity modulated radiotherapy (IMRT) is a complex procedure requiring proper dosimetric verification. IMRT dose distributions are characterized by steep dose gradients which enable to spare organs at risk and allow for an escalation of the dose to the tumor. They require large number of radiation beams (sometimes over 10). The fluence measurements for individual beams are not sufficient for evaluation of the total dose distribution and to assure patient safety. The methods used at the Centre of Oncology in Warsaw are presented. In order to measure dose distributions in various cross-sections the film dosimeters were used (radiographic Kodak EDR2 films and radiochromic Gafchromic EBT films). The film characteristics were carefully examined. Several types of tissue equivalent phantoms were developed. A methodology of comparing measured dose distributions against the distributions calculated by treatment planning systems (TPS) was developed and tested. The tolerance level for this comparison was set at 3% difference in dose and 3 mm in distance to agreement. The so called gamma formalism was used. The results of these comparisons for a group of over 600 patients are presented. Agreement was found in 87 % of cases. This film dosimetry methodology was used as a benchmark to test and validate the performance of commercially available 2D and 3D matrices of detectors (ionization chambers or diodes). The results of these validations are also presented. (authors)

  1. Dosimetric approaches: pregnancy and lactation

    International Nuclear Information System (INIS)

    Rojo, Ana M.

    2001-01-01

    The female nuclear medicine patient is of special concern to the evaluation of radiation dose since radiation protection point of view: a)- The females overall body size and organ sizes are generally smaller than those of her male counterpart (thus her radiation doses will be higher, given the same amounts of administered activity and similar biokinetics), the effective doses could be 25 per cent higher than a man; b)- Female gonads are inside the body instead of outside and are near several organs often important as source organs in internal dosimetry; female gonads doses could be up to 10 or 30 higher than male gonads (usually 3 order); c)- Risk of breast cancer is significantly higher among females than males; d)- During the pregnancy due to placental transfer of radiopharmaceuticals or radiation exposure from the urinary bladder the embryo/fetus could receive doses that must be avoid; e)- In the case of nursing infant is of special concern in such an analysis to determine the interruption period to avoid doses in the nursing infant. The dosimetric approaches to take account to assess internal doses in the pregnant woman and during the breast feeding are discussed. (author)

  2. Development of materials with dosimetric applications

    International Nuclear Information System (INIS)

    Mendoza A, D.; Perez H, R.; Gonzalez, P.R.; Estrada G, R.; Salas C, P.

    2003-01-01

    The thermoluminescence (Tl) is a property that have certain materials, of emitting light thermally stimulated, when they have been exposed to a field of ionizing radiation. In this work an analysis of the Tl response induced by the gamma radiation in the zircon, titania and hydroxyapatite is presented. First the influence of the presence of graphite in the Tl response of the zircon is analyzed, next the sensitivity of the titania thermally treated to different temperatures is analyzed. Finally the Tl response produced by the hydroxyapatite synthesized by two different processes is studied. (Author)

  3. Dosimetric characteristics of a TLD dosemeter with extremities

    International Nuclear Information System (INIS)

    Molina P, D.; Diaz B, E.; Lien V, R.

    1999-01-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm 3 covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  4. Organizaciones sociales y desarrollo local

    Directory of Open Access Journals (Sweden)

    Luis Inostroza Fernández

    2010-01-01

    Full Text Available En este trabajo se analizan dos temas de gran interés: por una parte, las organizaciones sociales y, por la otra, el desarrollo local, ambas tienen relación directa con la política de desarrollo. Estos temas estarán presentes en todo el desarrollo del presente texto. En este siglo XXI la política de desarrollo estaá muy condicionada por las relaciones internacionales de lucha contra la pobreza; tendrá que aumentar la ayuda internacional en casos de hambrunas y catástrofes, producto del calentamiento global, así como del problema de la migración, las guerras locales y el peligro de una guerra global. La idea es no seguir con el desarrollo con destrucción. La política de desarrollo debe dar soluciones para los países pobres y ricos; ello exige un análisis especial de las megatendencias: globalización, transnacionalización y regionalización, tres escenarios claves del mundo contemporáneo que nos hacen pensar en una forma de soluciones planetarias, que favorezcan el desarrollo de una capacidad de gobierno a escala mundial; es decir, una gobernanza global que actúe en las coyunturas conflictivas, en situaciones de guerras locales y ante el problema del calentamiento global (manejo de una capacidad de gobierno global, una gobernabilidad activa y un proyecto de gobierno mundial.

  5. Study of dosimetric systems-ferrous sulfate-ferric sulfate, glass slides and dyed aqueous solutions

    International Nuclear Information System (INIS)

    Fernandes, L.

    1979-01-01

    The effect of some variables which can effect the preparation of the ferrous sulfate used as dosimetric solution has been studied. Among these variables the purity of the water used for the preparation of the solution and the presence (or absence) of oxygen in the dosimetric solution were considered. The dose rate distribution according to the transverse and longitudinal sections of the Co 60 irradiator was studied experimentally, using the dosimetric solution, and theoretically, using a computer program (KIFE). The results obtained with the ferrous sulface dosimetric solution were used as reference for the study of the application of EM and MSG glass slide as a dosimetric system. For this purpose the effects of the weakening of the coloration induced in the glass by gamma rays (Co 60 ) and the relationship between the absorbed dose of radiation and the ratio between the variation in absorbation value and the thickness of the glass irradiated, were studied. A study was also made of the use of the dye indicators bromothymol-blue, methyl-orange, Congo-red, neutral-red and p-nitrophenol, in aqueous solution, for radiation dose measurements. The bleaching of each indicator solution, under gamma-radiation (Co 60 ) was studied in oxygen and nitrogen atmospheres.(Author) [pt

  6. Revision of the dosimetric parameters of the CSM11 LDR Cs-137 source.

    Science.gov (United States)

    Otal, Antonio; Martínez-Fernández, Juan Manuel; Granero, Domingo

    2011-03-01

    The clinical use of brachytherapy sources requires the existence of dosimetric data with enough of quality for the proper application of treatments in clinical practice. It has been found that the published data for the low dose rate CSM11 Cs-137 source lacks of smoothness in some regions because the data are too noisy. The purpose of this study was to calculate the dosimetric data for this source in order to provide quality dosimetric improvement of the existing dosimetric data of Ballester et al . [1]. In order to obtain the dose rate distributions Monte Carlo simulations were done using the GEANT4 code. A spherical phantom 40 cm in radius with the Cs-137 source located at the centre of the phantom was used. The results from Monte Carlo simulations were applied to derive AAPM Task Group 43 dosimetric parameters: anisotropy function, radial dose function, air kerma strength and dose rate constant. The dose rate constant obtained was 1.094 ± 0.002 cGy h -1 U -1 . The new calculated data agrees within experimental uncertainties with the existing data of Ballester et al . but without the statistical noise of that study. The obtained data presently fulfills all the requirements of the TG-43U1 update and thus it can be used in clinical practice.

  7. Monte Carlo generation of dosimetric parameters for eye plaque dosimetry

    International Nuclear Information System (INIS)

    Cutajar, D.L.; Green, J.A.; Guatelli, S.; Rosenfeld, A.B.

    2010-01-01

    Full text: The Centre for Medical Radiation Physics have undertaken the dcvelopment of a quality assurance tool, using silicon pixelated detectors, for the calibration of eye plaques prior to insertion. Dosimetric software to correlate the measured and predicted dose rates has been constructed. The dosimetric parameters within the software, for both 1-125 and Ru-I 06 based eye plaques, were optimised using the Geant4 Monte Carlo toolkit. Methods For 1-125 based plaques, an novel application was developed to generate TG-43 parameters for any seed input. TG-43 parameters were generated for an Oncura model 6711 seed, with data points every millimetre up to 25 mm in the radial direction, and every 5 degrees in polar angle, and correlated to published data. For the Ru106 based plaques, an application was developed to generate dose rates about a Bebig model CCD plaque. Toroids were used to score the deposited dose, taking advantage of the cylindrical symmetry of the plaque, with radii in millimetre increments up to 25 mm, and depth from the plaque surface in millimetre increments up to 25 mm. Results TheTG43 parameters generated for the 6711 seed correlate well with published TG43 data at the given intervals, with radial dose function within 3%, and anisotropy function within 5% for angles greater than 30 degrees. The Ru-l 06 plaque data correlated well with the Bebig protocol of measurement. Conclusion Geant4 is a useful Monte Carlo tool for the generation of dosimetric data for eye plaque dosimetry. which may improve the quality assurance of eye plaque treatment. (author)

  8. Applichation of the sulphate ceric dosimetric in the high doses range

    International Nuclear Information System (INIS)

    Prieto Miranda, F.

    1991-01-01

    The ceric-cerous dosimetric system is one of the system more employed in the high dose dosimetry. The spectrophotometric procedure to measure the ceric-concentration is an usual analityc method to determine the absorbed dose. On the other hand, due at increase employ of the irradiation process control. In this paper is realized the ceric-cerous dosimetric calibration in the dose range of 0,6 - 5 kGy and the application in the irradiation process control to differents absorbed dose values

  9. Institucionalidad y desarrollo rural

    Directory of Open Access Journals (Sweden)

    Laureano Ruiz Camargo

    2016-04-01

    Full Text Available La institucionalidad entendida como el conjunto de normas y reg las formales e informales que regulan una comunidad determinada puede influir al impulsar y acrecentar el desarrollo rural o también frenarlo, permitiendo o no la participación o también obstaculizando la organización y la expresión de las comunidades rurales; lo cual puede reflejarse en carencias de sentido económico, social y cultural. Estas temáticas han sido exploradas en el presente trabajo, mediante el contacto directo con las comunidades rura les del municipio de Paipa (Boyacá y complementado con la revisión teórica a nivel bibliográfica sobre los temas de la institucionalidad y el desarrollo rural sustentable. Dada la importancia de las familias campesinas asentadas en estos territorios de minifundios y economía campesina, en la reproducción de su propia subsistencia y el aporte a la producción de bienes para la alimentación de la población urbana y suministro de mano de obra necesaria en la prestación de servicios y la industria nacional, se encontró que las carencias de tipo económico y social por parte de la población se reflejan en índices de pobreza elevada, debido a la poca capacidad de consumo y acumulación, pues la propiedad privada sustentada en el minifundio utilizado en actividades agropecuarias no genera ingresos suficientes para financiar la alimentación, la educación, la salud, la vivienda, la recreación y tampoco posibilita el ahorro. Por otra parte, la producción de bienes y servicios de origen rural es vendida o intercambiada en el mercado a precios por debajo de los costos de producción, con lo cual se transfiere la riqueza producida en el campo hacia la ciudad, reproduciéndose el circulo de la pobreza rural donde la institucionalidad practicada y existente no permite la participación de los habitantes rurales en la toma de decisiones; entre otras cosas, porque carecen de organización y liderazgo y porque tradicionalmente la

  10. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    International Nuclear Information System (INIS)

    Shpotyuk, O.

    1997-01-01

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author)

  11. Los objetivos del desarrollo

    Directory of Open Access Journals (Sweden)

    Currie Lauchlin

    1993-12-01

    Full Text Available To broach the goals of development implies broaching the problem of economic growth in a critical manner. Not only the concept of growth but also the means of achieving it in practice should be questioned. Growth is not an end, it is a means of gaining access to development And development should not be understood as a goal, but as a permanent process of learning tending towards more control over the environment and greater levels of well-being. It is not a matter of increasing GNP linearly; development must occur, sustained growth that, without being a threat to mm or to our natural resources, can lead to the eradication of absolute and relati.ve poverty. The low rates of growth of the developing countries constitute structural problem that can /lot be reso1.ved by resorting to the neo-classical mechanisms of mobility, nor to the Keynesian formulas. These have served as a source of inspiration to the Harrod-lX:m3r·type models of growth which limit themselves to stimulating savings and ending unemployment by concentrating exclusively on the monetary demand. Getting OUt of the vicious circle of low growth implies eradicating poverty with respect into the immediateness of a direct attack on the problem. with respect to the developed counties, growth is starting to became harmful, and, given the prevalence of ostensible consumption and of pecuniary emulation, it is imperative to foment non-economic motivation that will permit the eradication of relative poverty.

    Abordar los objetivos del desarrollo implica abordar de manera crítica el problema del crecimiento econ

  12. democracia, pobreza y desarrollo

    Directory of Open Access Journals (Sweden)

    Esperanza Gómez Hernández

    2007-01-01

    Full Text Available Este artículo presenta los aspectos centrales de la evaluación del Presupuesto Participativo realizada entre los años 2005-2006 en Medellín (Colombia, para la vigencia fiscal del 2005. Mediante la consulta a diversos estamentos de la sociedad política, civil y administrativa de la ciudad, se logró hacer un balance de la gobernabilidad democrática y la participación, la planeación y el desarrollo local, y la gestión pública, sintetizados en tres niveles: el operativo-funcional, el metodológico-normativo y el estratégicopolítico. La discusión final trata asuntos críticos del Presupuesto Participativo en cuanto a las transformaciones en el poder local, el tejido social y la superación de la pobreza, y retoma los acercamientos a otras experiencias de América Latina y los informes de la administración municipal y la veeduría de Medellín.

  13. DESARROLLO, GLOBALIZACION E INTEGRACION FRONTERIZA

    Directory of Open Access Journals (Sweden)

    Fernando Bedoya Barco

    2000-05-01

    Full Text Available Se comienza con una breve referencia a la evolución que ha tenido el concepto “Desarrollo Económico” destacando la influencia de los modos de inserción internacional en el concepto y en la trayectoria del desarrollo económico de América Latina. Se destacan los principales aspectos que marcaron la crisis del modelo de desarrollo adoptado y las medidas de política económica propuestas por el F.M.I. , el Banco Mundial y después, por el denominado “consenso de Washington” , para superar la crisis y poner en marcha un nuevo modelo que, en lo fundamental, se basa en utilizar los mecanismos de mercado como estrategia apropiada para el desarrollo. En este marco se menciona el fracaso de la estrategia de integración económica Regional originado, entre otras razones, por el mismo modelo de desarrollo adoptado. Se hace una referencia al aspecto de la integración fronteriza para señalar la ineficiencia de las estrategias adoptadas en este sentido en contraste con la claridad del diagnóstico elaborado en su oportunidad por el B.I.D. Se aborda este aspecto con el fin de enfatizar la posibilidad de un desarrollo regional desde una perspectiva binacional fronteriza.

  14. Internal dosimetric evaluation due to uranium aerosols

    International Nuclear Information System (INIS)

    Garcia Aguilar Juan; Delgado Avila Gustavo

    1991-01-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research

  15. ESR dosimetric properties of some biomineral materials

    International Nuclear Information System (INIS)

    Hassan, Gamal M.; Sharaf, M.A.

    2005-01-01

    Dosimetric properties of g-irradiated modern coral and bioactive glass (Bio-G) samples analyzed with electron spin resonance (ESR) have been separately reported (Hassan et al., 2004; Sharaf and Hassan, 2004) and compared with alanine. These are combined here to allow a three-way comparison between these materials

  16. ESR dosimetric properties of some biomineral materials

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Gamal M. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street, El-Haram, El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)]. E-mail: gamalhassan65@hotmail.com; Sharaf, M.A. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street, El-Haram, El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)

    2005-02-01

    Dosimetric properties of g-irradiated modern coral and bioactive glass (Bio-G) samples analyzed with electron spin resonance (ESR) have been separately reported (Hassan et al., 2004; Sharaf and Hassan, 2004) and compared with alanine. These are combined here to allow a three-way comparison between these materials.

  17. Cytogenetic Dosimetry: Applications in Preparedness for and Response to Radiation Emergencies (Spanish Edition); Dosimetría citogenética: Aplicaciones en materia de preparación y respuesta a las emergencias radiológicas

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-10-15

    Cytogenetic dosimetry is recognized as a valuable dose assessment method which fills a gap in dosimetric technology, particularly when there are difficulties in interpreting the data, in cases where there is reason to believe that persons not wearing dosimeters have been exposed to radiation, in cases of claims for compensation for radiation injuries that are not supported by unequivocal dosimetric evidence, or in cases of exposure over an individual’s working lifetime. The IAEA has maintained a long standing involvement in biological dosimetry commencing in 1978. This association has been through a sequence of coordinated research programmes (CRPs), the running of regional and national training courses, the sponsorship of individual training fellowships, and the provision of equipment to laboratories in Member States, establishing capabilities in biological dosimetry. From this has arisen the provision to Member States of advice regarding the best focus for research and suggestions for the most suitable techniques for future practice in biological dosimetry. One CRP resulted in the publication in 1986 of a manual, entitled Biological Dosimetry: Chromosomal Aberration Analysis for Dose Assessment (Technical Reports Series No. 260). This was superseded in 2001 by a revised second edition, Technical Reports Series No. 405. This present publication constitutes a third edition, with extensive updating to reflect the considerable advances that have been made in cytogenetic biological dosimetry during the past decade.

  18. A Monte Carlo dosimetric quality assurance system for dynamic intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    Takegawa, Hideki; Yamamoto, Tokihiro; Miyabe, Yuki; Teshima, Teruki; Kunugi, Tomoaki; Yano, Shinsuke; Mizowaki, Takashi; Nagata, Yasushi; Hiraoka, Masahiro

    2005-01-01

    We are developing a Monte Carlo (MC) dose calculation system, which can resolve dosimetric issues derived from multileaf collimator (MLC) design for routine dosimetric quality assurance (QA) of intensity-modulated radiotherapy (IMRT). The treatment head of the medical linear accelerator equipped with MLC was modeled using the EGS4 MC code. A graphical user interface (GUI) application was developed to implement MC dose computation in the CT-based patient model and compare the MC calculated results with those of a commercial radiotherapy treatment planning (RTP) system, Varian Eclipse. To reduce computation time, the EGS4 MC code has been parallelized on massive parallel processing (MPP) system using the message passing interface (MPI). The MC treatment head model and MLC model were validated by the measurement data sets of percentage depth dose (PDD) and off-center ratio (OCR) in the water phantom and the film measurements for the static and dynamic test patterns, respectively. In the treatment head model, the MC calculated results agreed with those of measurements for both of PDD and OCR. The MC could reproduce all of the MLC dosimetric effects. A quantitative comparison between the results of MC and Eclipse was successfully performed with the GUI application. Parallel speed-up became almost linear. An MC dosimetric QA system for dynamic IMRT has been developed, however there were large dose discrepancies between the MC and the measurement in the MLC model simulation, which are now being investigated. (author)

  19. Thermoluminescence dosimetric characteristics of thulium doped ZnB2O4 phosphor

    International Nuclear Information System (INIS)

    Annalakshmi, O.; Jose, M.T.; Madhusoodanan, U.; Subramanian, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

    2014-01-01

    Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10 3 Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB 2 O 4 lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out

  20. Thermoluminescence dosimetric characteristics of thulium doped ZnB{sub 2}O{sub 4} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Annalakshmi, O. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Madhusoodanan, U. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Subramanian, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India); Venkatraman, B. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India)

    2014-02-15

    Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10{sup 3} Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB{sub 2}O{sub 4} lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out.

  1. Biologic data, models, and dosimetric methods for internal emitters

    International Nuclear Information System (INIS)

    Weber, D.A.

    1990-01-01

    The absorbed radiation dose from internal emitters has been and will remain a pivotal factor in assessing risk and therapeutic utility in selecting radiopharmaceuticals for diagnosis and treatment. Although direct measurements of absorbed dose and dose distributions in vivo have been and will continue to be made in limited situations, the measurement of the biodistribution and clearance of radiopharmaceuticals in human subjects and the use of this data is likely to remain the primary means to approach the calculation and estimation of absorbed dose from internal emitters over the next decade. Since several approximations are used in these schema to calculate dose, attention must be given to inspecting and improving the application of this dosimetric method as better techniques are developed to assay body activity and as more experience is gained in applying these schema to calculating absorbed dose. Discussion of the need for considering small scale dosimetry to calculate absorbed dose at the cellular level will be presented in this paper. Other topics include dose estimates for internal emitters, biologic data mathematical models and dosimetric methods employed. 44 refs

  2. Dosimetric analysis of radiation sources to use in dermatological lesions

    International Nuclear Information System (INIS)

    Tada, Ariane

    2010-01-01

    Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures. Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

  3. Sistemas ubiquos: desarrollo y aplicaciones

    OpenAIRE

    Ramón, Hugo Dionisio; Charne, Javier; Di Cicco, Carlos; Riva, Diego Germán de la; Smail, Ana; Osella Massa, Germán Leandro

    2013-01-01

    Se presenta un proyecto de investigación aplicada al cómputo ubiquo (ubicomp), abarcando aspectos que van desde los fundamentos del desarrollo (técnicas de Ingeniería de requerimientos, metodologías de gestión, desarrollo de proyectos, técnicas de planificación, métricas, normas de calidad, redes de sensores y algoritmos inteligentes y procesamiento de señales) hasta la concepción de aplicaciones específicas orientadas a los procesos productivos de la región y el país, procesos de egobierno y...

  4. SU-G-TeP2-15: Feasibility Study of Fiber-Optic Cerenkov Radiation Sensors for in Vivo Measurement: Dosimetric Characterization and Clinical Application in Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Lah, J [Myongji Hospital, Goyang-si (Korea, Republic of); Son, J [Korea University, Seoul (Korea, Republic of); Kim, G [University of California, San Diego, La Jolla, CA (United States); Shin, D [National Cancer Center, Goyang-si (Korea, Republic of)

    2016-06-15

    Purpose: To evaluate the possibility of a fiber-optic Cerenkov radiation sensor (FCRS) for in vivo dose verification in proton therapy. Methods: The Cerenkov radiation due to the proton beam was measured using a homemade phantom, consisting of a plastic optical fiber (POF, PGSCD1001-13-E, Toray, Tokyo, Japan) connected to each channel of a multianode photomultiplier tube (MAPMT:H7546, Hamamatsu Photonics, Shizuoka, Japan). Data were acquired using a multi-anode photomultiplier tube with the NI-DAQ system (National Instruments Texas, USA). The real-time monitoring graphic user interface was programmed using Labview. The FCRS was analyzed for its dosimetrics characteristic in proton beam. To determine the accuracy of the FCRS in proton dose measurements, we compared the ionization chamber dose measurements using a water phantom. We investigated the feasibility of the FCRS for the measurement of dose distributions near the superficial region for proton plans with a varying separation between the target volume and the surface of 3 patients using a humanoid phantom. Results: The dose-response has good linearity. Dose-rate and energy dependence were found to be within 1%. Depth-dose distributions in non-modulated proton beams obtained with the FCRS was in good agreement with the depth-dose measurements from the ionization chamber. To evaluate the dosimetric accuracy of the FCRS, the difference of isocenter dose between the delivery dose calculated by the treatment planning system and that measured by the FCRS was within 3%. With in vivo dosimetry using the humanoid phantom, the calculated surface doses overestimated measurements by 4%–8% using FCRS. Conclusion: In previous study, our results indicate that the performance of the array-type FCRS was comparable to that of the currently used a multi-layer ion chamber system. In this study, we also believe that the fiber-optic Cerenkov radiation sensor has considerable potential for use with in vivo patient proton dosimetry.

  5. Model dosimetric for Radon and Daughters

    International Nuclear Information System (INIS)

    Puerta, J.A.; Cardenas, H.F.

    1998-01-01

    You elaborates a model dosimetric for radon and their products of decline of short half life starting from the new model of the breathing tract of the publication 66 of the ICRP and the use of the systemic models proposed in the publication 67, 68 and 69 of the same commission. The correlated used methodology the incorporation of these radionuclides with the activity in organs and you excrete, considering the difference of metabolic behavior of the products of decline and of their predecessor

  6. Dosimetric characterization of KMgF3:Tb+PTFE

    International Nuclear Information System (INIS)

    Ramirez R, M. I.; Garcia S, L.; Villicana M, M.; Huirache A, R.; Apolinar C, J.; Gonzalez M, P. R.

    2017-10-01

    In this work the results obtained from the dosimetric characterization of the new radiation detectors of KMgF 3 :Tb+PTFE are presented. The host salt was obtained by means of the microwave technique, with the polycrystalline powder obtained, dosimeters were made in tablet form, using as Ptfe binder. The thermoluminescent response of these new detectors presented a linear behavior, in the dose range between 1 and 1000 Gy of 60 Co gamma radiation, the reproducibility test in the measurements, during ten cycles of heat treatment, irradiation and reading presented ± 3.7% Ds, in the stability test of thermoluminescent signal, during two months showed that the fading is practically null. Due to the results obtained, this new detector could be very useful for the dosimetry of ionizing radiation in different clinical applications. (Author)

  7. Dosimetric systems developed in Brazil for the radiation processes quality control

    International Nuclear Information System (INIS)

    Galante, Ana Maria Sisti; Campos, Leticia Lucente

    2011-01-01

    In order to apply new technologies to the industrial processing of materials aiming economy, efficiency, speed and high quality, ionizing radiation has been used in medicine, archaeology, chemistry, food preservation and other areas. For this reason, the dosimetry area looks for improve current dosimeters and develop new materials for application on quality control of these processes. In Brazil, the research in the dosimetry area occurs with great speed providing many different dosimetric systems. The chemical dosimetry is the most used technique in routine dosimetry, which requires fast and accurate responses. This technique involves determination of absorbed dose by measuring chemical changes radiation induced in the materials. Different dosimetric systems were developed at IPEN for application on radiation process quality and all of them present excellent results; the low cost of these materials allows a more effective dose control, therefore, a larger area or volume can be monitored. (author).

  8. Application of the Voxeldose software for dosimetric evaluation on the thyroid during thorax-AP irradiation considering the peak voltages (k Vp) most used in diagnostic X-ray

    International Nuclear Information System (INIS)

    Vieira, I.F.; Vieira, J.W.; Leal Neto, V.

    2009-01-01

    The evaluation of the absorbed dose distribution can be obtained through a computational model of exposures (ECM), being one the main difficulties at the specific dosimetric evaluation such as the radiodiagnostic, coupling the Monte Carlo computer code, developed for general use, to a anthropomorphic model. This problem can be solved by the software used in this paper, the VoxelDose, and it consists of an algorithm for X-ray diagnostic sources with the Monte Carlo EGS4 code coupled to the voxel anthropomorphic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel). The graphic interface allows the user to insert the mos common exams parameters, and to execute the simulation, obtaining conversion coefficients and the estimative of the deposited energy on organs/tissues radio sensible during the routine procedures. The data obtained were organized into graphics showing the thyroid equivalent dose, which is a radio sensible with 20 g mass and a weight factor of 5 %, compared with the effective dose during an irradiation of thorax-AP

  9. Verification system development a dosimetric tridimensional using Solution Fricke gel in the application for verification of radiation therapy in arc modulated volumetric (VMAT) in treatment with target moving for breathing

    International Nuclear Information System (INIS)

    Sakuraba, Roberto Kenji

    2015-01-01

    Volumetric Modulated Arc Therapy (VMAT) is one of the methods most commonly used in teletherapy to treat cancer. The various technological advances and the evolution of treatment techniques made the VMAT as one of the state of the art methods for the treatment of some cancers. Part of this improvement is credited to improvements in accuracy and prescription dose absorbed recommended to the patient over the years. This advance allows currently is possible to perform dosimetric calculations by means of the computerized planning system, considering the heterogeneity of patients, such as tissues and organs with different water compositions medium (reference radiation), and individual patient contour the movement of tumors breathing. Such advances require quality control of these tools, in order to ensure that the entire treatment process is satisfactory and accurate. Up to now, the community lacks an experimental system capable of evaluating, considering the uncertainty levels if the computerized planning systems are able to consider the movement of targets in the treatments with VMAT. In this paper, will be presented the results obtained with the phantom Fricke Xylenol Gel, capable of measuring the differences introduced by movement using the Magnetic Resonance Image - MRI and compared qualitatively and quantitatively. The main stages of the phantom development, their experimental results, conclusions and comparisons with other systems are discussed. (author)

  10. Dosimetric monitoring at time of Chernobyl clean-up. A retrospective view

    International Nuclear Information System (INIS)

    Chumak, V.V.; Bakhanova, E.V.; Musijachenko, N.V.; Krjuchkov, V.P.

    2000-01-01

    Although at time of the accident many thousands of individuals were subjected to personal dosimetric monitoring, a status of dosimetric support of clean-up activities performed in 1986-1987 remains one of the most uncertain radiological issues related to Chernobyl accident. It is known that the scope, practical coverage and methodologies of dosimetry at time of the accident significantly varied. Unfortunately, the dose records available now in a number registries and databases are lacking direct indications of the methods of dosimetry, locations of work and tasks performed by liquidators. Moreover, data record linkage in many cases is problematic due to lack of unique identifiers in the databases of concern. However, this information, collected in course of dosimetric monitoring is extremely valuable for epidemiological consideration of this cohort and, therefore, cannot be neglected because of problems with strait forward application of this data. Retrospective consideration of dosimetric monitoring data was conducted along several lines. First, data sets (in some cases impersonal), related to the known dosimetric practices were studied in order to determine regularities in their dose distributions, evaluate possible distortions caused by extraneous admixtures to dose arrays and evaluate possible contribution of falsified dose records. Another effort was directed towards individualization of information regarding affiliation and tasks of the liquidators included into the State Chernobyl Registry (SCR), which is, essentially, the main pool of subjects for observation in the framework of post Chernobyl epidemiological studies. The SCR in its original shape was missing this crucial information. In order to recover this information gap, a wide scale postal survey of liquidators was undertaken. Those persons who are included into the State Chernobyl Registry and have official dose records were asked to respond to a simple five-entry questionnaire, dealing with their

  11. Hot pixel generation in active pixel sensors: dosimetric and micro-dosimetric response

    Science.gov (United States)

    Scheick, Leif; Novak, Frank

    2003-01-01

    The dosimetric response of an active pixel sensor is analyzed. heavy ions are seen to damage the pixel in much the same way as gamma radiation. The probability of a hot pixel is seen to exhibit behavior that is not typical with other microdose effects.

  12. Argumentos para repensar el "desarrollo"

    Directory of Open Access Journals (Sweden)

    María Luisa Eschenhagen

    2001-06-01

    Full Text Available Con este trabajo se quiere hacer una aproximación al problema desde una perspectiva diferente, considerando nuevos argumentos que hasta hace muy poco tiempo no se habían tenido en cuenta y que se vienen formulando de una manera muy interesante en los últimos años. El objetivo del artículo es presentar tres argumentos para señalar la necesidad de repensar, desde sus fundamentos, el concepto de desarrollo.

  13. Application of the wavelet ridges method for the estimation of the decay ratio in Boiling Water Reactors; Atomos para el desarrollo de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Prieto G, A.; Espinosa P, G. [UAM-I, 09340 Mexico D.F. (Mexico)

    2008-07-01

    A wavelet ridges application is proposed as a simple method to determine the evolution of the linear stability parameters of a BWR NPP using neutronic noise signals. The wavelets ridges are used to track the instantaneous frequencies contained in a signal and to estimate the Decay Ratio (DR). The first step of the method consists of de noising the analyzed signals by Discrete Wavelet Transform (DWT) to reduce the interference of high-frequency noise and concentrate the analysis in the band where crucial frequencies are presented. Next, is computation of the wavelet ridges by Continuous Wavelet Transform (CWT) to obtain the modulus maxima from the normalized scalogram of the signal. In general, associations with these wavelets ridges can be used to compute instantaneous frequency contained in the signal and the DR evolution with the measurement. To study the performance of the wavelet ridges method, by computing the evolution of the linear stability parameters, both simulated and real neutronic signals were considered. The simulated signal is used to validate methodically and to study some features of the wavelet ridges method. To demonstrate the method applicability a real neutronic signal from the instability event in Laguna Verde was analyzed. The investigations show that most of the local energies of the signal are concentrated in the wavelet ridges and DR variations of the signals were observed along the measurements. (Author)

  14. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

    1997-12-31

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  15. Dosimetric adaptive IMRT driven by fiducial points

    International Nuclear Information System (INIS)

    Crijns, Wouter; Van Herck, Hans; Defraene, Gilles; Van den Bergh, Laura; Haustermans, Karin; Slagmolen, Pieter; Maes, Frederik; Van den Heuvel, Frank

    2014-01-01

    Purpose: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy have become standard treatments but are more sensitive to anatomical variations than 3D conformal techniques. To correct for inter- and intrafraction anatomical variations, fast and easy to implement methods are needed. Here, the authors propose a full dosimetric IMRT correction that finds a compromise in-between basic repositioning (the current clinical practice) and full replanning. It simplifies replanning by avoiding a recontouring step and a full dose calculation. It surpasses repositioning by updating the preoptimized fluence and monitor units (MU) using a limited number of fiducial points and a pretreatment (CB)CT. To adapt the fluence the fiducial points were projected in the beam's eye view (BEV). To adapt the MUs, point dose calculation towards the same fiducial points were performed. The proposed method is intrinsically fast and robust, and simple to understand for operators, because of the use of only four fiducial points and the beam data based point dose calculations. Methods: To perform our dosimetric adaptation, two fluence corrections in the BEV are combined with two MU correction steps along the beam's path. (1) A transformation of the fluence map such that it is realigned with the current target geometry. (2) A correction for an unintended scaling of the penumbra margin when the treatment beams scale to the current target size. (3) A correction for the target depth relative to the body contour and (4) a correction for the target distance to the source. The impact of the correction strategy and its individual components was evaluated by simulations on a virtual prostate phantom. This heterogeneous reference phantom was systematically subjected to population based prostate transformations to simulate interfraction variations. Additionally, a patient example illustrated the clinical practice. The correction strategy was evaluated using both dosimetric

  16. Dosimetric adaptive IMRT driven by fiducial points

    Energy Technology Data Exchange (ETDEWEB)

    Crijns, Wouter, E-mail: wouter.crijns@uzleuven.be [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Van Herck, Hans [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven, 3000 Leuven (Belgium); Defraene, Gilles; Van den Bergh, Laura; Haustermans, Karin [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Slagmolen, Pieter [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven, 3000 Leuven (Belgium); iMinds-KU Leuven Medical IT Department, KU Leuven, 3000 Leuven (Belgium); Maes, Frederik [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven and iMinds, 3000 Leuven (Belgium); Van den Heuvel, Frank [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Department of Oncology, MRC-CR-UK Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford OX1 2JD (United Kingdom)

    2014-06-15

    Purpose: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy have become standard treatments but are more sensitive to anatomical variations than 3D conformal techniques. To correct for inter- and intrafraction anatomical variations, fast and easy to implement methods are needed. Here, the authors propose a full dosimetric IMRT correction that finds a compromise in-between basic repositioning (the current clinical practice) and full replanning. It simplifies replanning by avoiding a recontouring step and a full dose calculation. It surpasses repositioning by updating the preoptimized fluence and monitor units (MU) using a limited number of fiducial points and a pretreatment (CB)CT. To adapt the fluence the fiducial points were projected in the beam's eye view (BEV). To adapt the MUs, point dose calculation towards the same fiducial points were performed. The proposed method is intrinsically fast and robust, and simple to understand for operators, because of the use of only four fiducial points and the beam data based point dose calculations. Methods: To perform our dosimetric adaptation, two fluence corrections in the BEV are combined with two MU correction steps along the beam's path. (1) A transformation of the fluence map such that it is realigned with the current target geometry. (2) A correction for an unintended scaling of the penumbra margin when the treatment beams scale to the current target size. (3) A correction for the target depth relative to the body contour and (4) a correction for the target distance to the source. The impact of the correction strategy and its individual components was evaluated by simulations on a virtual prostate phantom. This heterogeneous reference phantom was systematically subjected to population based prostate transformations to simulate interfraction variations. Additionally, a patient example illustrated the clinical practice. The correction strategy was evaluated using both dosimetric

  17. Postoperative telegammatherapy of breast cancer (Dosimetric studies)

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, J; Mitrov, G [Nauchno-Izsledovatelski Onkologichen Inst., Sofia (Bulgaria); Konstantinov, B; Dobrev, D [Meditsinska Akademiya, Sofia (Bulgaria). Nauchen Inst. po Rentgenologiya i Radiobiologiya

    1977-01-01

    The method employed for postoperative radiation therapy of breast cancer at the Radiologic Clinic of the Medical Academy in Sofia is described. Results are reported and discussed of dosimetric studies carried out with the T-100 on heterogeneous tissue-equivalent Rando phantom for dose distributions in the regional lymph basin and the underlying tissues and organs. The results show coincidence between calculated and measured doses in the regional lymph basin and the thoracic wall. It was demonstrated that maximal radiation loading (3600 to 5500 rad) occurs in the apical and the hilar lung area.

  18. Dosimetric characteristics of LKB:Cu,P solid TL detector

    International Nuclear Information System (INIS)

    Hashim, S.; Alajerami, Y.S.M.; Ghoshal, S.K.; Saleh, M.A.; Saripan, M.I.; Kadir, A.B.A.; Bradley, D.A.; Alzimami, K.

    2014-01-01

    The dosimetric characteristics of newly developed borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and NH 4 H 2 PO 4 are reported. Broad peaks in the absence of any sharp peak confirms the amorphous nature of the prepared glass. A simple glow curve of Cu doped sample is observed with a single prominent peak (T m ) at 220 °C. The TL intensity response shows an enhancement of ∼100 times due to the addition of CuO (0.1 mol%) to LKB compound. A further enhancement of the intensity by a factor of 3 from the addition of 0.25 mol% NH 4 H 2 PO 4 as a co-dopant impurity is attributed to the creation of extra electron traps with consequent increase in energy transfer of radiation recombination centers. The TL yield performance of LKB:Cu,P with Z eff ≈8.92 is approximately seventeen times less sensitive compared to LiF:Mg,Ti (TLD-100). The proposed dosimeter shows good linearity up to 10 3 Gy, minimal fading and photon energy independence. These attractive features offered by our dosimeter is expected to pave the way towards dosimetric applications. - Highlights: • The NH 4 H 2 PO 4 impurities are cross linked with the CuO defect. • The addition of NH 4 H 2 PO 4 as a co-dopant improved the TL intensity by a factor of 3. • The proposed dosimeter shows good linearity up to 10 3 Gy. • Minimal fading and photon energy independence were observed

  19. Historical accounts of the radiation protection- Dosimetric surveillance of L. Berard Center personnel from 1960 to 1988

    International Nuclear Information System (INIS)

    Paoletti, H.

    1990-09-01

    In this thesis, the author describes the discovery of radiations, their first medical applications and first accidents that have been in the beginning of radiation protection and of its development. The author explains how the dosimetric monitoring has been organized at L. Berard Centre in Lyon (France)

  20. ESR dosimetric properties of modern coral reef

    Energy Technology Data Exchange (ETDEWEB)

    Sharaf, M.A. E-mail: mokhtar_sharaf@yahoo.com; Hassan, Gamal M

    2004-06-01

    Modern coral reef samples from Egypt were irradiated with {sup 60}Co{gamma}-rays to study radicals for dosimetric materials with electron spin resonance (ESR). The ESR spectrum for the radical species in unirradiated coral is characterized by four signals with spectroscopic splitting factors of g=2.0056, 2.0030, 2.0006 and 1.997. The signal at g=2.0006{+-}0.0005 is ascribed to free rotation CO{sub 2}{sup -} radicals and used as a dosimetric one. The response to {gamma}-ray doses ranging from 5 to 10{sup 3} Gy and the thermal stability has been studied. The number of free radicals per 100 eV (G-value) was found to be 0.45 {+-} 0.1 and 0.9 {+-} 0.18 for coral and alanine, respectively. The lifetime of radicals and the activation energy were estimated from Arrhenius plots to be approximately 8 x 10{sup 5} {+-} 1.6 x 10{sup 5} years, and 1.12 eV, respectively.

  1. LA HISTORIA SE REPITE: UNA VISIÓN DEL DESARROLLO Y DEL DESARROLLO SOSTENIBLE

    Directory of Open Access Journals (Sweden)

    JAVIER SABOGAL AGUILAR

    2009-01-01

    ha significado mejoras en términos de desarrollo ni de desarrollo sostenible, por lo que se hace urgente la búsqueda de alternativas que respondan a las necesidades latinoamericanas en el marco de una independencia intelectual.

  2. DESARROLLO DE COMPETENCIAS INVESTIGATIVAS EN LOS ESTUDIANTES

    OpenAIRE

    Stalin Fabián Martínez Mora; Fátima René Medina Pinoargote; Luz Angélica Salazar Carranza

    2018-01-01

    En el artículo se expone la necesidad del desarrollo de competencias investigativas en los estudiantes para la formación de profesionales comprometidos con el desarrollo social, al favorecer el desarrollo de habilidades, de valores éticos profesionales y cualidades de la personalidad, como la independencia, la responsabilidad, la creatividad y el compromiso con la profesión seleccionada. Se argumenta la relación entre competencias investigativas y conocimiento, debido a que estas permiten a ...

  3. El desarrollo organizacional innovador: un cambio conceptual para promover el desarrollo

    OpenAIRE

    Elsa Petit Torres

    2012-01-01

    Las concepciones que tradicionalmente han prevalecido sobre el desarrollo organizacional en el marco de la empresa limitan el desarrollo integrado en Latinoamérica. Se propone en este trabajo un nuevo planteamiento conceptual del Desarrollo Organizacional para promover los procesos creativos y transformadores en Latinoamérica. El estudio es de carácter descriptivo-documental, destaca como principales resultados: a) Argumentos que demuestran que el concepto de desarrollo organizacional tradici...

  4. Dosimetric quantities and basic data for the evaluation of generalised derived limits

    International Nuclear Information System (INIS)

    Harrison, N.T.; Simmonds, J.R.

    1980-12-01

    The procedures, dosimetric quantities and basic data to be used for the evaluation of Generalised Derived Limits (GDLs) in environmental materials and of Generalised Derived Limits for discharges to atmosphere are described. The dosimetric considerations and the appropriate intake rates for both children and adults are discussed. In most situations in the nuclear industry and in those institutions, hospitals and laboratories which use relatively small quantities of radioactive material, the Generalised Derived Limits provide convenient reference levels against which the results of environmental monitoring can be compared, and atmospheric discharges can be assessed. They are intended for application when the environmental contamination or discharge to atmosphere is less than about 5% of the Generalised Derived Limit; above this level, it will usually be necessary to undertake a more detailed site-specific assessment. (author)

  5. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  6. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  7. Hacia un desarrollo no convencional

    OpenAIRE

    Múnera López, María Cecilia

    1993-01-01

    Hasta hace relativamente poco tiempo cuando se hablaba de “desarrollo” se aludía únicamente al crecimiento económico dando por supuesto que dicho crecimiento se revierte de manera casi automática en los otros sectores de la estructura social. Las estrategias de desarrollo se han concentrado fundamentalmente en estrategias económicas, que aunque incorporan elementos de otros sectores –por ejemplo del sector social-, buscan como objetivo fundamental el crecimiento económico. Por otra part...

  8. SU-F-T-19: The Consistency Dosimetric Analysis of the Accelerated Breast Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, J; Chandrasekara, S; Pella, S [21st Century Oncology, Boca Raton, FL (United States)

    2016-06-15

    Purpose: To assess the best approach in accept a treatment plan for APBI Savi patients. Should we run a treatment verification test prior to delivering it to the patient? Should we check each CT scan in regards to the initial one in dosimetrical terms? Do we need deformable registration and adaptive planning for each fraction? These are the questions we want to answer running a dosimetric analysis of the dose variances for APBI treatments who receive 10 fractions and no re-planning has been done being considered unnecessary with today’s means of assessment. Methods: A retrospective analysis of 30 patients treated with SAVI applicators were considered for this study. The CT scans taken before each treatment were imported in the treatment planning system and registered with the initial CT scan. The images were fused together with respective to the applicator, using landmark registration. Dosimetric evaluations were performed. Dose received by skin, ribs and PTV on CT images with respect to the initial treatment plan were recorded including maximum, average and minimum dose Results: All the structures displayed changes in volume over the 10 fractions of treatment. The cavities reduction in volume was considerable with a maximum reduction of over 10%. The PTV-eval is covered better due to this fact while the critical organs manifest an increase in the total and maximum dose delivered. Ribs and skin surface that are required by B39 protocol to be monitored can acquire maximum doses of 20% to 30% respectively. Conclusion: A dosimetric evaluation prior to the initial treatment and prior to each of the 10 fractions is proven to be necessary. Deformable registration and adaptive planning have to be studied more and eventually implemented for every patient who received more than one fraction of any type of brachytherapy treatment. Immobilization ad localization methods must be improved and studied further.

  9. Studies on γ-ray induced structural changes in Nd{sup 3+} doped lead alumino silicate glasses by means of thermoluminescence for dosimetric applications in high dose ranges

    Energy Technology Data Exchange (ETDEWEB)

    Sundara Rao, M. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, Guntur, A.P. (India); Gandhi, Y. [Department of Physics, Kakani Venkata Ratnam College, Nandigama 521 185, A.P. (India); Sanyal, Bhaskar [Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Bhargavi, K. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, Guntur, A.P. (India); Piasecki, M. [Institute of Physics, J. Dlugosz University, Ul. Armii Krajowej 13/15, 42-201 Czestochowa (Poland); Veeraiah, N., E-mail: nvr8@rediffmail.com [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, Guntur, A.P. (India)

    2014-12-15

    Graphical abstract: TL glow curves of PbO–SiO{sub 2}:Nd{sup 3+} glasses mixed with different concentrations of Al{sub 2}O{sub 3} exposed to γ-rays of dose 5.0 kGy. - Highlights: • TL studies of Nd{sup 3+} ions doped lead alumino silicate glasses were carried out. • Highest TL output was observed in the glasses mixed with 10 mol% of Al{sub 2}O{sub 3}. • Different mechanisms responsible for TL emission were discussed. • Near linearity of the dose response was observed in the dose range of 1.0–3.0 kGy. • These glasses may be useful as dosimeters in processing perishable food commodities. - Abstract: Thermoluminescence (TL) studies on PbO–Al{sub 2}O{sub 3}–SiO{sub 2}:Nd{sup 3+} glasses mixed with varying concentrations of Al{sub 2}O{sub 3} exposed to γ-rays of dose in the range 0–5.0 kGy were carried out. The TL emission exhibited a dosimetric peak at about 185 °C. The TL output under the glow peak increased with increasing Al{sub 2}O{sub 3} and also with the γ-ray dose. The mechanisms responsible for TL emission and enhancement of TL output with increase in the concentration of Al{sub 2}O{sub 3} were quantitatively discussed in terms of induced structural defects in the vicinity of Nd{sup 3+} ions due to interaction of γ-rays with the glass network in the scenario of varying concentration of Al{sub 2}O{sub 3}. The dose response of these glass samples exhibited linear behavior in the medium dose range viz., 1.0–3.0 kGy. Finally, it is concluded that the glass containing the highest concentration of Al{sub 2}O{sub 3} exhibits high TL output and such glasses are useful for dosimetry in the range 1.0–3.0 kGy and hence these glasses may be useful for dosimetry in such high range of doses required for commercial radiation processing of perishable food commodities to extend their shelf-lives.

  10. Dosimetric evaluation program for dental radiology practices

    International Nuclear Information System (INIS)

    Gregori, B.; Milat, J.; Fernandez, J.; Micinquevich, S.; Andrieu, J.

    1992-01-01

    The preliminary results of a program undertaken to estimate the doses to patients associated with dental radiology practices in Argentine, are presented. Information collected from the search demonstrated that the Dieck and coronal techniques are the most commonly used practices, while all the examinations are performed by using a circular collimator. For both practices, the dosimetric studies were carried out on a Rando Alderson phantom. All dose measurements were made using thermoluminescent detectors LiF and Ca 2 F. In addition, a mathematical model was developed by applying the Monte Carlo method to a MIRD-V phantom. Circular and rectangular collimators were used. Absorbed dose distribution on head and neck, as well as surface dose distribution, were estimated. The comparison of the performance of both collimators shows that the use of the rectangular one allows for a dose reduction of 80%. Besides, a good correlation between the physical and mathematical models applied was found. (author)

  11. Dosimetric management during a criticality accident

    International Nuclear Information System (INIS)

    Lebaron-Jacobs, L.; Fottorino, R.; Racine, Y.; Miele, A.; Barbry, F.; Briot, F.; Distinguin, S.; Le Goff, J.P.; Berard, P.; Boisson, P.; Cavadore, D.; Lecoix, G.; Persico, M.H.; Rongier, E.; Challeton-De Vathaire, C.; Medioni, R.; Voisin, P.; Exmelin, L.; Flury-Herard, A.; Gaillard-Lecanu, E.; Lemaire, G.; Gonin, M.; Riasse, C.

    2008-01-01

    A working group from health occupational and clinical biochemistry services on French sites has issued essential data sheets on the guidelines to follow in managing the victims of a criticality accident. Since the priority of the medical management after a criticality accident is to assess the dose and the distribution of dose, some dosimetric investigations have been selected in order to provide a prompt response and to anticipate the final dose reconstruction. Comparison exercises between clinical biochemistry laboratories on French sites were carried out to confirm that each laboratory maintained the required operational methods for hair treatment and the appropriate equipment for 32 P activity in hair and 24 Na activity in blood measurements, and to demonstrate its ability to rapidly provide neutron dose estimates after a criticality accident. As a result, a relation has been assessed to estimate the dose and the distribution of dose according to the neutron spectrum following a criticality accident. (authors)

  12. A national dosimetric audit of IMRT

    International Nuclear Information System (INIS)

    Budgell, Geoff; Berresford, Joe; Trainer, Michael; Bradshaw, Ellie; Sharpe, Peter; Williams, Peter

    2011-01-01

    Background and purpose: A dosimetric audit of IMRT has been carried out within the UK between June 2009 and March 2010 in order to provide an independent check of safe implementation and to identify problems in the modelling and delivery of IMRT. Methods and materials: A mail based audit involving film and alanine dosimeters was utilized. Measurements were made for each individual field in an IMRT plan isocentrically in a flat water-equivalent phantom at a depth of 5 cm. The films and alanine dosimeters were processed and analysed centrally; additional ion chamber measurements were made by each participating centre. Results: 57 of 62 centres participated, with a total of 78 plans submitted. For the film measurements, all 176 fields from the less complex IMRT plans (including prostate and breast plans) achieved over 95% pixels passing a gamma criterion of 3%/3 mm within the 20% isodose. For the more complex IMRT plans (mainly head and neck) 8/245 fields (3.3%) achieved less than 95% pixels passing a 4%/4 mm gamma criterion. Of the alanine measurements, 4/78 (5.1%) of the measurements differed by >5% from the dose predicted by the treatment planning system. Three of these were large deviations of -77.1%, -29.1% and 14.1% respectively. Excluding the three measurements outside 10%, the mean difference was 0.05% with a standard deviation of 1.5%. The out of tolerance results have been subjected to further investigations. Conclusions: A dosimetric audit has been successfully carried out of IMRT implementation by over 90% of UK radiotherapy departments. The audit shows that modelling and delivery of IMRT is accurate, suggesting that the implementation of IMRT has been carried out safely.

  13. Dosimetric evaluation of proton stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Min, Byung Jun; Shin, Dong Ho; Yoo, Seung Hoon; Jeong, Hojin; Lee, Se Byeong

    2011-01-01

    Surgical excision, conventional external radiotherapy, and chemotherapy could prolong survival in patients with small intracranial tumors. However, surgical excision for meningiomas located in the region of the base of skull or re-resection is often difficult. Moreover, treatment is needed for patients with recurrent tumors or postoperative residual tumors. Conventional external radiotherapy is popular and has significantly increased for treating brain tumors. Stereotactic radiosurgery is an effective alternative treatment technique to microsurgical resection such as benign brain tumor or vestibular Schwannomas. In general, the dose to OAR of 3D conformal plan is lower than that of conformal arc and dynamic conformal arc plans. However, any of OARs was not reached to tolerance dose. Although mean dose of the healthy brain tissue for 3D conformal plan was slightly higher than that of arc plans, the doses of the healthy brain tissue at V10 and V20 were significantly low for dynamic conformal arc plan. The dosimetric differences were the greatest at lower doses. In contrast, 3D conformal plan was better spare at higher doses. In this study, a dosimetric evaluation of proton stereotactic radiosurgery for brain lesion tumors was using fixed and arc beams. A brass block fitted to the PTV structure was modeled for dynamic conformal collimator. Although all treatment plans offer a very good coverage of the PTV, we found that proton arc plans had significantly better conformity to the PTV than static 3D conformal plan. The V20 dose of normal brain for dynamic conformal arc therapy is dramatically reduced compare to those for other therapy techniques.

  14. Monte Carlo simulations and dosimetric studies of an irradiation facility

    Energy Technology Data Exchange (ETDEWEB)

    Belchior, A. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)], E-mail: anabelchior@itn.pt; Botelho, M.L; Vaz, P. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)

    2007-09-21

    There is an increasing utilization of ionizing radiation for industrial applications. Additionally, the radiation technology offers a variety of advantages in areas, such as sterilization and food preservation. For these applications, dosimetric tests are of crucial importance in order to assess the dose distribution throughout the sample being irradiated. The use of Monte Carlo methods and computational tools in support of the assessment of the dose distributions in irradiation facilities can prove to be economically effective, representing savings in the utilization of dosemeters, among other benefits. One of the purposes of this study is the development of a Monte Carlo simulation, using a state-of-the-art computational tool-MCNPX-in order to determine the dose distribution inside an irradiation facility of Cobalt 60. This irradiation facility is currently in operation at the ITN campus and will feature an automation and robotics component, which will allow its remote utilization by an external user, under REEQ/996/BIO/2005 project. The detailed geometrical description of the irradiation facility has been implemented in MCNPX, which features an accurate and full simulation of the electron-photon processes involved. The validation of the simulation results obtained was performed by chemical dosimetry methods, namely a Fricke solution. The Fricke dosimeter is a standard dosimeter and is widely used in radiation processing for calibration purposes.

  15. Dosimetric analysis of radiation sources for use dermatological lesions

    International Nuclear Information System (INIS)

    Tada, Ariane

    2010-01-01

    Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures . Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code were both physically consistent as expected. These experimental measurements compared with calculations using the MCNP-4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

  16. A new fully integrated X-ray irradiator system for dosimetric research

    International Nuclear Information System (INIS)

    Richter, D.; Mittelstraß, D.; Kreutzer, S.; Pintaske, R.; Dornich, K.; Fuchs, M.

    2016-01-01

    A fully housed X-ray irradiator was developed for use within lexsyg or Magnettech desktop equipment. The importance of hardening of the low energy photon radiation is discussed, its performance and feasibility is empirically shown and sustained by basic numerical simulations. Results of the latter for various materials are given for different X-ray source settings in order to provide estimates on the required setup for the irradiation of different geometries and materials. A Si-photodiode provides real-time monitoring of the X-ray-irradiator designed for use in dosimetric dating and other dosimetric application where irradiation of small samples or dosemeters is required. - Highlights: • Bench top X-ray irradiator provides variable dose-rates. • Simulation of low energy photon irradiation and hardening of X-ray. • Al-hardening for the irradiation of H_2O, BeO, Al_2O_3, quartz, feldspars and zircon. • Dosimetric dating equipment for luminescence and ESR.

  17. Dosimetric characteristics of Li2B4O7:Cu,Ag,P solid TL detectors

    International Nuclear Information System (INIS)

    Proki, M.

    2002-01-01

    The main dosimetric characteristics are presented of newly prepared tissue-equivalent, highly sensitive thermoluminescent detector, Li 2 B 4 O 7 :Cu,Ag,P in the form of sintered pellets, developed at the Institute of Nuclear Sciences, Vin a . As a result of an advancement in the preparation procedure by the sensitising of basic copper activated lithium borate TL material, significant improvement in the TL sensitivity of Li 2 B 4 O 7 :Cu,Ag,P was gained. The glow curve of Li 2 B 4 O 7 :Cu,Ag,P consists of well defined main dosimetric peak situated at about 185-190 deg. C with the TL sensitivity which is about four to five times higher than that of LiF:Mg,Ti (TLD-100). From the experimental results a very wide linear dose response range, up to 10 3 Gy is evident. Dosimetric characteristics make sintered solid Li 2 B 4 O 7 :Cu,Ag,P TL detectors very promising for different dosimetry applications particularly in medical dosimetry and also for individual monitoring. (author)

  18. Computerized dosimetric system for studying radiation fields of afterloading apparatus

    International Nuclear Information System (INIS)

    Andryushin, O.S.; Gorshkov, M.I.

    1988-01-01

    Works on designing a computerized dosimetric scanner (CODOS) for studying radiation fields of remote therapeutic apparatus, providing dosimetric data input from semiconductor transducers and ionization chambers directly into the computer memory were carried out. The basic problems were to provide reproducibility and accuracy of the initial dosimetric data, formation of the data bank on LUEhV-15M1 accelerator bremsstrahlung and electron radiation fields. An extra problem was to provide isodose curves for manual scheduling of radiotherapy. The 15 VUMS-28-025 complex based on Elektronika-60 computer was chosen as a host computer, photodiodes were used as a semiconductor detector, the 70108 rod chamber and VA-J-18 dosemeters were used as an ionization chamber. The results of studies with the CODOS system have been shown that it meets the dosimetric requirements for therapeutic apparatus

  19. Determination of Absorbed Dose Using a Dosimetric Film

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Badita, E.; Mitru, E.

    2009-01-01

    This paper presents the absorbed dose measurements by means of the irradiated dosimetric reference films. The dose distributions were made by MULTIDATA film densitometer using RTD-4 software, in INFLPR Linear Accelerator Department

  20. Dosimetric characteristics of biological effect of sulfur-35

    International Nuclear Information System (INIS)

    Borisova, V.V.

    1990-01-01

    Experimental materials related to evaluation of dosimetric characteristics of sulfur-35 are presented. Hemogenic organs are subjected to greatest influence especially in the first hours after radionuclide entry into the organism. Comparison is made of absorbed doses in blood with observed blastomogen effect of hemogenic organs. It is noted, that quantitative evaluation of relative biological efficiency of low energy beta-emitters should be performed with account of dosimetric peculiarities of the nuclides mentioned above. 10 refs.; 3 tabs

  1. Radiation process control, study and acceptance of dosimetric methods

    International Nuclear Information System (INIS)

    Radak, B.B.

    1984-01-01

    The methods of primary dosimetric standardization and the calibration of dosimetric monitors suitable for radiation process control were outlined in the form of a logical pattern in which they are in current use on industrial scale in Yugoslavia. The reliability of the process control of industrial sterilization of medical supplies for the last four years was discussed. The preparatory works for the intermittent use of electron beams in cable industry were described. (author)

  2. Computerized tomography in Community of Madrid. Reference dosimetric measurements

    International Nuclear Information System (INIS)

    Ruiz Sanz, S.; Calzado, A.; Melchor, M.; Marco, M.

    1994-01-01

    A total of about 43 computed tomography scanners were operating in the Autonomous Community of Madrid during 1991. A sample of 14 facilities was selected to perform dosimetric measurements in order to obtain characteristic dose profiles. From these, some quantities as the computed tomography dose index and the enhancement factor were calculated and analysed for the most common technique settings. Relations were established between the dosimetric results and technical characteristics of the scanners. (Author)

  3. TV broadcasting para el desarrollo

    Directory of Open Access Journals (Sweden)

    Valerio Fuenzalida

    2015-01-01

    Full Text Available Entre los intentos de producción de televisión masiva con objetivos educativos, conscientizadores, desarrollistas o superadores hay más fracasos que éxitos. El autor propone que esto se debe a la incomprensión, por parte de los productores, de las actitudes y motivaciones de los receptores. Su análisis sobrio llama la atención sobre las características propias del medio y de sus distintos géneros y audiencias. Del análisis se desprende la necesidad de moderar las expectativas y el rechazo de las tesis que niegan al medio todo significado y potencial para el desarrollo. Fuenzalida transforma la tradicional crítica al medio y sus empresas en una llamada de atención a quienes producen es ese contexto.

  4. Crecimiento y desarrollo infantil temprano

    Directory of Open Access Journals (Sweden)

    Melitón Arce

    2015-09-01

    Full Text Available En este artículo se describen y comentan aspectos vinculados con el proceso de crecimiento y desarrollo del niño, poniendo énfasis en los primeros años de vida, periodo en el cual este proceso alcanza velocidad crítica en las estructuras y funciones más importantes de la economía humana. Se reafirma que ello puede contribuir a que la sociedad disponga de una generación cada vez mejor de adultos, los que a su turno serán capaces de contribuir a construir un mundo mejor y dentro de él una sociedad que goce de mayor bienestar. En un primer capítulo se mencionan consideraciones de orden general sobre la evolución favorable de la sociedad de humanos, sustentada en la calidad de sus futuros adultos, lo que equivale a decir de los logros que alcancen sus actuales niños. Un segundo capítulo menciona los aspectos básicos sobre crecimiento y desarrollo, en las diferentes esferas y los diversos fenómenos que en él se dan. En el tercero hacemos referencia a las oportunidades perdidas y los factores negativos que pueden incidir retrasando el proceso y con ello dando lugar a no obtenerse los logros esperados, en el cuarto se presentan las conclusiones y recomendaciones ratificando la concepción inicial de que un buen cuidado temprano del niño sirve para construir una sociedad mejor, y se formulan algunas recomendaciones para hacer del mismo una buena práctica.

  5. Development and application of a methodology for the classification of the operating conditions of power transformers; Desarrollo y aplicacion de una metodologia para la clasificacion del estado operativo de transformadores de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Lara Covarrubias, Hector

    2004-05-15

    This thesis work shows the development of a classification model that allows the user to assess the operative condition of power transformers. The proposed model includes the following steps: Relative weights assignation for each IEEE-62-1995 required test. Those relative weights are obtained from test results and standardized and experience based limits obtained by Comision Federal de Electricidad (CFE). Once the relative weights have been assigned, three states, green, yellow and red were defined. Each state was then ranked with a weight number (1, 2 or 3). Specific weights were assigned for each test included in the model. Test score assignation takes into account the product of the relative value and the specific weight of each test. Transformer risk assessment uses the total score obtained from the sum of the tests partial scores. Transformer risk assessment was then classified in three categories. Total score causes the system to issue maintenance or substitution recommendations. The described model will improve maintenance scheduling according the transformer risk assessment and it is fully applicable to the complete CFE power transformer population. Further, smart investment and substitution plans, can be easily obtained from the model, preventing catastrophic failures that may cause logistic and economical problems to the Mexican Power System operation. As an example, the results obtained from the model application to two transformer banks installed in a CFE hydroelectric power plant were discussed and analyzed. [Spanish] El trabajo que se muestra en esta tesis, es el desarrollo de un modelo para la clasificacion del estado operativo de los transformadores de potencia. El modelo propuesto incluye los siguientes pasos: Asignacion de pesos relativos para cada una de las pruebas establecidas en la norma IEEE-62-1995 en funcion de sus resultados, limites establecidos en la normatividad y limites propuestos con base en la experiencia de la Comision Federal de

  6. Development of optimized dosimetric models for HDR brachytherapy

    International Nuclear Information System (INIS)

    Thayalan, K.; Jagadeesan, M.

    2003-01-01

    High dose rate brachytherapy (HDRB) systems are in clinical use for more than four decades particularly in cervical cancer. Optimization is the method to produce dose distribution which assures that doses are not compromised at the treatment sites whilst reducing the risk of overdosing critical organs. Hence HDRB optimization begins with the desired dose distribution and requires the calculations of the relative weighting factors for each dwell position with out changing the source activity. The optimization for Ca. uterine cervix treatment is simply duplication of the dose distribution used for Low dose rate (LDR) applications. In the present work, two optimized dosimetric models were proposed and studied thoroughly, to suit the local clinical conditions. These models are named as HDR-C and HDR-D, where C and D represent configuration and distance respectively. These models duplicate exactly the LDR pear shaped dose distribution, which is a golden standard. The validity of these models is tested in different clinical situations and in actual patients (n=92). These models: HDR-C and HDR-D reduce bladder dose by 11.11% and 10% and rectal dose by 8% and 7% respectively. The treatment time is also reduced by 12-14%. In a busy hospital setup, these models find a place to cater large number of patients, while addressing individual patients geometry. (author)

  7. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    International Nuclear Information System (INIS)

    Cunha, Elisete L.; Schimitberger, Thiago

    2017-01-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm -1 and 3271 cm -1 , with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  8. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Elisete L.; Schimitberger, Thiago, E-mail: elisete.cunha@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Oliveira, Cristiana M.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm{sup -1} and 3271 cm{sup -1}, with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  9. Dosimetric assessment of swallowing examinations with videofluoroscopy

    International Nuclear Information System (INIS)

    Costa, M.M.B.; Canevaro, L.V.; Azevedo, A.C.P.

    2001-01-01

    Dosimetric analysis measurements of the Dose-Area-Product (DAP) of 7 individuals were estimated for the deglutition dynamic using the videofluoroscopic method. The aim of this study is to establish in a preliminary way, typical DAP values for this kind of study. The DAP values were obtained attaching to the X ray tube exit, an ionization chamber from PTW and a Diamentor M4 meter. The typical DAP values obtained during the videofluoroscopic evaluation of the deglutition dynamic, including its three phases, was: 4101 ± 881 cGy.cm 2 and the typical DAP rate was 577 ± 94 cGy.cm 2 /min. These values refer to a standard patient (1.57 cm height, 56 kg. weight) and a protocol that can be performed in about 7 minutes. The values, defined herein as typical refer to the used protocol. To our knowledge, the mean DAP rate is a good parameter to estimate radiation exposure from videofluoroscopic study of swallowing process. (author)

  10. Dosimetric feature of natural biotite mineral

    International Nuclear Information System (INIS)

    Kalita, J.M.; Wary, G.

    2015-01-01

    A thermoluminescence (TL) study relevant to radiation dosimetry has been carried out for X-ray irradiated biotite mineral under un-annealed and different annealed (473, 573, 673 and 773 K) conditions. Some significant variations in dosimetric characteristics have been observed with annealing treatment. Due to generation of an additional shallow trap level at depth 0.78 eV in 673 and 773 K annealed samples, the dose response is found to improve. For the 773 K annealed sample, a linear dose response has been observed from 10 to 1100 mGy. The fading is ∼13 % within 5 d after irradiation and onward it reduces to 7 % up to 60 d. Reproducibility of this (773 K) sample is excellent. After 10 recycles the coefficient of variations in the results for the 60, 180 and 1000 mGy dose-irradiated samples are found to be 0.97, 1.31 and 1.03 %, respectively. The potential use of biotite as a natural X-ray dosemeter is discussed. (authors)

  11. Chilean Nuclear Energy Commission dosimetric information system

    International Nuclear Information System (INIS)

    Guerrero Vallejos, Patricia Andrea

    1997-01-01

    This thesis discusses the nuclear radiation that people who work with radioactive material is exposed to and its control by the Chilean Nuclear Energy Commission. A full analysis of the System is presented with information about the Commission and the Department of Nuclear and Radiological Safety which runs the System. Ana analysis of the System is presented in order to obtain requirements. Management flow diagrams, the processes involved and current problems experienced by the users are described. A design logic is modeled producing Data Flow Diagrams (DFD). based on this physical design, or, Model of Physical Data, is prepared including tables, attributes, types of data, primary and foreign keys. A description is presented of how the System is implemented, the tools that are used and how the testing phase is carried out. The Dosimetry System meets the criteria for a Software Engineering project, where the basic cycle was used as a working methodology. The System developed supports the dosimetric control of people exposed to radioactive material. (author)

  12. Neutron sources and its dosimetric characteristics

    International Nuclear Information System (INIS)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.; Gallego D, E.; Lorente F, A.

    2005-01-01

    By means of Monte Carlo methods the spectra of the produced neutrons 252 Cf, 252 Cf/D 2 O, 241 Am Be, 239 Pu Be, 140 La Be, 239 Pu 18 O 2 and 226 Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H * (10), H p,sIab (10, 0 0 ), E AP and E ISO . During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of 239 Pu Be and 241 Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  13. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina; Avaliacao dosimetrica de uma combinacao de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porcao distal da vagina

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Roger Guilherme Rodrigues [Real e Benemerita Sociedade Portuguesa de Beneficencia, Sao Paulo, SP (Brazil). Servico de Radioterapia Estereotactica; Carvalho, Heloisa de Andrade; Stuart, Silvia Radwanski; Rubo, Rodrigo Augusto [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Servico de Radioterapia], e-mail: handrade@hcnet.usp.br; Seraide, Rodrigo Migotto [Centro de Oncologia Campinas, SP (Brazil)

    2009-07-15

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  14. Desarrollo de Mooc en Facebook

    Directory of Open Access Journals (Sweden)

    Carlos Bravo Reyes

    2015-04-01

    Full Text Available Los cursos masivos, abiertos y en línea (MOOC constituyen un modo de capacitación no formal para millones de personas que se inscriben dentro del proceso de formación permanente que es propio de la sociedad actual. La mayoría de estos cursos se desarrollan en plataformas que mantienen un carácter vertical en la relación entre los organizadores de los cursos y sus participantes. El artículo describe el desarrollo de dos MOOC que emplean Facebook, la metodología propia para este tipo de curso en dicha plataforma y la manera de involucrar a los estudiantes de trabajo final de grado de la licenciatura en Educación de nuestra Universidad en los dos MOOC y que asumen el papel de profesores. Los resultados obtenidos, parte de los cuales son analizados en el trabajo, demostraron que los principales problemas en este tipo de curso son los mismos que presentan otros cursos que tienen lugar en otras plataformas.

  15. Sustentabilidad del desarrollo, precisiones conceptuales.

    Directory of Open Access Journals (Sweden)

    Luis Duquino

    2015-07-01

    Full Text Available El presente texto forma parte de la investigación Transformaciones de la Política Pública Ambiental para el Ordenamiento Territorial de Bogotá: una revisión a la gestión ambiental urbana en el marco del neoliberalismo y la globalización (1990-2012 que tiene como propósito formular lineamientos para la proposición y gestión de dichas políticas garantizando la sustentabilidad del espacio geográfico que sirve de soporte a la vida urbana a partir de la valoración crítica de la normativa generada en el periodo de estudio. En tal sentido, con este artículo se precisa un marco para desarrollar los conceptos asociados a la generación de políticas ambientales, a su impacto sobre la planeación y la gestión del entorno urbano, y como plataforma de la valoración propuesta. Estos conceptos están asociados a la discusión planteada por el Desarrollo Sostenible y su crítica.

  16. Dosimetric analysis of SMD phototransistor in dental phantom of different geometries

    International Nuclear Information System (INIS)

    Belinato, W.; Magalhaes, C. M. S.; Souza, D. N.; Santos, L. A. P.

    2009-10-01

    A commercial surface mount device (SMD) phototransistor, OP520, was inserted in two dental phantoms for dosimetric analysis. The irradiations were accomplished in a dental x-ray equipment of 80 kV using different exposition times. A standard ionization chamber was irradiated at the same conditions and the air kerma measured with it was compared with the electrical charge evaluated by the phototransistor. The results showed satisfactory correspondence among the detectors readings. Moreover, the phototransistor showed up quite sensitively for dental applications, allowing verifying the variations for the different phantoms configurations. (Author)

  17. The revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

    International Nuclear Information System (INIS)

    Bair, W.J.

    1992-05-01

    A task group has revised the dosimetric model of the respiratory tract used to calculate annual limits on intake of radionuclides. The revised model can be used to project respiratory tract doses for workers and members of the public from airborne radionuclides and to assess past exposures. Doses calculated for specific extrathoracic and thoracic tissues can be adjusted to account for differences in radiosensitivity and summed to yield two values of dose for the respiratory tract that are applicable to the ICRP tissue weighted dosimetry system

  18. Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

    International Nuclear Information System (INIS)

    Alajerami Yasser Saleh Mustafa; Hashim Suhairul; Ramli Ahmad Termizi; Saleh Muneer Aziz; Kadir Ahmad Bazlie Bin Abdul; Saripan, Mohd. Iqbal

    2013-01-01

    We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 10 3 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications

  19. Dosimetric characteristics of a TLD dosemeter with extremities; Caracteristicas dosimetricas de un dosimetro TLD de extremidades

    Energy Technology Data Exchange (ETDEWEB)

    Molina P, D.; Diaz B, E.; Lien V, R. [Centro de Proteccion e Higiene de las Radiaciones, CPHR, Apdo.Postal 6195, Habana 6, CP 10600, Ciudad Habana (Cuba)

    1999-07-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm{sup 3} covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  20. Dosimetric methodology for extremities of individuals occupationally exposed to beta radiation using the optically stimulated luminescence technique

    International Nuclear Information System (INIS)

    Pinto, Teresa Cristina Nathan Outeiro

    2010-01-01

    A dosimetric methodology was established for the determination of extremity doses of individuals occupationally exposed to beta radiation, using Al 2 O 3 :C detectors and the optically stimulated luminescence (OSL) reader system microStar, Landauer. The main parts of the work were: characterization of the dosimetric material Al 2 O 3 :C using the OSL technique; establishment of the dose evaluation methodology; dose rate determination of beta radiation sources; application of the established method in a practical test with individuals occupationally exposed to beta radiation during a calibration simulation of clinical applicators; validation of the methodology by the comparison between the dose results of the practical test using the OSL and the thermoluminescence (TL) techniques. The results show that both the OSL Al-2O 3 :C detectors and the technique may be utilized for individual monitoring of extremities and beta radiation. (author)

  1. On the use of advanced numerical models for the evaluation of dosimetric parameters and the verification of exposure limits at workplaces.

    Science.gov (United States)

    Catarinucci, L; Tarricone, L

    2009-12-01

    With the next transposition of the 2004/40/EC Directive, employers will become responsible for the electromagnetic field level at the workplace. To make this task easier, the scientific community is compiling practical guidelines to be followed. This work aims at enriching such guidelines, especially for the dosimetric issues. More specifically, some critical aspects related to the application of numerical dosimetric techniques for the verification of the safety limit compliance have been highlighted. In particular, three different aspects have been considered: the dosimetric parameter dependence on the shape and the inner characterisation of the exposed subject as well as on the numerical algorithm used, and the correlation between reference limits and basic restriction. Results and discussions demonstrate how, even by using sophisticated numerical techniques, in some cases a complex interpretation of the result is mandatory.

  2. On the use of advanced numerical models for the evaluation of dosimetric parameters and the verification of exposure limits at workplaces

    International Nuclear Information System (INIS)

    Catarinucci, L.; Tarricone, L.

    2009-01-01

    With the next transposition of the 2004/40/EC Directive, employers will become responsible for the electromagnetic field level at the workplace. To make this task easier, the scientific community is compiling practical guidelines to be followed. This work aims at enriching such guidelines, especially for the dosimetric issues. More specifically, some critical aspects related to the application of numerical dosimetric techniques for the verification of the safety limit compliance have been highlighted. In particular, three different aspects have been considered: the dosimetric parameter dependence on the shape and the inner characterisation of the exposed subject as well as on the numerical algorithm used, and the correlation between reference limits and basic restriction. Results and discussions demonstrate how, even by using sophisticated numerical techniques, in some cases a complex interpretation of the result is mandatory. (authors)

  3. El desarrollo organizacional innovador: un cambio conceptual para promover el desarrollo

    Directory of Open Access Journals (Sweden)

    Elsa Petit Torres

    2012-01-01

    Full Text Available Las concepciones que tradicionalmente han prevalecido sobre el desarrollo organizacional en el marco de la empresa limitan el desarrollo integrado en Latinoamérica. Se propone en este trabajo un nuevo planteamiento conceptual del Desarrollo Organizacional para promover los procesos creativos y transformadores en Latinoamérica. El estudio es de carácter descriptivo-documental, destaca como principales resultados: a Argumentos que demuestran que el concepto de desarrollo organizacional tradicional limita el desarrollo integrado en el continente, especialmente en cuanto a los espacios de participación de los miembros de la empresa, comunidad y otros grupos de interés. Por tanto, se hace necesario el surgimiento de nuevas categorías conceptuales, y b El enfoque conceptual de desarrollo organizacional tradicional debe enfrentarse al problema de la sustitución de la visión capitalista que domina las relaciones de producción, por una lógica que impulse el desarrollo integrado. Se concluye que el desarrollo organizacional innovador como nueva categoría conceptual, constituye una estrategia para generar, desarrollar y sustentar capacidades societales de innovación que fomenten el empoderamiento innovador de los ciudadanos así como su participación en políticas públicas y empresariales.

  4. The dosimetric standards for low and medium energy X-rays; Les references dosimetriques pour les rayons X de basses et moyennes energies

    Energy Technology Data Exchange (ETDEWEB)

    Ksouri, W.; Denoziere, M.; Lecerf, N.; Leroy, E.

    2009-07-01

    The Laboratoire national Henri Becquerel (LNE-LNHB) has developed national dosimetric standards for x-rays of low and medium energies. This article describes these standards which are aimed at applications of radiation protection of workers and patients in the fields of medical diagnosis and industrial x-ray radiation. Developments for contact radiotherapy are also discussed. (author)

  5. Dosimetric essay in dental radiology; Experiencia dosimetrica en radiologia odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Salaberry, M [Ministerio de Industria, Energia y Mineria, Montevideo (Uruguay). Direccion Nacional de Tecnologia Nuclear; Dato Carfagna, A; Rodriguez Dorgia, R [Universidad de la Republica, Facultad de Odontologia , Montevideo (Uruguay)

    1999-12-31

    A neck study was observated in the tiroids glands,laryngeal zone, sensitive organs for the ionizing radiation for increase dental xray exams. Was selected 29th patients with radiography prescription complete (in the Odontology Faculty Clinics Uruguaian). It took radiographies with and without tiroids necklace and apron lead using dosemeters. Dosimetric studies had demonstrated good dose between patients. For measuring the radiation dose have been used TLD thermoluminescence dosimetric and Harshaw 6600 for read it. The thyroids necklace use and odontology postgrading for training course for dentistry was the two recommendations advised

  6. Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mariados, Neil, E-mail: nmariados@ampofny.com [Associated Medical Professionals of New York, Syracuse, New York (United States); Sylvester, John [21st Century Oncology, East Bradenton, Florida (United States); Shah, Dhiren [Western New York Urology Associates, Cancer Care of WNY, Cheektowaga, New York (United States); Karsh, Lawrence [The Urology Center of Colorado, Denver, Colorado (United States); Hudes, Richard [Chesapeake Urology Research Associates, The Prostate Center, Owings Mills, Maryland (United States); Beyer, David [Arizona Oncology Services Foundation, Phoenix, Arizona (United States); Kurtzman, Steven [Urological Surgeons of Northern California, Campbell, California (United States); Bogart, Jeffrey [The Research Foundation of State University of New York, SUNY Upstate Medical University, Syracuse, New York (United States); Hsi, R. Alex [Peninsula Cancer Center, Poulsbo, Washington (United States); Kos, Michael [Urology Nevada, Reno, Nevada (United States); Ellis, Rodney [University Hospitals Case Medical Center, Cleveland, Ohio (United States); Logsdon, Mark [Sutter Health Sacramento Sierra Region, Sutter Institute for Medical Research, Sacramento, California (United States); Zimberg, Shawn [Advanced Radiation Centers of New York, Lake Success, New York (United States); Forsythe, Kevin [Oregon Urology Institute, Springfield, Oregon (United States); Zhang, Hong [University of Rochester, Rochester, New York (United States); Soffen, Edward [CentraState Medical Center, Freehold, New Jersey (United States); Francke, Patrick [Carolina Regional Cancer Center, 21st Century Oncology, Myrtle Beach, South Carolina (United States); Mantz, Constantine [21st Century Oncology, Fort Meyers, Florida (United States); Rossi, Peter [Emory University, Atlanta, Georgia (United States); DeWeese, Theodore [The Johns Hopkins University, Baltimore, Maryland (United States); and others

    2015-08-01

    Purpose: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. Methods and Materials: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control). Patients received postprocedure CT and MRI planning scans and underwent image guided intensity modulated radiation therapy (79.2 Gy in 1.8-Gy fractions). Spacer safety and impact on rectal irradiation, toxicity, and quality of life were assessed throughout 15 months. Results: Spacer application was rated as “easy” or “very easy” 98.7% of the time, with a 99% hydrogel placement success rate. Perirectal spaces were 12.6 ± 3.9 mm and 1.6 ± 2.0 mm in the spacer and control groups, respectively. There were no device-related adverse events, rectal perforations, serious bleeding, or infections within either group. Pre-to postspacer plans had a significant reduction in mean rectal V70 (12.4% to 3.3%, P<.0001). Overall acute rectal adverse event rates were similar between groups, with fewer spacer patients experiencing rectal pain (P=.02). A significant reduction in late (3-15 months) rectal toxicity severity in the spacer group was observed (P=.04), with a 2.0% and 7.0% late rectal toxicity incidence in the spacer and control groups, respectively. There was no late rectal toxicity greater than grade 1 in the spacer group. At 15 months 11.6% and 21.4% of spacer and control patients, respectively, experienced 10-point declines in bowel quality of life. MRI scans at 12 months verified spacer absorption. Conclusions: Spacer

  7. DEL DESARROLLO SOSTENIBLE A LA SUSTENTABILIDAD AMBIENTAL

    Directory of Open Access Journals (Sweden)

    JENNIFER LORENA GÓMEZ CONTRERAS

    2014-01-01

    Full Text Available En el presente artículo se presenta una reflexión teórica del concepto de desarrollo, analizando el proceso de eufemización por adjetivo que ha aparecido repetidamente en el discurso desarrollista durante los últimos años, enfatizando en una de sus formas más recientes: el “desarrollo sostenible”. Para este propósito se realizó una investigación cualitativa soportada en una revisión documental. Como resultado de la investigación se evidencia que la expresión “desarrollo sostenible” no deja de ser un oxímoron que termina combinando dos conceptos totalmente opuestos: desarrollo en términos de crecimiento económico y sustentabilidad ecológica, supeditando ésta última al crecimiento. Ante este escenario se propone el concepto de “sustentabilidad ambiental” como una alternativa que escapa del imaginario del desarrollo existente y posibilita el bienestar social y el equilibrio ecológico.

  8. 'Odontologic dosimetric card' experiments and simulations using Monte Carlo methods

    International Nuclear Information System (INIS)

    Menezes, C.J.M.; Lima, R. de A.; Peixoto, J.E.; Vieira, J.W.

    2008-01-01

    The techniques for data processing, combined with the development of fast and more powerful computers, makes the Monte Carlo methods one of the most widely used tools in the radiation transport simulation. For applications in diagnostic radiology, this method generally uses anthropomorphic phantoms to evaluate the absorbed dose to patients during exposure. In this paper, some Monte Carlo techniques were used to simulation of a testing device designed for intra-oral X-ray equipment performance evaluation called Odontologic Dosimetric Card (CDO of 'Cartao Dosimetrico Odontologico' in Portuguese) for different thermoluminescent detectors. This paper used two computational models of exposition RXD/EGS4 and CDO/EGS4. In the first model, the simulation results are compared with experimental data obtained in the similar conditions. The second model, it presents the same characteristics of the testing device studied (CDO). For the irradiations, the X-ray spectra were generated by the IPEM report number 78, spectrum processor. The attenuated spectrum was obtained for IEC 61267 qualities and various additional filters for a Pantak 320 X-ray industrial equipment. The results obtained for the study of the copper filters used in the determination of the kVp were compared with experimental data, validating the model proposed for the characterization of the CDO. The results shower of the CDO will be utilized in quality assurance programs in order to guarantee that the equipment fulfill the requirements of the Norm SVS No. 453/98 MS (Brazil) 'Directives of Radiation Protection in Medical and Dental Radiodiagnostic'. We conclude that the EGS4 is a suitable code Monte Carlo to simulate thermoluminescent dosimeters and experimental procedures employed in the routine of the quality control laboratory in diagnostic radiology. (author)

  9. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd source

    International Nuclear Information System (INIS)

    Sadeghi, Mahdi; Hosseini, Hamed; Raisali, Gholamreza

    2008-01-01

    Full text: The use of 103 Pd seed sources for permanent prostate implantation has become a popular brachytherapy application. As recommended by AAPM the dosimetric characteristics of the new source must be determined using experimental and Monte Carlo simulations, before its use in clinical applications thus The goal of this report is the experimental and theoretical determination of the dosimetric characteristics of this source following the recommendations in the AAPM TG-43U1 protocol. Figure 1 shows the geometry of the IRA- 103 Pd source. The source consists of a cylindrical silver core, 0.3 cm long x 0.05 cm in diameter, onto which 0.5 nm layer of 103 Pd has been uniformly adsorbed. The effective active length of source is 0.3 cm and the silver core encapsulated inside a hollow titanium tube with 0.45 cm long, 0.07 cm and 0.08 inner and outer diameters and two caps. The Monte Carlo N-Particle (MCNP) code, version 4C, was used to determine the relevant dosimetric parameters of the source. The geometry of the Monte Carlo simulation performed in this study consisted of a sphere with 30 cm diameter. Dose distributions around this source were measured in two Perspex phantom using enough TLD chips. For these measurements, slabs of Perspex material were machined to accommodate the source and TLD chips. A value of 0.67± 1% cGy.h -1 .U -1 for, Λ, was calculated as the ratio of d(r 0 ,θ 0 ) and s K , that may be compared with Λ values obtained for 103 Pd sources. Result of calculations and measurements values of dosimetric parameters of the source including radial dose function, g(r), and anisotropy function, F(r,θ), has been shown in separate figures. The radial dose function, g(r), for the IRA- 103 Pd source and other 103 Pd sources is included in Fig. 2. Comparison between measured and Monte Carlo simulated dose function, g(r), and anisotropy function, F(r,θ), of this source demonstrated that they are in good agreement with each other and The value of Λ is

  10. TL dosimetric properties BAM:EU

    International Nuclear Information System (INIS)

    Rao, Bellam N.; Murthy, K.V.R.; Subba Rao, B.; Saiprasad, A.S.

    2011-01-01

    In phosphor area today top priority is the replacement of the high performance but very expensive rare earth activated phosphors with cheaper materials. This essentially means replacing the rare earth ions with transition metal ions or post transition ions. Now a day's phosphors are used in various fields. After World War II, the advances in the optical spectroscopy of solids, especially those of transition metals ions help to evolve research on phosphor and solid state luminescence. In 1960 efficient rare earth activated phosphors were developed for use in color TV (Tb 3+ green, Eu 3+ red, and Dy 3+ yellow). In 1970 tricolor lamp was introduced blue emission from Ce 3+ + Tb 3+ pair was used in tricolor lamps. At present combination of halo phosphor and tri-band phosphor blend is used in many lamp as a compromise between performance, phosphor cost and the lamp making Cost. Thermo luminescence of 0.5 Gy X-ray irradiated BAM.Eu has been studied. The irradiated phosphor has been studied for its TL dosimetric properties one week after irradiation and after 100 weeks of storage. Interesting TL results are reported in the present paper. Heating rate used in the present experiment is 6.6 deg C/Sec. The following two figures are on TL recorded 100 weeks after irradiation and TL recorded after 235 weeks of storage. Before storage for 100 weeks the TL glow curve with a hump around 180 deg C followed by a peak at 273 deg C. After storage for 100 weeks the TL pattern changes entirely. i.e. the composite TL peak structure emerged as two well resolved peaks and with slightly higher TL peak temperatures at 215 deg C and 300 deg C. Normally after storage for 100 weeks the peak at 190 deg C reduces in its intensity or disappears in some cases, instead of that the peak appears at 215 deg C as well resolved peak and its intensity is almost comparable to that of 300 deg C peak. Since the TL phenomenon observed is interesting the two well resolved, isolated, high intensity peaks

  11. TL and LOE dosimetric evaluation of diamond films exposed to beta and ultraviolet radiation

    International Nuclear Information System (INIS)

    Preciado F, S.; Melendrez, R.; Chernov, V.; Barboza F, M.; Schreck, M.; Cruz Z, E.

    2005-01-01

    The diamond possesses a privileged position regarding other materials of great technological importance. Their applications go from the optics, microelectronics, metals industry, medicine and of course as dosemeter, in the registration and detection of ionizing and non ionizing radiation. In this work the results of TL/LOE obtained in two samples of diamond of 10 μm thickness grown by the chemical vapor deposition method (CVD) assisted by microwave plasma. The films were deposited in a silicon substrate (001) starting from a mixture of gases composed of CH 4 /H 2 and 750 ppm of molecular nitrogen as dopant. The samples were exposed to beta radiation (Sr 90 / Y 90 ) and ultraviolet, being stimulated later on thermal (TL) and optically (LOE) to evaluate their dosimetric properties. The sample without doping presented high response TL/LOE to the ultraviolet and beta radiation. The TL glow curve of the sample without doping showed two TL peaks with second order kinetics in the range of 520 to 550 K, besides a peak with first order kinetics of more intensity around 607 K. The TL efficiency of the non doped sample is bigger than the doped with nitrogen; however the LOE efficiency is similar in both samples. The results indicate that the CVD diamond possesses excellent perspectives for dosimetric applications, with special importance in radiotherapy due to it is biologically compatible with the human tissue. (Author)

  12. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  13. An evaluation of the dosimetric performance characteristics of N-vinylpyrrolidone-based polymer gels

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, A E [Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete (Greece); Maris, T G [Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete (Greece); Zacharopoulou, F [Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete (Greece); Pappas, E [Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete (Greece); Zacharakis, G [Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), PO Box 1527, Iraklion, Crete (Greece); Damilakis, J [Department of Medical Physics, Faculty of Medicine, University of Crete, PO Box 2208, Iraklion 71003, Crete (Greece)

    2007-08-21

    The aim of this work was to investigate the dosimetric performance properties of the N-vinylpyrrolidone argon (VIPAR) based polymer gel as a dosimetric tool in clinical radiotherapy. VIPAR gels with a larger concentration of gelatin than the standard recipe were manufactured and irradiated up to 68 Gy using a 6 and 18 MV linear accelerator. Using MRI, the R2-dose response was recorded at different imaging sessions within a 34 day time period post-irradiation. The R2-dose response was found to be linear between 5 and 68 Gy. Although dose sensitivity did not show significant variation with time, the measured R2-dose values showed an increasing trend, which was less evident beyond 17 days. At one day post-irradiation, calculated dose standard uncertainties at 20 Gy and 56 Gy were 2.2% and 1.7%, providing a dose resolution of 0.45 Gy and 0.97 Gy, respectively. Although these values fulfilled the 2% limit of ICRU, when gels were imaged at one day post-irradiation, it was shown that the temporal evolution of the R2 values deteriorated the per cent standard uncertainty and the dose resolution by {approx}57%, when imaged 17 days post-irradiation. Variation in the coagulation temperature of the gels did not impact the R2-dose sensitivity. This study has shown that the VIPAR gel has the properties of a dosimetric tool required in clinical radiotherapy, especially in applications where a wide dose dynamic range is employed. For results with the lowest per cent uncertainty and the optimum dose resolution, the dosimetry gels used in this work should be MR scanned at one day post-irradiation. Furthermore, a preliminary study on the R2-dose response of a new normoxic N-vinylpyrrolidone-based polymer gel showed that it could potentially replace the traditional VIPAR gel formulation, while preserving the wide dynamic dose response inherent to that monomer.

  14. Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology

    International Nuclear Information System (INIS)

    Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T.; Ramirez R, G.; Gaona, E.

    2015-10-01

    Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO 4 : Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO 4 : Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO 4 : Dy). (Author)

  15. DESARROLLO DE COMPETENCIAS INVESTIGATIVAS EN LOS ESTUDIANTES

    Directory of Open Access Journals (Sweden)

    Stalin Fabián Martínez Mora

    2018-03-01

    Full Text Available En el artículo se expone la necesidad del desarrollo de competencias investigativas en los estudiantes para la formación de profesionales comprometidos con el desarrollo social, al favorecer el desarrollo de habilidades, de valores éticos profesionales y cualidades de la personalidad, como la independencia, la responsabilidad, la creatividad y el compromiso con la profesión seleccionada. Se argumenta la relación entre competencias investigativas y conocimiento, debido a que estas permiten a los estudiantes apropiarse de conocimientos y analizar de una forma más crítica y lógica el entorno que les rodea, lo cual les permitirá enfrentarse a la solución de problemas relevantes.

  16. Desarrollo de videojuegos sobre la plataforma android

    OpenAIRE

    García Povedano, David

    2012-01-01

    Este PFC está enfocado a la elaboración de tres videojuegos para dispositivos móviles con sistema operativo Android. Para ello se ha estudiado la arquitectura del sistema operativo Android, así como las herramientas necesarias para el desarrollo de aplicaciones para Android. Tras esto, se ha pasado a investigar y aprender el funcionamiento de una librería Open Source para el desarrollo de videojuegos (AndEngine). Y como conclusión y aplicación de lo aprendido, se han desarrollado tres videoju...

  17. CONTABILIDAD MACROECONÓMICA Y DESARROLLO REGIONAL

    OpenAIRE

    Cárdenas Núñez, Gilberto José Rafael

    2014-01-01

    Las cuentas de producción departamental actualizadas son indispensables para los planes de desarrollo que orienten el crecimiento de la economía nacional y el desarrollo integral del país. Esta información tiene que elaborarse en forma departamental. Las enormes diferencias productivas y de bienestar entre los departamentos del país obligan al sector público y al privado a trabajar en forma conjunta para realizar las inversiones necesarias en base al capital humano y los recursos naturales di...

  18. Turismo, educación y desarrollo

    OpenAIRE

    Mantero, Juan Carlos

    2004-01-01

    El presente documento aspira a presentar una serie de reflexiones a propósito de las relaciones entre turismo, educación y desarrollo, relaciones de recíproca exigencia al plantearse la exigencia de su necesaria contribución a un más saber para un mejor vivir. Las reflexiones se vertebran mediante el desarrollo de una sucesión de temas generados a través del ejercido de la investigación, la docencia y la transferencia realizadas en el contexto de nuestra actividad universitaria realizada en e...

  19. Desarrollo social y personalidad. Una perspectiva interdisciplinar

    OpenAIRE

    Riesco González, Manuel

    2012-01-01

    En las siguientes páginas se pretende establecer un diálogo interdisciplinar y abierto sobre cuestiones relevantes acerca del desarrollo social y de la personalidad. A partir de una breve reseña histórica del tema desde una perspectiva psicológica, se trata de comprender, con una visión amplia, el progreso humano como marco general del desarrollo social y de las personas. Finalmente, se muestra un bosquejo de la sociedad actual, definida como “sociedad del conocimiento”, “sociedad abierta” y ...

  20. Dose reader of dosimetric foil; Czytnik dawki folii dozymetrycznej

    Energy Technology Data Exchange (ETDEWEB)

    Machaj, B.; Strzalkowski, J.; Smolko, K.

    1997-12-31

    Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement caused by the instabilities does not exceed 0.0004 A. (author). 3 refs, 3 figs.

  1. EchoSeed Model 6733 Iodine-125 brachytherapy source: Improved dosimetric characterization using the MCNP5 Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Mosleh-Shirazi, M. A.; Hadad, K.; Faghihi, R.; Baradaran-Ghahfarokhi, M.; Naghshnezhad, Z.; Meigooni, A. S. [Center for Research in Medical Physics and Biomedical Engineering and Physics Unit, Radiotherapy Department, Shiraz University of Medical Sciences, Shiraz 71936-13311 (Iran, Islamic Republic of); Radiation Research Center and Medical Radiation Department, School of Engineering, Shiraz University, Shiraz 71936-13311 (Iran, Islamic Republic of); Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States)

    2012-08-15

    This study primarily aimed to obtain the dosimetric characteristics of the Model 6733 {sup 125}I seed (EchoSeed) with improved precision and accuracy using a more up-to-date Monte-Carlo code and data (MCNP5) compared to previously published results, including an uncertainty analysis. Its secondary aim was to compare the results obtained using the MCNP5, MCNP4c2, and PTRAN codes for simulation of this low-energy photon-emitting source. The EchoSeed geometry and chemical compositions together with a published {sup 125}I spectrum were used to perform dosimetric characterization of this source as per the updated AAPM TG-43 protocol. These simulations were performed in liquid water material in order to obtain the clinically applicable dosimetric parameters for this source model. Dose rate constants in liquid water, derived from MCNP4c2 and MCNP5 simulations, were found to be 0.993 cGyh{sup -1} U{sup -1} ({+-}1.73%) and 0.965 cGyh{sup -1} U{sup -1} ({+-}1.68%), respectively. Overall, the MCNP5 derived radial dose and 2D anisotropy functions results were generally closer to the measured data (within {+-}4%) than MCNP4c and the published data for PTRAN code (Version 7.43), while the opposite was seen for dose rate constant. The generally improved MCNP5 Monte Carlo simulation may be attributed to a more recent and accurate cross-section library. However, some of the data points in the results obtained from the above-mentioned Monte Carlo codes showed no statistically significant differences. Derived dosimetric characteristics in liquid water are provided for clinical applications of this source model.

  2. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

    International Nuclear Information System (INIS)

    Vargas, J.; Vivanco, M.; Castro, E.

    2014-08-01

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  3. Personal dosimetric monitoring in Ukraine: current status and further development

    International Nuclear Information System (INIS)

    Chumak, V. V.; Musijachenkom, A. V.; Boguslavskaya, A. I.

    2003-01-01

    Presently Ukraine has mixed system for dosimetric monitoring. Nuclear power plants and some major nuclear facilities have their own dosimetry services, which are responsible for regular dosimetric monitoring of workers. Rest of occupationally exposed persons is monitored by dosimetry laboratories affiliated to the territorial authorities for sanitary and epidemiology supervision. In 2002-2003 Ukrainian Ministry of Health performed survey of the status of dosimetric monitoring and inventory of critical groups requiring such monitoring. Dosimetry services in Ukraine cover about 38,000 occupationally exposed workers, including 9,100 medical professionals, 16,400 employees of 5 nuclear power plants and ca.12,400 workers dealing with other sources of occupational exposure (industry, research). Territorial dosimetry services operate in 13 of 24 regions of Ukraine, using DTU-01 manual TLD readers produced with one exception in 1988-1990. The coverage of critical groups by dosimetric monitoring is variable and ranges from 38% to 100% depending on the region. Personnel of nuclear power plants (about 16,400 workers) is monitored by their own dosimetry services achieving absolute coverage of the main staff and temporary workers. Current inadequate status of dosimetric monitoring infrastructure in Ukraine demands an urgent elaboration of the united state system for monitoring and recording of individual doses. The proposed plan would allows to bring dosimetry infrastructure in Ukraine to the modern state which would be compatible with existing and future European and international radiation protection networks. Unitary structure of Ukraine, strong administrative command and good communications between regions of the country are positive factors in favour of efficient implementation of the proposed plan. Deficiencies are associated with limited funding of this effort. (authors)

  4. The Need for New Dosimetric Approach in CT Dosimetry

    International Nuclear Information System (INIS)

    Ben-Shlomo, A.; Iacobovici, E.

    2004-01-01

    Three decades after the invention of the first CT in 1972, it became a major tool in diagnostic radiology. The use of CT for various applications is getting wider every year. The quantity of CT procedures performed in Israel every year is estimated as 500,000. About 10% of those are pediatric procedures, for children under age 10. CT procedures increase is estimated at 5-10 % per annum. In spite the fact that CT contributes to about 1/8 of the total number of diagnostic X-ray procedures in Israel, the CT collective dosage is about 40% of the total collective dosage in the said procedures (about 3,500 Man*Sv per year). Medical radiation dosage is the first contributor to population dosage, resulting from artificial radiation sources. Diagnostic X-ray radiation dosage is the first contributor to medical radiation dose (including radiation dose from diagnostic X-ray, nuclear medicine and radiotherapy with exclusion of the target organ dose). Among medical X-ray different applications, CT procedure is the first cause to radiation dose of the population according to X-ray diagnostic procedures. The above facts emphasize the need to focus on CT in order to reduce the medical collective dose of the public. Several dosimetric units have appeared in recent years in order to comply with the need for CT Dosimetry. The CTDI Unit that served so well during the first CT years is no longer sufficient, as is, for modern instruments. This basic unit has become a complex concept that covers new units: CTDI W , CTDI VOL , CTDI 100 , MSAD and DLP. The search for a simple way to apply these units in order to calculate effective dosage during CT examinations is not straightforward. Modern equipment is simultaneously using 4 and 16 slices. Manufacturers are endeavoring to develop the next generation equipment with 256 slices used simultaneously (expected on the market in the next 1-2 years). This situation sets technology one step forward regarding the dosimetry methods used for organ

  5. Petróleo, desarrollo y paz

    OpenAIRE

    Martínez O., Astrid

    2009-01-01

    Este articulo analiza los planteamientos del Gobierno Nacional sobre politica petrolera. La relacion entre el petroleo y los temas de desarrollo y la paz se exploran con base en la lectura de los pronunciamientos de la guerrilla y los grupos sociales sobre el manejo de los hidrocarburos en Colombia vis a vis los pronunciamientos gubernamentales.

  6. Dosimetric characterization of chemical-vapor-deposited diamond film irradiated with UV and beta radiation

    Science.gov (United States)

    Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; Barboza-Flores, M.

    2003-03-01

    Diamond is an excellent prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality polycrystalline has renewed the interest in using diamond films as detectors and dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by using chemical vapor deposition. The thermoluminescence (TL) of UV and beta exposed samples shows a glow curve composed of at least four peaks; one located around 587 K presents excellent TL properties suitable for dosimetric applications with ionizing and non ionizing radiation. The TL excitation spectrum exhibits maximum TL efficiency at 220 nm. The samples show regions of linear as well as supralinear behavior as a function or irradiation dose. The linear dose dependence was found for up to sixteen minutes of UV irradiation and 300 Gy for beta irradiated samples. The activation energy and the frequency factor were determined and found in the range of 0.32 - 0.89 eV and 1.1x10^2 - 2x10^8s_-1, respectively. The observed TL performance is reasonable appropriate to justify further investigation of diamond films as radiation dosimeters.

  7. ESR Spectra of Some Silicate Minerals: A Search For New Dosimetric Materials

    International Nuclear Information System (INIS)

    Abdel-Monem, A.A.; Abdel-Razek, Y.A.; Rasheed, G. M.; Hassan, G.M.; Eissa, H.M.; Morsy, M.

    2008-01-01

    Two silicate minerals talc (Mg 3 Si 4 O 1 0 (OH) 2 ) and zircon (ZrSiO 4 ) having different crystal lattice structures were subjected to ESR dosimetric studies. Zircon shows anisotropic ESR signals at g xx =2.0168, g yy =2.0076 and g zz =2.0033, which have been identified as a hole center associated with Y 3+ substituted at Zr 4+ sites. Other characteristic signals have been observed and identified. The ESR signal at g=2.0033 showed positive response to γ-irradiation at 110 Gy and is suitable to be used for dosimetry and dating of natural zircons. Talc a magnesium sheeted silicate exhibits ESR derivative spectrum characterized the presence of Fe 3+ at g=4.28 and the HF-sixtet Mn 2+ signals due to possible substitution of Fe 3+ and Mn 2+ in the Mg 2+ octahedral sites, respectively. The enhancement of the Mn 2+ sixtet by γ-irradiation increases the area occupied by the signals which makes it difficult to use for dosimetric applications

  8. New routes of preparation of polyaniline films and dosimetric characterization for high-doses gamma radiation

    International Nuclear Information System (INIS)

    Pacheco, Ana Paula Lima

    2003-08-01

    This work presents a new conducting polymeric material based on polyaniline thin films that will be used in the confection of dosimetric devices. On preparation of the films a homogeneous and viscous solution of poly (acrylic acid) and MnO 2 is deposited on PMMA surface, which after dried, is immersed in an acid aniline solution. The films formed present low resistivity (6.10 2 Ωm), good mechanical resistance and adherence on the electrodes. The films were characterized by infrared spectroscopy, conductivity measurements and manganese elemental analyses. The resistance variations show linear correlation (r 2 = 0,9928) with gamma irradiation dose in the range of 1000 to 6000 Gy, with medium error less than 5% and sensitivity response. The dosimetric devices present as advantage real time measurements, low cost, use in calibration of industrial radioactive sources. Moreover, this composite could in future replace Fricke dosimeter and its applications. A calibration curve is showed for PANI dosimeter, here proposed, to use at high gamma doses. (author)

  9. Recovery of α-Al{sub 2}O{sub 3} from ionizing radiation dosimetric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, Edgar Aparecido, E-mail: sanches.ufam@gmail.com [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Dept. de Fisica; Costalonga, Ademir Geraldo Cavallari; Mascarenhas, Yvonne Primerano [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Institute de Fisica; Nascimento, Luana de Freitas [Belgium Nuclear Research Centre, SCK-CEN, Mol (Belgium); Mascarenhas, Yvone Maria [SAPRA S/A Servico de Assessoria e Protecao Radiologica, Sao Carlos, SP, (Brazil)

    2015-01-15

    Corundum, sapphire or α-Al{sub 2}O{sub 3} is an important technological material in many optical and electronic applications such as solid-state lasers, optical windows and, more recently, as a radiation detector. Landauer (Glenwood, IL, USA) accumulated large number of archived and stored Luxel™ dosemeters composed of Al{sub 2}O{sub 3}:C, which were subjected to a recovery process. Due to the importance of this advanced crystalline material in OSL dosimetry, a recovery process was developed based on the dosemeters calcination and Al{sub 2}O{sub 3}:C has been reused in manufacturing of new dosemeters. This paper does not aim to optimize the recovery process, but provides an opportunity to study the involved process parameters and to recover this valuable crystalline material from used dosemeters. To the best of our knowledge no other recovery process involving this dosimetric material was described in scientific literature. Fourier Transform Infrared Spectrometry (FTIR), Thermogravimetry/Differential Thermoanalysis (TG/DTA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Optically Stimulated Luminescence (OSL) and Rietveld Refinement were used to characterize the recovered material and to check for the stability of its structural and dosimetric properties. (author)

  10. Synthesis of xerogels with Europium impurities for dosimetric applications

    International Nuclear Information System (INIS)

    Rivera R, C.; Garcia R, F.J.; Yanez L, M. -

    2007-01-01

    The objective of this work is the obtaining xerogels in bundle of SiO 2 with europium impurities to low concentrations, with the objective of exploring their mechanical, optical and emission properties. The obtained xerogels was synthesized by means of the sol-gel technique, using water, TEOS and ethanol to a molar relationship 16:1:4 respectively, the europium was added by oxide via to the precursor solution and to catalyze the hydrolysis condensation reaction, its were added: nitric acid and hydrofluorhydric acid. Later on these mixtures were left to gel by 72 hours and under this same composition, but with different quantities of impurifying material (0.0, 0.01 and 0.05g of europium oxide), the materials were dried in a ramp of controlled temperature, from ambient temperature up to 120 C, some of these thermally tried materials were calcined at 500 and 800 C, being obtained in this way xerogels free of fractures, stable, porous and semi-transparent. The characterization of these materials includes: pH measurements and solutions viscosity during the gelation stage, as well as characterization of their optic properties by means of infrared spectroscopy, UV-vis and emission spectroscopy. The microhardness results show that these materials present smaller values to those corresponding of the corning glass, as well as a growing behavior with regard to the calcination temperatures of the material. (Author)

  11. Dosimetric properties of a radiochromic gel detector for diagnostic X-rays

    International Nuclear Information System (INIS)

    Bero, M.A.

    2007-01-01

    The gel dosimetry method was found to be capable of addressing complicated issues related to dose measurements particularly in modern sophisticated radiotherapy applications. The Ferrous-sulphate Xylenol-orange and Gelatin (FXG) radiochromic gel dosemeter is one of the systems used for such applications. Some chemical dosemeters show different responses for low- and medium-energy X-rays in comparison with high-energy γ-photons. The energy and dose rate dependence of the FXG dose response was examined. In addition to the detector response, other important dosimetric properties of the system were investigated for different X-ray beam qualities with tube voltages in the range 100-300 kV. An orthovoltage X-ray therapy unit was used to irradiate standard sized samples of FXG from different batches for radiation doses in the range 0-20 Gy

  12. Comparison of dosimetric methods for virtual wedge analysis

    International Nuclear Information System (INIS)

    Bailey, M.; Nelson, V.; Collins, O.; West, M.; Holloway, L.; Rajapaske, S.; Arts, J.; Varas, J.; Cho, G.; Hill, R.

    2004-01-01

    Full text: The Siemens Virtual Wedge (Concord, USA) creates wedged beam profile by moving a single collimator jaw across the specified field size whilst varying the dose rate and jaw speed for use in the delivery of radiotherapy treatments. The measurement of the dosimetric characteristics of the Siemens Virtual Wedge poses significant challenges to medical physicists. This study investigates several different methods for measuring and analysing the virtual wedge for data collection for treatment planning systems and ongoing quality assurance. The beam profiles of the Virtual Wedge (VW) were compared using several different dosimetric methods. Open field profiles were measured with Kodak X-Omat V (Rochester, NY, USA) radiographic film and compared with measurements made using the Sun Nuclear Profiler with a Motorized Drive Assembly (MDA) (Melbourne, FL, USA) and the Scanditronix Wellhofer CC13 ionisation chamber and 24 ion Chamber Array (CA24) (Schwarzenbruck, Germany). The resolution of each dosimetric method for open field profiles was determined. The Virtual Wedge profiles were measured with radiographic film the Profiler and the Scanditronix Wellhofer CA 24 ion Chamber Array at 5 different depths. The ease of setup, time taken, analysis and accuracy of measurement were all evaluated to determine the method that would be both appropriate and practical for routine quality assurance of the Virtual Wedge. The open field profiles agreed within ±2% or 2mm for all dosimetric methods. The accuracy of the Profiler and CA24 are limited to half of the step size selected for each of these detectors. For the VW measurements a step size of 2mm was selected for the Profiler and the CA24. The VW profiles for all dosimetric methods agreed within ±2% or 2mm for the main wedged section of the profile. The toe and heel ends of the wedges showed the significant discrepancies dependent upon the dosimetry method used, up to 7% for the toe end with the CA24. The dosimetry of the

  13. Comunicación para un desarrollo diferente

    OpenAIRE

    Adalid Contreras

    2015-01-01

    Analizar las relaciones entre comunicación y desarrollo supone combinar tres puntos de partida: la realidad presente, el futuro posible y la memoria acumulada. El desarrollo está en deuda con la sociedad; la comunicación está en deuda con el desarrollo; y la teoría está en deuda con la experiencia para lograr un cambio de la exclusión y la, pobreza. Hace una diferenciación entre lo que es comunicación de desarrollo; comunicación de apoyo al desarrollo; Comunicación alternativa para el desarro...

  14. Computational model for dosimetric purposes in dental procedures

    International Nuclear Information System (INIS)

    Kawamoto, Renato H.; Campos, Tarcisio R.

    2013-01-01

    This study aims to develop a computational model for dosimetric purposes the oral region, based on computational tools SISCODES and MCNP-5, to predict deterministic effects and minimize stochastic effects caused by ionizing radiation by radiodiagnosis. Based on a set of digital information provided by computed tomography, three-dimensional voxel model was created, and its tissues represented. The model was exported to the MCNP code. In association with SICODES, we used the Monte Carlo N-Particle Transport Code (MCNP-5) method to play the corresponding interaction of nuclear particles with human tissues statistical process. The study will serve as a source of data for dosimetric studies in the oral region, providing deterministic effect and minimize the stochastic effect of ionizing radiation

  15. Dosimetric considerations and radiation protection of patients in interventional cardiology

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, O.; Arandjic, D.; Kosutic, D.; Loncar, B.

    2009-01-01

    The paper summarizes results of measurements of relevant dosimetric quantities in interventional cardiology. Dosimetric data were collected for 117 coronary angiography (CA) procedures, 69 percutaneous coronary interventions (PCI) and 41 combined procedures (CA+PCI), taking into account two quantities: air kerma area product (KAP) d air kerma in international reference point (K IRP ). Mean KAP values were 78 Gy·cm 2 , 113 Gy·cm 2 and 141 Gy·cm 2 for CA, PCI i CA+PCI, respectively. Corresponding mean K IRP values were 1.2 Gy, 1.8 Gy and 2.2 Gy. With respect to high dose values, risk for stochastic effects and tissue reactions, dose management methods were proposed. (author) [sr

  16. Influence of lucite phantoms on calibration of dosimetric pens

    International Nuclear Information System (INIS)

    Oliveira, E.C.; Xavier, M.; Caldas, L.E.V.

    1992-01-01

    Dosimetrical pens were studied for the answer repetition and were tested in gamma radiation fields ( 60 Co and 137 Cs) in air and in front of a lucite phantom, obtaining a backscattering contribution. The medium backscattering factors were 1,053 and 1,108 for respectively 60 Co and 137 Cs. The pens were placed behind the phantom for verifying the radiation attenuation. (C.G.C.)

  17. Dosimetric improvements following 3D planning of tangential breast irradiation

    International Nuclear Information System (INIS)

    Aref, Amr; Thornton, Dale; Youssef, Emad; He, Tony; Tekyi-Mensah, Samuel; Denton, Lori; Ezzell, Gary

    2000-01-01

    Purpose: To evaluate the dosimetric difference between a simple radiation therapy plan utilizing a single contour and a more complex three-dimensional (3D) plan utilizing multiple contours, lung inhomogeneity correction, and dose-based compensators. Methods and Materials: This is a study of the radiation therapy (RT) plans of 85 patients with early breast cancer. All patients were considered for breast-conserving management and treated by conventional tangential fields technique. Two plans were generated for each patient. The first RT plan was based on a single contour taken at the central axis and utilized two wedges. The second RT plan was generated by using the 3D planning system to design dose-based compensators after lung inhomogeneity correction had been made. The endpoints of the study were the comparison between the volumes receiving greater than 105% and greater than 110% of the reference dose, as well as the magnitude of the treated volume maximum dose. Dosimetric improvement was defined to be of significant value if the volume receiving > 105% of one plan was reduced by at least 50% with the absolute difference between the volumes being 5% or greater. The dosimetric improvements in 49 3D plans (58%) were considered of significant value. Patients' field separation and breast size did not predict the magnitude of improvement in dosimetry. Conclusion: Dose-based compensator plans significantly reduced the volumes receiving > 105%, >110%, and volume maximum dose.

  18. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  19. Gamma dosimetric parameters in some skeletal muscle relaxants

    Science.gov (United States)

    Manjunatha, H. C.

    2017-09-01

    We have studied the attenuation of gamma radiation of energy ranging from 84 keV to 1330 keV (^{170}Tm, ^{22}Na,^{137}Cs, and ^{60}Co) in some commonly used skeletal muscle relaxants such as tubocurarine chloride, gallamine triethiodide, pancuronium bromide, suxamethonium bromide and mephenesin. The mass attenuation coefficient is measured from the attenuation experiment. In the present work, we have also proposed the direct relation between mass attenuation coefficient (μ /ρ ) and mass energy absorption coefficient (μ _{en}/ρ ) based on the nonlinear fitting procedure. The gamma dosimetric parameters such as mass energy absorption coefficient (μ _{en}/ρ ), effective atomic number (Z_{eff}), effective electron density (N_{el}), specific γ-ray constant, air kerma strength and dose rate are evaluated from the measured mass attentuation coefficient. These measured gamma dosimetric parameters are compared with the theoretical values. The measured values agree with the theoretical values. The studied gamma dosimetric values for the relaxants are useful in medical physics and radiation medicine.

  20. Ciencia, tecnología y desarrollo

    Directory of Open Access Journals (Sweden)

    Tomás V. Unger

    2015-01-01

    Full Text Available En América Latina el escribir sobre ciencia comparte una responsabilidad: el desarrollo tecnológico que piden todos los países del Tercer Mundo. Es función del periodismo científico crear interés en la ciencia, propugnar su difusión y apuntalar su enseñanza,función que está íntimamente ligada al desarrollo, pues sin ciencia y tecnología no es posible alcanzarlo. La ciencia consiste en llegar al por qué de las cosas y deducir reglas generales con las cuales se pueda predecir fenómenos que aún no han ocurrido. Esto a su vez permite crear procesos, primero de laboratorio, luego industriales, que devienen en tecnologías de producción,

  1. SCODA para el Desarrollo de Sistemas Multiagente

    Directory of Open Access Journals (Sweden)

    Jesús A. Román

    2011-12-01

    Full Text Available El planteamiento de implementar sistemas multiagente de forma que puedan reutilizarse con distintos objetivos, dota a los desarrolladores de una metodología más eficaz en sus fines. Este artículo presenta SCODA, una arquitectura basada en cinco principios: estandaridad, especialización, facilidad de implementación, reutilización y computación distribuida. SCODA pretende facilitar el desarrollo de sistemas multiagente, basándose en el concepto de pequeños grupos de agentes denominados Comunidades Inteligentes Especializadas (CIE. Las CIE cuentan con funcionalidades específicas que permiten llevar a cabo la implementación de sistemas multiagente de forma escalable, dentro del marco de SCODA, pudiendo ser reutilizadas en diversos desarrollos.

  2. Pensamiento y lenguaje, productos del desarrollo social

    Directory of Open Access Journals (Sweden)

    Jesús Rodríguez-Cotorruelo

    2017-11-01

    Full Text Available En el artículo se hace una valoración sobre la relación dialéctica entre el pensamiento y el lenguaje desde una posición materialista, señalando que el pensamiento es el reflejo del mundo objetivo en la mente del hombre siendo material por su contenido, pero subjetivo por su forma, solo existe en forma de idea y puede transmitirse mediante su envoltura material, el lenguaje. El pensamiento y el lenguaje son productos del desarrollo social y existirán siempre que existan seres humanos. El desarrollo científico tecnológico dará origen a nuevas formas de transmitir el pensamiento, pero siempre será mediante el lenguaje desarrollado por el hombre.

  3. El desarrollo organizacional como facilitador del cambio

    Directory of Open Access Journals (Sweden)

    Henry Molina

    2000-01-01

    Full Text Available El Desarrollo Organizacional (DO ha surgido de las exigencias de un ambiente cambiante y del conocimiento originado por la evolución de las ciencias sociales aplicadas. Los cambios rápidos dentro del entorno organizacional han exigido procesos y estructuras organizacionales que sean mucho más flexibles y que brinden mayor capacidad de respuesta que las estructuras tradicionales. Se requieren nuevas capacidades individuales y organizacionales que puedan impulsar las iniciativas individuales y la disposición para asumir riesgos. Igualmente, debemos considerar que existen marcadas diferencias entre las características individuales de los gerentes, las características individuales de los profesionales del desarrollo organizacional, sus habilidades y conocimientos y los estilos de las intervenciones del desarrollo organizacional. Tbdas estas diferencias hacen que sea virtualmente imposible predecir con precisión el curso y los resultados de las intervenciones en las organizaciones cliente. En este documento presento un resumen de lecturas acerca del desarrollo organizacional como facilitador del cambio; y expongo un marco de referencia para la comprensión de los factores determinantes de la relación entre las intervenciones del DO y los cambios organizacionales con el fin de mejorar la predictabilidad y la efectividad de los esfuerzos de cambio de sus intervenciones. El propósito central de este documento es dotar a los agentes de cambio de conocimiento y herramientas para que comprendan las características del cambio, los métodos de aprendizaje tanto de las organizaciones como de la gente y de cómo los agentes de cambio deben diseñar sus intervenciones y posteriormente mejorar los resultados de las mismas

  4. Use of a dosimetric system using a SMT phototransistor in the measurement for some dosimetric parameters in conventional radiotherapy

    International Nuclear Information System (INIS)

    Silva, J.O. da; Magalhaes, C.M.S. de; Santos, L.A.P.

    2008-01-01

    For monitoring the delivered dose in the patient undergoing a cancer treatment with high-energy ionizing radiation beams is necessary to use appropriate dosimeters for the beam control quality and if it is possible, to obtain the dose information during the treatment. For this, semiconductor-based devices are used because of their high spatial resolution and to be easy to handle in spite of the ionization chambers. Nowadays the bipolar phototransistors are being proposed as ionizing radiation detectors for presenting, beyond these characteristics, the signal amplification factor (gain). So, the aim of this work is to present the use of a dosimetric system using a SMT phototransistor in the measurement for some dosimetric parameters in conventional radiotherapy: the field factor and the off-axis ratio. The phototransistors readings were compared with ones obtained from a PTW 23343 Markus chamber, under the same conditions. (author)

  5. Género, Desarrollo y Cooperación al Desarrollo

    Directory of Open Access Journals (Sweden)

    Teresa Rendón

    2003-02-01

    Full Text Available La diferenciación social existente entre hombres y mujeres -denominada "género"en la literatura de nuestros días- es considerada como una de las modalidades de desigualdad más generalizadas en el mundo contemporáneo. Por lo tanto, lograr la igualdad social entre los sexos constituye uno de los objetivos del desarrollo y de la cooperación al desarrollo. En un principio, a la luz de un enfoque denominado "Mujeres en el desarrollo", se buscaba una mayor y mejor integración femenina a la actividad económica para el mercado, mediante programas productivos y de capacitación dirigidos a grupos de mujeres. Más tarde, este enfoque centrado en las mujeres, se sustituyó por el de "Género en el Desarrollo", un enfoque más amplio e integrado que abarca los distintos ámbitos del desarrollo y de la cooperación, pues se reconoce que el problema de la inequidad entre los sexos no atañe sólo a las mujeres sino a la sociedad en su conjunto. No obstante, entre los planes y programas y su puesta en práctica hay todavía una enorme brecha.

  6. Biocomercio: una alternativa para el desarrollo sostenible

    Directory of Open Access Journals (Sweden)

    Carlos Murillo R.

    2008-01-01

    Full Text Available El desarrollo sostenible en países ricos en biodiversidad dependerá de la capacidad de los gobiernos de implementar los arreglos institucionales necesarios para conciliar la preservación de los recursos naturales con el uso de los mismos para la producción de bienes y servicios que puedan potenciar el crecimiento económico y un mayor bienestar para las comunidades locales donde estos recursos se encuentren. Este es el objetivo de la Iniciativa de Biocomercio que ha venido impulsando la Conferencia de Naciones Unidas para el Comercio y el Desarrollo (UNCTAD en distintos países de Latinoamérica. En el tanto estos principios y los establecidos en el CDB se puedan viabilizar e inspiren los distintos Programas Nacionales de Biocomercio en los países de la región, parecería no haber dudas de que la Iniciativa abre nuevas puertas para el uso, aprovechamiento y desarrollo sostenible de los mismos.

  7. OBJETIVO DEL DESARROLLO DEL MILENIO 7

    Directory of Open Access Journals (Sweden)

    Margarita M. Pérez O.

    2013-10-01

    Full Text Available Los Objetivos de Desarrollo del Milenio, también conocidos como los Objetivos del Milenio, constituyeron las metas finales que aprobaron los dirigentes mundiales, 189 jefes de estado y de gobierno en la Cumbre del Milenio de las Naciones Unidas celebrada en Nueva York en el año 2000, en la cual los Estados miembros de la organización reafirmaron su compromiso de luchar por un mundo en el que el desarrollo sostenible y la eliminación de la pobreza tuvieran máxima prioridad1 . En la cumbre se definió la Declaración del Milenio, la cual detalla los objetivos, principios, valores, metas y acciones para erradicar la pobreza Mundial hacia el año 2015, todos ellos ratificados con alto interés y acción estratégica de carácter global, como marco para la medición de los progresos en materia de desarrollo.

  8. Desarrollo sustentable: fundamentos, perspectivas y limitaciones

    Directory of Open Access Journals (Sweden)

    Badii, M. H.

    2004-07-01

    Full Text Available Se explican la filosofía, las nociones y los conceptos fundamentales del desarrollo sustentable, y enfatizan los desastres socioeconómicos, políticos e ecológicos que amenazan seriamente a la humanidad entera. Contrastan las diferencias abismales entre los países desarrollados y los país pobres y en vía de desarrollo. Se mencionan los intentos fallidos del ser humano conciente desde 1972 (la Declaración de Estocolmo al tratar de buscar salidas a los problemas ambientales y enfatizan los intereses de los conglomerados superpoderosos como obstáculos al progreso del desarrollo sustentable. Se mencionan los indicadores de sustentabilidad y también los índices con énfasis sobre la estimación de los factores de educación, salud, pobreza, medioambiente e ecología. Se define el concepto de la biodiversidad y los modelos matemáticos de uso actual para su estimación.

  9. Propiedad intelectual y desarrollo en Colombia

    Directory of Open Access Journals (Sweden)

    Karl W. Mutter

    2010-03-01

    Full Text Available Un país sin conocimiento propio está condenado a de­ pender de otros en casi todos los aspectos, y actualmente los países poseedores del conocimiento son, por obvias razones, los baluartes de su protección. Aunque los sistemas de protección de este conocimiento -propiedad intelectual (PI-han sido muy criticados, podrían también ser aprovechados para desarrollar conocimiento propio, lo cual es fundamental para el progreso y avance de los países en desarrollo, en particular Colombia. Este artículo analiza la relación entre propiedad intelectual y desarrollo, y las discusiones que sobre esta relación se están llevando a cabo en el ámbito de organizaciones multilaterales como la OMPI y la OMC; analiza también las experiencias de otros países que han basado de manera exitosa su desarrollo en la creación de conocimiento, como es el caso de Corea del Sur. Igualmente, se estudia el contexto colombiano y los esfuerzos que podrían llevarse a cabo en áreas como iniciativas normativas en transferencia efectiva de tecnología, y la promoción e impuso de áreas económicas no tradicionales en temas como software, biotecnología, industrias creativas, indicaciones geográficas, entre otras.

  10. The role of the Secondary Laboratory of Dosimetric calibration in the implementation of the dosimetric magnitudes with radiological protection aims

    International Nuclear Information System (INIS)

    Perez Medina O, V.; Alvarez R, J.T.; Tovar M, V.M.

    2006-01-01

    It is very well-known the paper of the net of secondary laboratories of dosimetric calibration of the OAS in the dissemination of the traceability of the dosimetric magnitudes: kerma in air and absorbed dose in water, to the radiotherapy departments, given the high accuracy and precision that require the radiotherapy treatments. However the LSCD has other important areas at least for the development, implementation and evaluation of dosimetric magnitudes denominated operative magnitudes with ends of radiological protection: environmental equivalent dose H*(10), directional equivalent dose H'(0.07) and personal equivalent dose Hp. In the case of radiological protection the LSCD-ININ has been implementing the infrastructure to give service of personal dosimetry for photons and beta particles in terms of the operative magnitudes. For photons: X and gamma rays, it account with a secondary pattern camera PTW T34035 gauged in H * and Hp in the primary laboratory of Germany PTB. For the case of beta radiation its account with an extrapolation camera PTW 23392 with a secondary pattern kit of sources of the type I, gauged in terms of H'(0.07) in the PTB. (Author)

  11. Thermoluminescent dosimetric characterization of the perovskite, KMgF3, activated with lanthanum

    International Nuclear Information System (INIS)

    Sepulveda M, F.

    2003-01-01

    The new ICRP regulation about the Radiological Protection allows to the different groups to study new thermoluminescent materials highly sensitive for dosimetric applications (personal and environmental). This work reports the relative experimental results to the thermoluminescent characteristic of a new preparation of the fluorine perovskite activated with lanthanum absorbed in polytetrafluoroethylene (KMgF 3 : LaF 3 + Ptfe). The main thermoluminescent properties investigated were: the TL response like a function of the absorbed dose, the attainable accuracy in the dose measurement, the reproducibility of the TL readings and the threshold dose. The obtained results were compared with the requirements of the ANSI protocol for the environmental dosimetry, resulting in a very good agreement with the required yields. (Author)

  12. Dosimetric comparison of treatment techniques IMRT and VMAT for breast cancer

    International Nuclear Information System (INIS)

    Urbina, G. L.; Garcia, B. G.

    2015-10-01

    In this study the dosimetric distribution was compared in the different treatment techniques such as Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) in female patients with breast cancer with stage II-B and III-A, 6 cases (both calculated on VMAT and IMRT) were studied, comparison parameter that are taken into account are: compliance rate, homogeneity index, monitor units, volume dose 50 Gy (D-50%) and 5 Gy (D-5%) volume dose. Comparisons are made in primary tumor volume to optimize treatment in patients with breast cancer, with IMRT using Step, Shoot and VMAT Monte Carlo algorithm, in addition to the organs at risk; the concern to make this work is due to technological advances in radiotherapy and the application of new treatment techniques, that increase the accuracy allowing treatment dose climbing delivering a higher dose to the patient. (Author)

  13. Comunicación para un desarrollo diferente.

    OpenAIRE

    Contreras Baspineiro, Adalid

    1999-01-01

    Analizar las relaciones entre comunicación y desarrollo supone combinar tres puntos de partida: la realidad presente, el futuro posible y la memoria acumulada. El desarrollo está en deuda con la sociedad; la comunicación está en deuda con el desarrollo; y la teoría está en deuda con la experiencia para lograr un cambio de la exclusión y la pobreza

  14. Qualitative dosimetric system for radiation processing. Technology for pilot scale preparation

    International Nuclear Information System (INIS)

    Moraru, R.

    1998-01-01

    Good manufacturing practice for radiation processing requires a very strictly tracking of the processed products. A method of labelling and identification of the irradiated and nonirradiated products is required. The qualitative dosimetric system provides a fast method for monitoring the product flow. Such dosimeters are attached on each product box, usually as labels, and offer a YES/NO information about the passing of products through the radiation field. Usually, this information consists in a change of colour. The qualitative dosimetric system that we realised is based on the degradation of polyvinylchloride (PVC) under radiation field. An amount of hydrochloric acid is released in this reaction. A pH indicator, included in the system, changes its colour at different absorbed dose. The changes of colour happened in a certain pH interval called turning range. We used as pH indicator the RED CONGO colorant with turning range of pH = 3 to 5 (from blue to red). A schematic view of the qualitative dosimeter is given. The initial colour is red and it continuously changes to brown, at 1 kGy absorbed dose, and to blue-green, for 5-100 kGy. The main features of this qualitative dosimetric system are: - Quick and easy to read information about product passing through radiation field; - Absorbed dose range, 1-300 kGy; - Independence of absorbed dose rate in the interval 5-100 kGy/h; - Stability, 3 year in the dark and 1 year in sun light; - Good reproducibility. The preparation technology consists in the following steps: 1. Preparation of the solutions: a) PVC in cyclohexanone solution b) RED CONGO in water solution; 2. Preparation of the system support consisting in dropping the PVC solution on adhesive labels; 3. Sample preparation consists in dropping the colorant solution on the system support; 4. Batch trial tests. The trial test was performed at IETI 10000 irradiation plant belonging to IFIN-HH and the reference absorbed dose was determined by Fricke dosimetry. The

  15. Multi-dimensional dosimetric verification of stereotactic radiotherapy for uveal melanoma using radiochromic EBT film

    International Nuclear Information System (INIS)

    Sturtewagen, E.; Fuss, M.; Georg, D.; Paelinck, L.; Wagter, C. de

    2008-01-01

    plan quality assurance. EBT films are a suitable and reliable dosimetric tool that could replace traditionally used radiographic films. The presented acceptance criteria for SRT treatment plans might be used as a benchmarking data-set for other stereotactic applications and/or other equipment (planning system and delivery hardware) combinations. (orig.)

  16. MCID: A Software Tool to Provide Monte Carlo Driven Dosimetric Calculations Using Multimodality NM Images

    International Nuclear Information System (INIS)

    Vergara Gil, Alex; Torres Aroche, Leonel A; Coca Péreza, Marco A; Pacilio, Massimiliano; Botta, Francesca; Cremonesi, Marta

    2016-01-01

    Aim: In this work, a new software tool (named MCID) to calculate patient specific absorbed dose in molecular radiotherapy, based on Monte Carlo simulation, is presented. Materials & Methods: The inputs for MCID are two co-registered medical images containing anatomical (CT) and functional (PET or SPECT) information of the patient. The anatomical image is converted to a density map, and tissues segmentation is provided considering compositions and densities from ICRU 44 and ICRP; the functional image provides the cumulative activity map at voxel level (figure 1). MCID creates an input file for Monte Carlo (MC) codes such as MCNP5 and GATE, and converts the MC outputs into an absorbed dose image. Results: The developed tool allows estimating dose distributions for non-uniform activities distributions and non-homogeneous tissues. It includes tools for delineation of volumes of interest, and dosimetric data analysis. Procedures to decrease the calculation time are implemented in order to allow its use in clinical settings. Dose–volume histograms are computed and presented from the obtained dosimetric maps as well as dose statistics such as mean, minimum and maximum dose values; the results can be saved in common medical image formats (Interfile, DICOM, Analyze, MetaImage). The MCID was validated by comparing estimated dose values versus reference data, such as gold standards phantoms (OLINDA´s spheres) and other MC simulations of non-homogeneous phantoms. A good agreement was obtained in spheres ranged 1g to 1kg of mass and in non-homogeneous phantoms. Clinical studies were also examined. Dosimetric evaluations in patients undergoing 153Sm-EDTMP therapy for osseous metastases showed non-significant differences with calculations performed by traditional methods. The possibility of creating input files to perform the simulations using the Gate Code has increased the MCID applications and improved its functionality, Different clinical situations including PET and SPECT

  17. Dosimetric studies, spectrometric, radiographic, metallographic of a new argentinean seed of 125 I used in brachytherapy

    International Nuclear Information System (INIS)

    Pirchio, R.; Saravi, M.; Banchik, D.; Munoz, C.

    2006-01-01

    A new source of 125 I model Braquibac TM has been developed in Argentina for applications in interstitial brachytherapy. The AAPM Task Group 43 (TG-43) recommends that dosimetric characteristics of new sources of brachytherapy of Iodine-125 have been theoretically and experimentally determined before its clinical use. The objectives outlined in this work were the study of the design of the new seed, the calculation of dosimetric parameters and the photons spectra analysis. Its were carried out radiographic and metallographic studies to determine the physical characteristics of the source. For the realization of the dosimetric calculations it was used the Monte Carlo code MCNP5. Values of the radial dose function, g(r), of the constant of dose rate, Λ, of the function of anisotropy of two dimensions, F(r, θ), of the factor and constant of anisotropy its were obtained simulating the source in water according to the recommended methodology in TG-43. The constant of dose rate is similar to 0,880 ± 0,080 c Gy h -1 U -1 . The kerma in air rate of reference, S K , was calculated as 1,036 c Gy cm 2 h -1 mCi -1 simulating the seed in dry air. Its were carried out spectrometric studies using a semiconductor planar detector of HPGe (high purity germanium). Photons spectra showed characteristic x-rays of 125 I with energies of 27,20 keV, 27,47 keV, 31 keV and 31,70 keV gamma photons of 35,5 keV, and x-ray fluorescent coming from the silver nucleus of 22,10 keV, 24,94 keV and 25,45 keV. The angular dependence of the intensity of photons around the seed and in air it was analyzed with the planar detector. This was carried out to study the anisotropy in the photons flow due to variation in the thickness of the titanium wall and of the welding, movements of the silver tube inside the source and deposition of the radioactive material on the silver tube. (Author)

  18. Clinical efficiency, image quality and dosimetric considerations

    Energy Technology Data Exchange (ETDEWEB)

    Arreola, M. [Director of Clinical Radiological Physics, Shands Hospital at the University of Florida College of Medicine, Gainesville, FL (United States)

    2000-07-01

    plateau, the versatility of multi-planar and 3D reconstruction has reestablished CT as the modality of preference in many clinical applications. Finally, this work focuses on patient dose issues as a result of the constant changes and improvements in CT technology and clinical application, showing how typical patient doses per study have increased (at times, significantly) in newer generations and how they have decreased in other instances, with a current trend on decreased dose per scanned series but an increase per study, (Author)

  19. Clinical efficiency, image quality and dosimetric considerations

    International Nuclear Information System (INIS)

    Arreola, M.

    2000-01-01

    plateau, the versatility of multi-planar and 3D reconstruction has reestablished CT as the modality of preference in many clinical applications. Finally, this work focuses on patient dose issues as a result of the constant changes and improvements in CT technology and clinical application, showing how typical patient doses per study have increased (at times, significantly) in newer generations and how they have decreased in other instances, with a current trend on decreased dose per scanned series but an increase per study, (Author)

  20. Radioecological and dosimetric consequences of the Chernobyl accident in France

    International Nuclear Information System (INIS)

    Renaud, Ph.; Beaugelin, K.; Maubert, H.; Ledenvic, Ph.

    1997-11-01

    This study has as objective a survey of the radioecological and dosimetric consequences of the Chernobyl accident in France, as well as a prognosis for the years to come. It was requested by the Direction of Nuclear Installation Safety (DSIN) in relation to different organisms which effected measurements after this accident. It is based on the use of combined results of measurements and modelling by means of the code ASTRAL developed at IPSN. Various measurements obtained from five authorities and institutions, were made available, such as: activity of air and water, soil, processed food, agricultural and natural products. However, to achieve the survey still a modelling is needed. ASTRAL is a code for evaluating the ecological consequences of an accident. It allows establishing the correspondence between the soil Remnant Surface Activities (RSA, in Bq.m -2 ), the activity concentration of the agricultural production and the individual and collective doses resulting from external and internal exposures (due to inhalation and ingestion of contaminated nurture). The results of principal synthesis documents on the Chernobyl accident and its consequences were also used. The report is structured in nine sections, as follows: 1.Introduction; 2.Objective and methodology; 3.Characterization of radioactive depositions; 4;Remnant surface activities; 5.Contamination of agricultural products and foods; 6.Contamination of natural, semi-natural products and of drinking water; 7.Dosimetric evaluations; 8.Proposals for the environmental surveillance; 9.Conclusion. Finally, after ten years, one concludes that at present the dosimetric consequences of the Chernobyl accident in France were rather limited. For the period 1986-2046 the average individual effective dose estimated for the most struck zone is lower than 1500 μSv, which represents almost 1% of the average natural exposure for the same period. At present, the cesium 137 levels are at often inferior to those recorded before

  1. Energy dependence corrections to MOSFET dosimetric sensitivity

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Crown St, Wollongong

    2009-01-01

    Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to reading to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

  2. Energy dependence corrections to MOSFET dosimetric sensitivity.

    Science.gov (United States)

    Cheung, T; Butson, M J; Yu, P K N

    2009-03-01

    Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6 MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to readings to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

  3. Desarrollo de aleaciones multifuncionales con base titanio

    OpenAIRE

    Pareja, Ramiro

    2007-01-01

    El Laboratorio de Materiales Nano-estructurados y Multifuncionales del Departamento de Física de la Universidad Carlos III de Madrid se dedica al desarrollo, procesado y caracterización de aleaciones con propiedades mejores que las preparadas por métodos convencionales. La mejora de las propiedades se consigue produciendo las aleaciones con un tamaño de grano nanométrico o ultrafino, o introduciendo una dispersión de nano-partículas de óxido en la matriz. El grupo está interesado en algún tip...

  4. Desarrollo de aplicaciones para Windows Phone

    OpenAIRE

    Castellanos de la Torre, Francisco José

    2013-01-01

    Desarrollar una aplicación para dispositivos móviles no es una tarea sencilla, ya que precisamos no solo tener conocimientos de programación, sino que también tenemos que familiarizarnos muy bien con el entorno de desarrollo y el sistema operativo para el cual pretendemos crear la aplicación. Esto consiste en conocer en profundidad tanto las características técnicas de los dispositivos como las distintas APIs que tenemos a nuestra disposición. Hemos elegido Windows Phone 7.5 porque ha sido...

  5. SCODA para el Desarrollo de Sistemas Multiagente

    OpenAIRE

    Román Gallego, Jesús Ángel; Tapia Martínez, Dante I.; Corchado Rodríguez, Juan M.

    2017-01-01

    El planteamiento de implementar sistemas multiagente de forma que puedan reutilizarse con distintos objetivos, dota a los desarrolladores de una metodología más eficaz en sus fines. Este artículo presenta SCODA, una arquitectura basada en cinco principios: estandaridad, especialización, facilidad de implementación, reutilización y computación distribuida. SCODA pretende facilitar el desarrollo de sistemas multiagente, basándose en el concepto de pequeños grupos de agentes denominados Comunida...

  6. Desarrollo de un sistema de reconocimiento facial

    OpenAIRE

    Vivas Imparato, Abdón Alejandro

    2014-01-01

    El objetivo principal alrededor del cual se desenvuelve este proyecto es el desarrollo de un sistema de reconocimiento facial. Entre sus objetivos específicos se encuentran: realizar una primera aproximación sobre las técnicas de reconocimiento facial existentes en la actualidad, elegir una aplicación donde pueda ser útil el reconocimiento facial, diseñar y desarrollar un programa en MATLAB que lleve a cabo la función de reconocimiento facial, y evaluar el funcionamiento del sistema desarroll...

  7. Ecología y desarrollo humano

    OpenAIRE

    Mallarach, J.M. (Josep M.); Trigo, T. (Tomás); Puig-i-Baguer, J. (Jordi); Ferrero, I. (Ignacio); Melé, D. (Domènec); Moreno Ibáñez, A. (Antonio); Ariño, A.H. (Arturo H.); López, D. (Dolores); Sánchez-Ostiz, A. (Ana); Lorda, J. L. (Juan Luis); Duro-Rivas (coord.), R. (Reyes); Aulestiarte (coord.), S. (Susana)

    2017-01-01

    Con motivo de la publicación de la Encíclica "Laudato si'. Sobre el cuidado de la casa común" del Papa Francisco, la Universidad de Navarra organizó el 18 de marzo de 2016 una jornada interdisciplinar titulada "Ecología y desarrollo humano. Conversaciones sobre Laudato si'". La jornada pretendía incitar tanto al estudio y la profundización intelectual como al compromiso práctico acerca de las propuestas formuladas en la Encíclica. Se recogen en esta publicación los textos de las intervencione...

  8. Etnicidad y desarrollo en el Altiplano las organizaciones mayas de desarrollo de Guatemala

    OpenAIRE

    Jordi Sánchez, Ángel Mario

    2003-01-01

    El presente trabajo de tesis doctoral se ocupa del análisis del modelo de desarrollo puesto en práctica por una serie de organizaciones indígenas ubicadas en el occidente de Guatemala. El estudio de dicho modelo (que hemos calificado como de etnodesarroll

  9. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-01-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA

  10. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy.

    Science.gov (United States)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-09-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA.

  11. Dosimetric comparison of intensity modulated radiosurgery with dynamic conformal arc radiosurgery for small cranial lesions

    Directory of Open Access Journals (Sweden)

    Juan F Calvo-Ortega

    2016-01-01

    Conclusions: We have shown that IMRS provides the dosimetric advantages compared with DCARS. Based on the dosimetric findings in this study, fixed gantry IMRS technique can be adopted as a standard procedure for cranial SRS when micro-MLC technology is not available on the linear accelerator.

  12. Dosimetric confirmation of a software for the design of radiotherapy

    International Nuclear Information System (INIS)

    Alfonso, R.; Huerta, U.; Torres, M.; Alonso, J.L.

    1995-01-01

    A software for radiotherapy treatment has been recently designed by specialists in medical physics form Hermanos Ameijeiras Clinical and Surgical Hospital. Several locations in the distributions of dose calculations. The results of dosimetric measurements with TLD-700 powder in a human-like manikin were taken as reference. The different options available for the entry of patients shape data are explained. A comparison of the results of measurements with calculations, is presented. Causes of discrepancies are analyzed and recommendations regarding the usefulness of the different for the collection of data from patients are made

  13. Dosimetric measurement of the disintegration rate of fission products

    International Nuclear Information System (INIS)

    Solymosi, J.; Nagy, L.G.; Zagyvai, P.

    1992-01-01

    Investigations on the disintegration rate of fission products of 238 U and 239 Pu are presented. The intensity of the β-and γ-radiation of fission products were measured continously in an interval of 1-1300 hours following the fission, offering the possibility for determining the general and specific characteristics of the individual fission products. A universal measuring procedure was elaborated for the rapid in situ determination of the dosimetric features of fission products, which is suitable for the accurate evaluation and prediction of external absorbed dose even in case of fission products of various origin and unknown composition. (author) 6 refs.; 7 figs.; 1 tab

  14. On the set up of a thermoluminescent dosimetric system

    International Nuclear Information System (INIS)

    Furetta, C.

    2000-01-01

    In this work are treated the following features: Introduction to the thermoluminescent dosimetric systems, their prerequisites, Initialisation procedure, Batch homogeneity, Procedure for batch homogeneity (IEC), Reference and field dosimeters, Thermal treatments and its general considerations, as well as its initialisation treatment, erasing treatment or standard annealing (also called pre-irradiation annealing), post-irradiation or pre-readout annealing. Also is presented the performance of the annealing study, with its suggested procedures such as: a first and second procedures. Finally, it is showed about experimental data of the annealing treatments and its diagrams. (Author)

  15. Radioecological and dosimetric consequences of Chernobyl accident in France

    International Nuclear Information System (INIS)

    Renaud, Ph.; Beaugelin, K.; Maubert, H.; Ledenvic, Ph.

    1997-01-01

    After ten years and the taking in account of numerous data, it can be affirmed that the dosimetric consequences of Chernobyl accident will have been limited in France. for the period 1986-2046, the individual middle efficient dose commitment, for the area the most reached by depositing is inferior to 1500 μSv, that represents about 1% of middle natural exposure in the same time. but mountains and forests can have more important surface activities than in plain. Everywhere else, it can be considered that the effects of Chernobyl accident are disappearing. the levels of cesium 137 are now often inferior to what they were before the accident. (N.C.)

  16. Dosimetric evaluation of Radiotherapy units wit 60Co

    International Nuclear Information System (INIS)

    Leon, B. Salinas de; Tovar M, V.; Becerril V, A.

    2000-01-01

    The SSDL network of the IAEA performs, every year, quality audit tests for radiotherapy services ( 60 Co units and linear accelerators), and for national SSDL as well. Because of the SSDL-Mexico results in these tests and due to our enthusiasm and confidence in our work, a parallel test has been done , which is described in this talk as well as the results. Nowadays, a second parallel test goes up, which could confirm our optimism and open the possibility to our country to start a national dosimetric audit of 60 Co radiotherapy units. (Author)

  17. The pitfalls of dosimetric commissioning for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Tohyama, Naoki; Kodama, Takashi; Hatano, K.

    2013-01-01

    Intensity modulated radiation therapy (IMRT) allows higher radiation dose to be focused to the target volumes while minimizing the dose to OAR. To start of clinical treatment in IMRTvwe must perform commissioning strictly than 3D-conformal radiotherapy (CRT). In this report, pitfalls of dosimetric commissioning for intensity modulated radiation therapy were reviewed. Multileaf collimator (MLC) offsets and MLC transmissions are important parameters in commissioning of RTPS for IMRT. Correction of depth scaling and fluence scaling is necessary for dose measurement using solid phantom. (author)

  18. Method of accounting and suppressing the instability of dosimetric information

    International Nuclear Information System (INIS)

    Fejtek, Ya.

    1977-01-01

    To account for dosimetric information instability differential and integral correcting factors are proposed. The differential factor converts signals of dosimeters irradiated during short but different periods of time into equivalent signals related to a certain period of time. The factor excludes the effect of signal instability in the case of short exposures. The integral factor represents a generalization of the differential one for prolonged exposures. The statistical integral factor is derived. An example of processing experimental data using the analytical method developed is presented. The method is pointed out to have been introduced in the state personal dosimetry service in Czechoslovakia [ru

  19. Dosimetric study of a new polymer encapsulated palladium-103 seed

    International Nuclear Information System (INIS)

    Bernard, S; Vynckier, S

    2005-01-01

    The use of low-energy photon emitters for brachytherapy applications, as in the treatment of prostate or ocular tumours, has increased significantly over the last few years. Several new seed models utilizing 103 Pd and 125 I have recently been introduced. Following the TG43U1 recommendations of the AAPM (American Association of Physicists in Medicine) (Rivard et al 2004 Med. Phys. 31 633), dose distributions around these low-energy photon emitters are characterized by the dose rate constant, the radial dose function and the anisotropy function in water. These functions and constants can be measured for each new seed in a solid phantom (i.e. solid water such as WT1) using high spatial resolution detectors such as very small thermoluminescent detectors. These experimental results in solid water must then be converted into liquid water by using Monte Carlo simulations. This paper presents the dosimetric parameters of a new palladium seed, OptiSeed TM (produced by International Brachytherapy (IBt), Seneffe, Belgium), made with a biocompatible polymeric shell and with a design that differs from the hollow titanium encapsulated seed, InterSource 103 , produced by the same company. A polymer encapsulation was chosen by the company IBt in order to reduce the quantity of radioactive material needed for a given dose rate, and to improve the symmetry of the radiation field around the seed. The necessary experimental data were obtained by measurements with LiF thermoluminescent dosimeters (1 mm 3 ) in a solid water phantom (WT1) and then converted to values in liquid water using Monte Carlo calculations (MCNP-4C). Comparison of the results with a previous study by Reniers et al (2002 Appl. Radiat. Isot. 57 805) shows very good agreement for the dose rate constant and for the radial dose function. In addition, the results also indicate an improvement in isotropy compared to a conventional titanium encapsulated seed. The relative dose (anisotropy value relative to 90 deg.) from

  20. Dosimetric Effects of Air Pockets Around High-Dose Rate Brachytherapy Vaginal Cylinders

    International Nuclear Information System (INIS)

    Richardson, Susan; Palaniswaamy, Geethpriya; Grigsby, Perry W.

    2010-01-01

    Purpose: Most physicians use a single-channel vaginal cylinder for postoperative endometrial cancer brachytherapy. Recent published data have identified air pockets between the vaginal cylinders and the vaginal mucosa. The purpose of this research was to evaluate the incidence, size, and dosimetric effects of these air pockets. Methods and Materials: 25 patients receiving postoperative vaginal cuff brachytherapy with a high-dose rate vaginal cylinders were enrolled in this prospective data collection study. Patients were treated with 6 fractions of 200 to 400 cGy per fraction prescribed at 5 mm depth. Computed tomography simulation for brachytherapy treatment planning was performed for each fraction. The quantity, volume, and dosimetric impact of the air pockets surrounding the cylinder were quantified. Results: In 25 patients, a total of 90 air pockets were present in 150 procedures (60%). Five patients had no air pockets present during any of their treatments. The average number of air pockets per patient was 3.6, with the average total air pocket volume being 0.34 cm 3 (range, 0.01-1.32 cm 3 ). The average dose reduction to the vaginal mucosa at the air pocket was 27% (range, 9-58%). Ten patients had no air pockets on their first fraction but air pockets occurred in subsequent fractions. Conclusion: Air pockets between high-dose rate vaginal cylinder applicators and the vaginal mucosa are present in the majority of fractions of therapy, and their presence varies from patient to patient and fraction to fraction. The existence of air pockets results in reduced radiation dose to the vaginal mucosa.

  1. Attainment of dosimetric pediatrics grandeur to computed tomography examinations of the abdomen

    International Nuclear Information System (INIS)

    Jormada, Tiago S.

    2013-01-01

    Currently, 10% of all computerized tomography exams (CT) are made in pediatric patients. In developed countries, the practice of obtaining the dosimetric quantities (weighted index dose C w , index air kerma volumetric C vol product kerma-length P KL , CT ) and effective dose (E) in pediatric CT scans is common. In Brazil, data like these are practically nonexistent. The goal of this work is to obtain the dosimetric quantities and the dose effective in pediatric CT scans, and study its application in the optimization process. The study took place in a thermographs' Toshiba Asteion Single-Slice and a GE Brightsped's multi-slice where measurements were made with type pencil ionization chamber and a trunk's phantom of PMMA with diameter of 16 cm. In single-slice CT scanner, the results obtained for the C vol , P KL , CT and E were 18.73 mGy, 15.61 mGy and 6.87 mSv mGy.cm 343.51, respectively, whereas in multi-slice CT scanner the results were 18.81 mGy, 20.07 mGy, 441.64 mGy.cm and 8,83 mSv. There was no significant difference between the values of C w obtained already in the values of the Cvol, P KL , CT and E dose the differences between the results were quite significant. Comparing the C w and P KL , CT and with the values recommended by UCRP 87 (25 mGy for C vol and 360 mGy.cm for P KL , CT in pediatric CT scans of the abdomen), the two scanners were below reference levels for C w and not require an start on process of optimization. (author)

  2. TL and OSL dosimetric properties of Opal gemstone for gamma radiation dosimetry

    International Nuclear Information System (INIS)

    Antonio, Patrícia L.; Gronchi, Claudia C.; Oliveira, Raquel A.P.; Khoury, Helen J.; Caldas, Linda V.E.

    2016-01-01

    In this work, the response of the natural material Opal was studied in relation to its thermoluminescence (TL) and optically stimulated luminescence (OSL), after exposure to the gamma radiation of a "6"0Co source. The structure of the powdered Opal was verified using the X-ray diffraction, scanning electronic microscopy and energy-dispersive X-ray spectroscopy techniques. The material, in its stone form, was turned into powder and mixed to Teflon (also in powder) in three different concentrations, and then pellets were manufactured. The aim of this work was to evaluate the response of these pellets in high-doses of gamma radiation beams, and to observe their possible application as dosimeters, using the TL and OSL techniques. The dosimetric properties of the samples were analyzed by means of different tests, as: TL emission curves and OSL signal decay curves, reproducibility of TL and OSL response, minimum detectable dose, TL and OSL dose–response curves (5 Gy–10 kGy), and fading. The results obtained in this work, for the TL and OSL phenomena, demonstrated that the pellets of Opal + Teflon present an adequate performance e possibility of use as dosimeters in beams of high-dose gamma radiation. - Highlights: • The XRD, SEM and EDX techniques were used to investigate powdered Opal. • Pellets of three different concentrations of Opal and Teflon were studied. • The dosimetric properties of the Opal + Teflon pellets were verified. • TL and OSL techniques were used to analyze the characteristics of the pellets. • Pellets of concentration of 2:1 (Opal:Teflon) presented the most adequate results.

  3. SU-F-T-240: EPID-Based Quality Assurance for Dosimetric Credentialing

    Energy Technology Data Exchange (ETDEWEB)

    Miri, N [University of Newcastle, Newcastle, NSW (Australia); Lehmann, J [Calvary Mater Newcastle, Newcastle, NSW (Australia); Vial, P [Liverpool Hospital, Sydney, NSW (Australia); Greer, P [Calvary Mater Newcastle, Newcastle, NSW (Australia); University of Newcastle, Newcastle, NSW (Australia)

    2016-06-15

    Purpose: We propose a novel dosimetric audit method for clinical trials using EPID measurements at each center and a standardized EPID to dose conversion algorithm. The aim of this work is to investigate the applicability of the EPID method to different linear accelerator, EPID and treatment planning system (TPS) combinations. Methods: Combination of delivery and planning systems were three Varian linacs including one Pinnacle and two Eclipse TPS and, two ELEKTA linacs including one Pinnacle and one Monaco TPS. All Varian linacs had the same EPID structure and similarly for the ELEKTA linacs. Initially, dose response of the EPIDs was investigated by acquiring integrated pixel value (IPV) of the central area of 10 cm2 images versus MUs, 5-400 MU. Then, the EPID to dose conversion was investigated for different system combinations. Square field size images, 2, 3, 4, 6, 10, 15, 20, 25 cm2 acquired by all systems were converted to dose at isocenter of a virtual flat phantom then the dose was compared to the corresponding TPS dose. Results: All EPIDs showed a relatively linear behavior versus MU except at low MUs which showed irregularities probably due to initial inaccuracies of irradiation. Furthermore, for all the EPID models, the model predicted TPS dose with a mean dose difference percentage of 1.3. However the model showed a few inaccuracies for ELEKTA EPID images at field sizes larger than 20 cm2. Conclusion: The EPIDs demonstrated similar behavior versus MU and the model was relatively accurate for all the systems. Therefore, the model could be employed as a global dosimetric method to audit clinical trials. Funding has been provided from Department of Radiation Oncology, TROG Cancer Research and the University of Newcastle. Narges Miri is a recipient of a University of Newcastle postgraduate scholarship.

  4. First approval procedure of the TL dosimetric service of the NPP in Slovenia

    International Nuclear Information System (INIS)

    Janzekovic, H.; Krizman, M.; Pucelj, B.; Stuhec, M.; Zdesar, U.

    2001-01-01

    The individual dosimetry of exposed workers in a NPP is one of the essential parts which demonstrates the radiation protection standards achieved in a facility. According to the current legislation the Ministry of Health of the Republic of Slovenia has the authority to grant approvals to personal dosimetric services which perform the dosimetric monitoring of workers in Slovenia. Due to the fact that the detailed approval procedure is not given in national regulations, the Ministry of Health in 2000 established a group of experts with the task to prepare technical and organising requirements for such approval. Based on international documents [1,2,3] the Approval procedure for the thermoluminescence dosimetric (TL) services was created. Following this procedure the assessment of the TL dosimetric service in the NPP was performed. The problems related to the technical and organising requirements with the emphasise on the QA/QC criteria of the TL dosimetric service will be discussed.(author)

  5. El mecanismo de Desarrollo Limpio : oportunidades de Desarrollo Sostenible para Países en Desarrollo en el Protocolo de Kioto. Caso Colombia como posible potencia continental ambiental

    OpenAIRE

    Betancourt Mesa, Juan Manuel

    2009-01-01

    El Cambio Climático y los Mecanismos de Desarrollo Limpio (MDL) en Colombia: Con el protocolo de Kyoto nacen los Mecanismos de Desarrollo Limpio, los cuales posibilitan a los países en desarrollo el generar cambios en los modelos de producción de las industrias altamente contaminantes por producciones limpias, obteniendo beneficios adicionales por la comercialización de los títulos de Reducciones Certificadas de las Emisiones (RCE). Nuestro país, tiene un potencial importante para fomentar el...

  6. ESTRATEGIAS COMPETITIVAS: FACTOR CLAVE DE DESARROLLO

    Directory of Open Access Journals (Sweden)

    Luisa Quero

    2008-07-01

    Full Text Available El propósito de esté articulo fue analizar la estrategia competitiva como factor clave de desarrollo, para ello se llevó a cabo una revisión bibliográfica que permitió conocer aspectos fundamentales de las estrategias competitivas como herramienta importante dentro de cualquier organización que le permita obtener ventajas competitivas frente a otros mercados para tratar de obtener un alto nivel de desarrollo. Los resultados obtenidos a través del estudio documental revelaron la existencia de autores que observan que las organizaciones grandes o pequeñas requieren establecer o formular estrategias competitivas como mecanismo de apoyo para la identificación de nuevas oportunidades, así mismo consideran que estas deberían mantenerse con éxito en otros mercados a largo plazo.

  7. EL DESARROLLO LOCAL EN SU LABERINTO

    Directory of Open Access Journals (Sweden)

    Arnoldo Oscar Delgado

    2010-01-01

    Full Text Available Desde su instalación en nuestro país, teoría y práctica del desarrollo local han sido objeto de asimilaciones diversas que, por momentos, contribuyeron a diluir un rasgo esencial de aquellos conglomerados de Pequeñas y Medianas Empresas (PYMES que fundaron el interés por lo local en la década de 1970: la continua innovación de productos y procesos productivos, sólo posible por la impronta de los factores culturales en la constitución de un entorno socio-institucional autorregulado para favorecerla. La etapa iniciada en 2003 pareciera correr riesgo similar: con el objetivo de revertir las pavorosas consecuencias de la década precedente y lograr crecimiento con inclusión, se asimila ahora a la economía social procurando superar el mero asistencialismo y conformar una malla socio-productiva basada en lazos de solidaridad y cooperación. Más allá de la legitimidad del planteo, la precariedad del escenario subyacente evidencia la brecha que aún nos separa de aquel modelo ideal, emplazándonos a acordar seriamente una política de estado a mediano y largo plazo para fomentar un desarrollo territorial acorde con las exigencias de la sociedad contemporánea.

  8. Condiciones motivacionales y desarrollo de carrera

    Directory of Open Access Journals (Sweden)

    Ana Cristina Marín Fernández

    2005-01-01

    Full Text Available El artículo que se presenta a continuación recoge las conclusiones del trabajo de investigación realizado al interior del programa de desarrollo profesional PDP de la Universidad Icesi, que posibilitó la sistematización y estudio de los perfiles motivacionales recopilados semestralmente de 1997 hasta el 2004. Adicionalmente el estudio se enriquece con la experiencia propia del programa en cuanto a ubicación de estudiantes en el medio laboral, el seguimiento personalizado a los practicantes y la relación permanente con las empresas. Mediante el uso del CMT (cuestionario de motivación para el trabajo se establece el perfil motivacional de practicantes de la Universidad Icesiy las particularidades de dicho perfil diferenciadas por carreras, lo que permite sensibilizarse ante la oportunidad que representa el conocimiento de las tendencias y características de los perfiles motivacionales de diferentes disciplinas frente ala gestión del talento humano en las organizaciones. Para concluir, el artículo presenta a manera de ejemplo la experiencia de la Universidad en relación con el proyecto educativo institucional como generador de condiciones motivacionales y plantea algunas acciones que esperamos sean oportunas al momento de responder a las expectativas y necesidades de desarrollo profesional.

  9. CAMBIO DE LAS INSTITUCIONES PARA EL DESARROLLO

    Directory of Open Access Journals (Sweden)

    Antonio Vázquez Barquero

    2006-06-01

    Full Text Available Existe un amplio acuerdo sobre que el funcionamiento de las instituciones determina la evolución de las economías y la senda específica de crecimiento de las ciudades y países; es decir, que las normas y reglas, formales (como los contratos y los acuerdos entre empresas y actores pero también informales (como los códigos de conducta y las convenciones, existentes en cada sociedad, juegan un papel estratégico en los procesos de desarrollo. Las empresas y las organizaciones toman sus decisiones de inversión en un entorno institucional y las realizan a través de un sistema de relaciones e interacciones con otras empresas y organizaciones, que forman el sistema institucional, lo que afecta a los resultados de la inversión, y, por lo tanto, al comportamiento de la productividad y al propio proceso de desarrollo económico (Vázquez Barquero, 2005.  

  10. POBREZA, RECURSOS HUMANOS Y DESARROLLO SOSTENIBLE

    Directory of Open Access Journals (Sweden)

    Jorge Mora Alfaro

    2011-09-01

    Full Text Available Dos desafíos de enorme trascendencia enfrentan América Latina y el Caribe al arribar al siglo XXI: por un lado, crear las condiciones apropiadas para insertarse con éxito en el interconectado, competitivo y exigente mundo contemporáneo. Por otro lado, superar los obstáculos al logro de la aspiración del desarrollo humano sostenible, entre los que sobresale la ausencia de mecanismos eficaces de distribución del ingreso y la significativa cantidad de seres humanos sumidos en la pobreza y las privaciones.Estas dos dimensiones del desarrollo regional se encuentran estrechamente entrelazadas y mutuamente condicionadas. Una distribución más equitativa del ingreso contribuye a elevar la movilidad social, el acceso a la educación, el aumento de la productividad y la estabilidad, aspectos esenciales para acrecentar la capacidad competitiva y para lograr una inserción de calidad en el contexto internacional. Una estrategia de integración en el contexto internacional, sustentada en las fortalezas nacionales, en la identidad cultural y en el capital humano, posibilita la sostenibilidad y la distribución de los beneficios entre los diversos estratos de la sociedad.

  11. Desarrollo urbano sostenible y criterios de diseño urbano

    OpenAIRE

    Higueras García, Esther

    2013-01-01

    DESARROLLO URBANO SOSTENIBLE Y CRITERIOS DE DISEÑO URBANO .- Consecuencias de la urbanización sobre el territorio .- Principales problemas del crecimiento actual .- El desarrollo sostenible .- Diez principios para el desarrollo sostenible

  12. Dosimetric characteristics of muscovite mineral studied under different annealing conditions

    International Nuclear Information System (INIS)

    Kalita, J M; Wary, G

    2015-01-01

    The annealing effect on the thermoluminescence (TL) characteristics of x-ray irradiated muscovite mineral relevant to dosimetry has been studied. For un-annealed and 473 K annealed samples an isolated TL peak has been observed at around 347 K; however, annealing at 573, 673 and 773 K two composite peaks have been recorded at around 347 and 408 K. Kinetic analysis reveals that there is a trap level at a depth of 0.71 eV, and due to annealing at 573 K (or above), a new trap level generates at 1.23 eV. The dosimetric characteristics, such as dose response, fading and reproducibility, have been studied in detail for all types of samples. The highest linear dose response has been observed from 10 to 2000 mGy in the 773 K annealed sample. Due to generation of the deep trap level, fading is found to reduce significantly just after annealing above 573 K. Reproducibility analysis shows that after 10 cycles of reuse the coefficient of variations in the results for 60, 180 and 1000 mGy dose irradiated 773 K annealed samples are found to be 1.78%, 1.37% and 1.58%, respectively. These analyses demand that after proper annealing muscovite shows important dosimetric features that are essentially required for a thermoluminescence dosimeter (TLD). (paper)

  13. Quantitative analysis of patient-specific dosimetric IMRT verification

    International Nuclear Information System (INIS)

    Budgell, G J; Perrin, B A; Mott, J H L; Fairfoul, J; Mackay, R I

    2005-01-01

    Patient-specific dosimetric verification methods for IMRT treatments are variable, time-consuming and frequently qualitative, preventing evidence-based reduction in the amount of verification performed. This paper addresses some of these issues by applying a quantitative analysis parameter to the dosimetric verification procedure. Film measurements in different planes were acquired for a series of ten IMRT prostate patients, analysed using the quantitative parameter, and compared to determine the most suitable verification plane. Film and ion chamber verification results for 61 patients were analysed to determine long-term accuracy, reproducibility and stability of the planning and delivery system. The reproducibility of the measurement and analysis system was also studied. The results show that verification results are strongly dependent on the plane chosen, with the coronal plane particularly insensitive to delivery error. Unexpectedly, no correlation could be found between the levels of error in different verification planes. Longer term verification results showed consistent patterns which suggest that the amount of patient-specific verification can be safely reduced, provided proper caution is exercised: an evidence-based model for such reduction is proposed. It is concluded that dose/distance to agreement (e.g., 3%/3 mm) should be used as a criterion of acceptability. Quantitative parameters calculated for a given criterion of acceptability should be adopted in conjunction with displays that show where discrepancies occur. Planning and delivery systems which cannot meet the required standards of accuracy, reproducibility and stability to reduce verification will not be accepted by the radiotherapy community

  14. Determination of dosimetric quantities in pediatric abdominal computed tomography scans

    Energy Technology Data Exchange (ETDEWEB)

    Jornada, Tiago da Silva [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Dept. de Diagnostipo por Imagem; Silva, Teogenes Augusto da, E-mail: silvata@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2014-09-15

    Objective: aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods: the study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results: No significant difference was observed in the values for weighted air kerma index (C{sub W}), but the differences were relevant in values for volumetric air kerma index (C{sub VOL}), air kerma-length product (P{sub KL,CT}) and effective dose. Conclusion: Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, P{sub KL,CT} and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. (author)

  15. Quality control of dosimetric systems using thermoluminescent crystals

    International Nuclear Information System (INIS)

    Mahecha, L.; Plazas, M. C.; Machado, M.; Perea, M. D.

    2006-01-01

    To achieve an optimal tumoral control to prostate cancer in early and locally advanced stages, it is necessary to increase the dose with a low mobility probability at the vesicle an rectal level. This is achieved through conformal radiotherapy. The Instituto Nacional de Cancerologia uses this technique, but two questions arise from the medical-physicists and medical radio-oncologist: In accordance with clinical protocols, the conformal radiotherapy delivers a low dose to the adjacent healthy tissues. What experimental method exists that can prove with certainly the veracity of this affirmation?. And, Do the dosimetric simulation system calculate suitable the dose for each tissues?. Through thermoluminescent dosimetry and the use of a physical simulator,we measured the absorbed dose at the target volume and the adjacent tissues using conformal and conventional radiotherapy. We proved that organs such as the rectum and bladder, receiver a minor dose in conformal radiotherapy, hence reducing their mobility probability. In addition, the readings from the thermoluminescent dosimeters and the doses calculated by the ECLIPSE dosimetric system were compared, concluding that the patient's prescribed dose is effectively delivered as recommended by the quality control program in radiotherapy. (Author)

  16. Comprehensive Australasian multicentre dosimetric intercomparison: issues, logistics and recommendations.

    Science.gov (United States)

    Ebert, M A; Harrison, K M; Cornes, D; Howlett, S J; Joseph, D J; Kron, T; Hamilton, C S; Denham, J W

    2009-02-01

    The present paper describes the logistics of the 2004-2008 Australasian Level III Dosimetry Intercomparison. Dosimetric intercomparisons (or 'audits') can be used in radiotherapy to evaluate the accuracy and quality of radiation delivery. An intercomparison was undertaken in New Zealand and Australia to evaluate the feasibility and logistics of ongoing dosimetric intercomparisons that evaluate all steps in the radiotherapy treatment process, known as a 'Level III' intercomparison. The study commenced in 2002 with the establishment of a study team, definition of the study protocol, acquisition of appropriate equipment and recruitment of participating radiotherapy centres. Measurements were undertaken between October 2004 and March 2008, and included collation of data on time, costs and logistics of the study. Forty independent Australian and New Zealand radiotherapy centres agreed to participate. Measurement visits were made to 37 of these centres. Data is presented on the costs of the study and the level of support required. The study involved the participation of 16 staff at the study centre who invested over 4000 hours in the study, and of over 200 professionals at participating centres. Recommendations are provided for future phantom-based intercomparisons. It is hoped that the present paper will be of benefit to any centres or groups contemplating similar activities by identifying the processes involved in establishing the study, the potential hazards and pitfalls, and expected resource requirements.

  17. Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

    Science.gov (United States)

    Jornada, Tiago da Silva; da Silva, Teógenes Augusto

    2014-01-01

    Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

  18. Dosimetric verification of the intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Zou Huawei; Jia Mingxuan; Wu Rong; Xiao Fuda; Dong Xiaoqi

    2004-01-01

    Objective: To discuss the methods of the dosimetric verification in the intensity-modulated radiation therapy (IMRT) and insure correct execution of the IMRT planning in the clinical practice. Methods: The CMSFOCUS9200 inverse planning system was used to provide optimized 5-field IMRT treatment plans for the patients. A phantom was made from true water-equivalent material. The doses of the interesting points and isodose distributions of the interesting planes in the phantom were calculated using patients' treatment plan. The phantom was placed on the couch of the accelerator and was irradiated using the phantom's treatment planning data. The doses of interesting points were measured using a 0.23 cc chamber and the isodose distributions of interesting planes were measured using RIT 113 film dosimetry system in the phantom. The results were compared with those from calculation in planning system for verification. Results: The doses and isodose distributions measured by the chamber and the film were consistent with those predicted by the planning. The error between the measured dose and calculated dose in the interesting points was less than 3%. Conclusion: The dosimetric verification of IMRT is a reliable measure in the course of its implementation. (authors)

  19. Desarrollo multinivel: Implicaciones macro-regional, local y micro- regional

    Directory of Open Access Journals (Sweden)

    José Guadalupe Vargas Hernández

    2006-11-01

    Full Text Available Este trabajo se propone analizar las implicaciones del desarrollo en los niveles macro-regional, local y micro- regional, a partir de la hipótesis central de la teoría del desarrollo que plantea que el desarrollo económico traerá consigo el desarrollo político y social. Después de hacer de un acercamiento conceptual al desarrollo, se repasan brevemente las teorías del desarrollo existentes como herramientas de análisis de la realidad. En la discusión se concluye que los procesos de desarrollo locales y regionales requieren de una transformación sustancial de las relaciones negociadas entre los agentes económicos y los actores políticos. Ante el paulatino retroceso que en las sociedades contemporáneas está teniendo el Estado de bienestar, uno de los principales retos es el empoderamiento de las organizaciones sociales y comunitarias para que desempeñen activamente su rol en los procesos de desarrollo local y regional.

  20. PARA UNA LECTURA CRÍTICA DEL DESARROLLO HUMANO

    Directory of Open Access Journals (Sweden)

    Melisa Campana

    2013-01-01

    Full Text Available El presente trabajo propone una lectura crítica del discurso del desarrollo humano articulado por Amartya Sen en Desarrollo y Libertad , desde el enfoque de la gubernamentalidad. En primer lugar, se precisa la perspectiva teórica adoptada, haciendo hincapié en las particularidades de la razón gubernamental neoliberal, marco en el que emerge el discurso del desarrollo humano. Se rastrea, luego, un conjunto de premisas del modelo de la elección racional, que brinda elementos conceptuales al discurso del desarrollo humano. A partir de estas claves, se examina una serie de postulados vertebradores de la propuesta de Amartya Sen, a los fines de identificar algunos de los efectos que ha producido el discurso del desarrollo humano en términos de concepción de la pobreza y de los dispositivos de intervención sobre ella.

  1. Tolerance and development Tolerancia y desarrollo

    Directory of Open Access Journals (Sweden)

    Bula Jorge Iván

    1994-06-01

    Full Text Available One central obstacle in the way of modernizing societies in the Third World is the difficulty of combining tolerance and development the author studies the social, cultural and political conditions which favor social and economic development., avoiding economic reductionism of the kind which sees the market and economic growth as the only path to development as well as that which sees the disappearance of capitalism as the cure for all evils. Bula says that all societies are conflictive by nature, but some manage to solve their conflicts by consensus. In the Third World there are a number of economic and political interests opposed to
    the opening up of society", and progress towards equi ty and solidarity will only be achieved with contradiction and conflict". The challenge is therefore to form a "new paradigm" for democracy which gives values and qualitative growth priority over quantitative growth; one that prizes the quality of life and the environment. This is the task of society as a whole, from which the new social movements will produce the leading agents in the new paradigm.
    Un obstáculo central para construir sociedades modernas en el Tercer Mundo es la dificultad para combinar la tolerancia con el desarrollo. El autor estudia las condiciones sociales, culturales y políticas que favorecen el desarrollo social y económico, evitando el reduccionismo económico, tanto el que ve en el mercado y en el crecimiento la única vía para el desarrollo como el que ve en la desaparición del capitalismo la solución a todos los males. Afirma que todas las sociedades son conflictivas por naturaleza, aunque algunas han logrado resolver sus conflictos mediante consenso. En el tercer mundo existen numerosos intereses económicos y políticos que se oponen a la apertura de espacios sociales y sólo “a través de un proceso contradictorio y conflictivo se avanzará hacia una sociedad equitativa y solidaria”. Así el reto es configurar

  2. TEORÍA, CAMBIO SOCIAL Y DESARROLLO

    Directory of Open Access Journals (Sweden)

    Jairo Puentes Palencia

    2002-01-01

    Full Text Available Se exponen las principales tendencias del pensamiento social en América Latina a lo largo del siglo XX. El punto de partida es la conceptualización de la región, que va más allá de la delimitación histórico-geográfica, lo cual permite plantear la herencia histórica. Las concepciones del pensamiento social y de la sociología se pueden diferenciar a lo largo del siglo XX a través de tres etapas: la etapa de los "pensadores", la sociología "cientifista" y la sociología "crítica". A partir de las concepciones clásicas sobre el desarrollo surgen expresiones latinoamericanas sobre el mismo, a través de la escuela de cepalina, con sus posteriores desarrollos del estructuralismo, los planteamientos del marxismo ortodoxo y, en particular, la escuela de la dependencia. Otra escuela o enfoque, que si bien tiene su origen en los clásicos y se adapta a las condiciones de la región, es la teoría de la modernización, en la práctica del desarrollismo en sus componentes económico, social y político. A finales de los años ochenta y comienzos de los noventa, el sistema mundial adopta nuevas características: de la bipolaridad se pasa a la unipolaridad y/o globalización, lo cual deja "sin piso" escuelas como las de la dependencia y otros planteamientos radicales de izquierda. Ante el fracaso de la modernidad, o de algunas de sus promesas, América Latina se ve abocada al mundo de la globalización y, al mismo tiempo, al dilema mundial que busca el desarrollo social a través de dos grandes paradigmas: la globalización neoliberal o la globalización democrática, lo que significa un nuevo reto para la construcción de un pensamiento latinoamericano y para el siglo XXI.

  3. Advances in the development of interaction between the codes MCNPX and ANSYS Fluent and their fusion applications; Avances en el desarrollo de la interaccion entre los codigos MCNPX y ANSYS Fluente y sus aplicaciones para fusion

    Energy Technology Data Exchange (ETDEWEB)

    Colomer, C.; Salellas, J.; Ahmed, R.; Fabbrio, M.; Aleman, A.

    2012-07-01

    The advances are presented in the project for the development of a code of interaction between MCNPX y el ANSYS Fluent. Following the flow of the work carried out during the development of the project will study of the most appropriate remeshing algorithms between both codes. In addition explain the selection and implementation of methods to verify internally the correct transmission of the variables involved between both nets. Finally the selection of cases for verification and validation of the interaction between both codes in each of the possible fields of application will be exposed.

  4. El desarrollo de los cibermedios venezolanos

    Directory of Open Access Journals (Sweden)

    Elías Said Hung

    2012-01-01

    Full Text Available En esta investigación se analizan 68 medios digitales en Venezuela, a partir de los resultados obtenidos entre octubre y noviembre de 2010, en el marco del proyecto "Los Cibermedios en Colombia y América Latina", realizado desde la Universidad del Norte, con el apoyo de la Universidad de los Andes (Venezuela, con el fin de determinar el grado de adopción del ciberperiodismo y de las web 2.0 en este país. El estudio parte del modelo de análisis propuesto por Rodríguez-Martínez, Codina y Pedraza-Jiménez (2010. Los resultados apuntan a un bajo desarrollo de los cibermedios en Venezuela y la necesidad de un profundo debate y acciones orientadas al aprovechamiento de las potencialidades de las TIC desde los medios digitales en dicho país.

  5. Desarrollo multiplataforma IOS vs Android con Xamarin

    OpenAIRE

    Esteban Blanco, Alberto

    2017-01-01

    En la última década, la tecnología incorporada a los teléfonos móviles ha provocado una disrupción en el mercado de las telecomunicaciones. Esta tecnología ha convertido a los dispositivos en máquinas muy potentes, a la vez que económicamente asequibles para la mayor parte de la población mundial. Ello ha provocado la aparición de un nuevo mercado en el sector del desarrollo, las aplicaciones móviles. Para el año 2019, se espera alcanzar cinco mil millones de dispositivos activos. Como ver...

  6. Displasia del desarrollo de la cadera

    Directory of Open Access Journals (Sweden)

    F. Ximena Ortega, Dra.

    2013-01-01

    Full Text Available El desarrollo de la cadera comienza in útero y termina con la cadera adulta. Existe consenso en la necesidad de un screening que combine en forma eficiente la evaluación clínica con los estudios de imágenes para conseguir un diagnóstico certero y un tratamiento precoz. Tanto la radiografía como la ecografía permiten la caracterización de la cadera con diferencias técnicas que sustentan sus debilidades y fortalezas. La indicación y oportunidad de estos estudios está condicionada en nuestro medio por nuestra historia de screening universal con radiografía simple. El objetivo de esta revisión es actualizar conceptos en una patología prevalente y cuyo manejo genera controversias.

  7. Annual Report 1995. Direccion de Investigacion y Desarrollo; Informe Anual 1995. Direccion de Investigacion y Desarrollo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    In this report, the main results of the projects, studies, services and departmental activities of the Direccion de Investigacion y Desarrollo of the Instituto Nacional de Investigaciones Nucleares (ININ), during 1995, are shown. It includes the results of different areas such as Nuclear Chemistry and Physics, Environmental Science and Genetics, Radiobiology, Nuclear Technology, Nuclear Fuel and Technical Assistance, as well as their main objectives, stage of development and publications. (Author).

  8. Dosimetric characterization of radionuclides for systemic tumor therapy: Influence of particle range, photon emission, and subcellular distribution

    International Nuclear Information System (INIS)

    Uusijaervi, Helena; Bernhardt, Peter; Ericsson, Thomas; Forssell-Aronsson, Eva

    2006-01-01

    emitters, photon emitters, and alpha emitters. The TND values of the beta emitters were not affected by the subcellular distribution of the radionuclide. The TND values of the Auger electron emitters were affected by the subcellular radionuclide distribution. The photon emitters showed low TND values that were only slightly affected by the subcellular radionuclide distribution. The alpha emitters showed high TND values that were only slightly affected by the subcellular radionuclide distribution. This dosimetric characterization of radionuclides may be valuable in choosing the appropriate radionuclides for specific therapeutic applications

  9. La evaluación del desarrollo

    Directory of Open Access Journals (Sweden)

    Jan J. F. ter Laak

    2013-09-01

    Full Text Available Se sostiene que la psicología del desarrollo es la "tercera disciplina de la psicología científica", enfatizándose el aspecto formal de la continuidad/cambio conductual. Los constructos que elaboran este aspecto son semánticos y no modelos matemáticos vacíos o borrosos conceptos de sentido común. Se describe comprensivamente la evaluación como una matriz de cuatro componentes (teoría de los tests, constructos, tests, proceso diagnóstico por tres niveles (sentido común, constructos científicos, modelos matemáticos. Se confrontan la psicología del desarrollo y la evaluación con la finalidad de captar y ampliar el significado de continuidad/cambio, como en la validación de constructos "convergentes" y "discriminantes". La teoría de los tests, los tests y el proceso diagnóstico ofrecen,  respectivamente, modelos, instrumentos y un programa para evaluar la conducta. It is argued that developmental psychology is the "third discipline of scientific psychology", emphasizing the formal aspect of behavioral continuity/change. Constructs elaborating this aspect are semantical and not empty mathematical models or fuzzy common sense concepts. Assessment is comprehensively described as a matrix of four components (test theory, constructs, tests, diagnostical proces by three levels (common sense, scientific constructs, mathematical models. Developmental psychology and assessment are confronted to conquer and extend the meaning of continuity/change, as in "convergent" and "discriminant" construct validation. Test theory, tests and the diagnostical proces respectively offer models, instruments and a program for assessing behavior.

  10. Reflexiones sobre las estrategias de desarrollo

    Directory of Open Access Journals (Sweden)

    Alberto Ortíz Gómez

    1991-05-01

    Full Text Available RESUMEN La apertura constituye actualmente el tema que mayor atención genera en los diversos círculos donde se debate si la condición  económica de la nación debe descansar en el modelo de sustitución de importaciones, debe residir en el fortalecimiento  de las exportaciones menores o debe definitivamente sustentarse en esfuerzos  integrados del aparato  gubernamental, el sistema financiero y la clase empresarial. Nadie discute la importancia de avanzar en pos de la actualización tecnológica, el incremento de los coeficientes de productividad, el mejoramiento de los niveles de calidad y la consecuente  intromisión de nuestra producción en los mercados internacionales. Frente a la necesidad de eliminar atávicas costumbres relacionadas con el pensar actuar en pequeño, vivir el pasado, aprovechar situaciones monopólicas de mercado y usufructuar el proteccionismo gubernamental, el remezón constitucional y la apertura en todos los órdenes de la vida nacional deben apuntar a un desarrollo de que participe de la colectividad en su conjunto. Sin embargo, en el convencimiento en las ventajas que plantean el nuevo esquema de desarrollo, es claro que existen dudas a espejar  e interrogantes no resueltos sobre la forma como deben articularse las  medidas económicas instauradas alrededor  de un proceso de apertura cuyos resultados no pueden analizarse con el criterio miope de quienes todo lo juzgan con base en la inmediatez.

  11. Contura Multi-Lumen Balloon Breast Brachytherapy Catheter: Comparative Dosimetric Findings of a Phase 4 Trial

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Douglas W., E-mail: darthur@mcvh-vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Vicini, Frank A. [Michigan Healthcare Professionals/21st Century Oncology, Farmington Hills, Michigan (United States); Todor, Dorin A. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Julian, Thomas B. [Allegheny General Hospital, Temple University School of Medicine, Pittsburgh, Pennsylvania (United States); Cuttino, Laurie W.; Mukhopadhyay, Nitai D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States)

    2013-06-01

    Purpose: Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Methods and Materials: Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥95% of the prescribed dose (PD) covering ≥95% of the target volume (TV); maximum skin dose ≤125% of the PD; maximum rib dose ≤145% of the PD; and V150 ≤50 cc and V200 ≤10 cc. Results: Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Conclusions: Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals.

  12. Contura Multi-Lumen Balloon breast brachytherapy catheter: comparative dosimetric findings of a phase 4 trial.

    Science.gov (United States)

    Arthur, Douglas W; Vicini, Frank A; Todor, Dorin A; Julian, Thomas B; Cuttino, Laurie W; Mukhopadhyay, Nitai D

    2013-06-01

    Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥ 95% of the prescribed dose (PD) covering ≥ 95% of the target volume (TV); maximum skin dose ≤ 125% of the PD; maximum rib dose ≤ 145% of the PD; and V150 ≤50 cc and V200 ≤ 10 cc. Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P ≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals. Copyright © 2013 Elsevier Inc. All rights

  13. Environmental vigilance programmes of desalination plants. Development of an evaluations method of its application; Los Programas de Vigilancia Ambiental de las Instalaciones Desalinizadoras de Agua Marina. Desarrollo de un metodo de valoracion de su aplicacion

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Arriaga, S.; Garcia Sanchez-Colomer, M.

    2008-07-01

    This article aims to develop a working methodology to assess the application of the measures designed to avoid, reduce and, if possible, remedy significant adverse effects, included in the Environmental Vigilance Programmes. the study is based on a practical case study of the building project, currently under development, of a desalination plant located in the Spanish Mediterranean coast. A collection of measures was selected to be fulfilled in any building project of a desalination plant, and thus the requirements derivates from them. Their analysis will allow to establish the level of fulfillment (regarding to the measures taken from the Environmental Vigilance Programme or the Declaration of Environmental Impact) and the evaluation (regarding to the measures taken from specialized bibliography) of the indicators implementation. This monitoring provides the supervisor of environmental issues with a valid tool to negotiate with the developer certain modifications, with the objective or improving the effectiveness of the measures described in the Environmental Vigilance Programme. (Author) 5 refs.

  14. CaSO4: Dy + Teflon dosimetric pellets for X, beta and gamma radiation detection

    International Nuclear Information System (INIS)

    Campos, L.L.; Lima, M.F.

    1987-08-01

    CaSO 4 : Dy + TEFLON dosimetric pellets with high sensitivity and low cost for X, beta and gamma radiation monitoring were studied and developed by the Dosimetric Material Production Laboratory of the Radiological Protection Departament and are disposable for sale. The thickness of the pellets are suitable for X, beta and gamma radiation measurements. The dosimetric properties of these pellets were determined and presented in this work. The results show the usefulness of 0,20mm thick pellets for beta radiation monitoring and 0,80mm thick pellets for x and gamma radiation detection. (Author) [pt

  15. Dosimetric comparison between techniques for irradiation of breast plastron

    International Nuclear Information System (INIS)

    Trinca, W.C.; Bruning, F.F.; Caldeira, F A.M.; Silveira, T.B da; Batista, D.V.S.; Andrade, R.R.

    2009-01-01

    Patients with breast cancer undergoing radical mastectomy has as an indication of adjuvancy the irradiation of the breast plastron. This paper makes a comparison between different techniques for treatment of breast plastron routinely used in the National Cancer Institute of Brazil (INCA): The irradiation with tangential fields of photons at 6 MV linear accelerator and irradiation with direct angled fields of electron beams of 6 and 9 MeV. We performed dosimetric comparisons in a tissue-equivalent phantom with the use of radiochromic films for verification of coverage and homogeneity of dose for all technical requirements. Tangential fields in the coverage and homogeneity were satisfactory and well cover the clinical aspects as well as beam 9 MeV, despite a small loss at the edge of the external field. Already in 6 MeV beam, there was significant loss in the end, with significant subdoses of 3 cm in the last field. (author)

  16. Speciation and internal dosimetry: from chemical species to dosimetric models

    International Nuclear Information System (INIS)

    Paquet, F.; Frelon, S.; Cote, G.; Madic, C.

    2004-01-01

    Speciation studies refer to the distribution of species in a particular sample or matrix. These studies are necessary to improve the description, understanding and prediction of trace element kinetics and toxicity. In case of internal contamination with radionuclides, speciation studies could help to improve both the biokinetic and dosimetric models for radionuclides. There are different methods to approach the speciation of radionuclide in a biological system, depending on the degree of accuracy needed and the level of uncertainties accepted. Among them, computer modelling and experimental determination are complementary approaches. This paper describes what is known about speciation of actinides in blood, GI-tract, liver and skeleton and of their consequences in terms of internal dosimetry. The conclusion is that such studies provide very valuable data and should be targeted in the future on some specific tissues and biomolecules. (authors)

  17. A dosimetric study during cardiac angiography in young children

    International Nuclear Information System (INIS)

    Amiel, M.; Clermont, A.; Jocteur-Monrozier, D.; Moroni, J.P.; Brun, P.

    1976-01-01

    A dosimetric study was carried out in collaboration with the SCPRI in 30 infants during cardiac catheterization for a congenital cardiopathy. As far as the doctor is concerned, the results show that the dose received by the right hand of the operator is the only one that is relatively high and notably higher than in the adult; the other results are in agreement with those published in the literature. For the manipulator the doses received are practically negligible. This finding does not agree with those of certain publications in the literature and it emphasizes the importance of the working conditions for these personnel. For infants, the gonadal dose is much higher than in the adult and the magnitude of the dose relative to the dose at the place of entry of the incident beam, taking into account the weight of the infant, certaintly represents a long-term risk, in particular, in patients who must undergo repeated examinations [fr

  18. Radiation hazards in uranium mining. Epidemiological and dosimetric approaches

    International Nuclear Information System (INIS)

    Myers, D.K.; Johnson, J.R.

    1989-01-01

    Potential health hazards resulting from exposure to various sources of radiation associated with uranium mining have been reviewed: 1) epidemiological observations on groups of miners exposed in the past to high concentrations of radon progeny have been interpreted to suggest a lifetime risk of about 3 x 10 -4 lung cancers per WLM; 2) the total risk of serious health effects resulting from exposure of workers to whole body gamma-radiation might be taken to be about 2 x 10 -2 per Sv; and 3) the potential health effects of inhalation of thoron progeny or of radioactive ore dusts can only be estimated from dosimetric calculations. A review of the uncertainties involved in these calculations suggests that ICRP estimates of the potential toxicity of inhaled thoron progeny are as good as those for inhaled radon progeny. However, the potential health hazards from inhaled uranium and thorium ore dusts have probably been overestimated by a factor of 2 to 10-fold

  19. Dosimetric properties of the fast neutron therapy beams at TAMVEC

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.R.; Otte, V.A.

    1975-01-01

    In October 1972, M.D. Anderson Hospital and Tumor Institute of the University of Texas System Cancer Center initiated a clinical trial of fast neutron radiotherapy using the cyclotron at Texas A and M University. Initially, the study used neutrons produced by bombarding beryllium with 16 MeV deuterons, but since March, 1973, neutrons from 50 MeV deuterons have been used. The dosimetric properties of the 30 MeV beams have also been measured for comparison with the neutron beams from D-T generators. The three beams are compared in terms of dose rate, skin sparing, depth dose and field flatness. Isodose curves for treatment planning were generated using the decrement line method and compared to curves measured by a computer controlled isodose plotter. This system was also used to measure the isodose curves for wedge fields. Dosimetry checks on various patients were made using silicon diodes as in vivo fast neutron dosimeters

  20. Dosimetric commissioning of a CBCT system for IGRT purposes

    International Nuclear Information System (INIS)

    Alfonso, R.; Ascencion, Y.; Castillo, D.; Linares, H.; Argota, R.; Garcia, F.

    2015-01-01

    During the last few years the use of tomographic imaging systems based on kilo voltage, cone shaped photon beams (kV-CBCT) for ensuring an accurate positioning of patients in radiotherapy treatments has expanded to low income departments, such as those existing in public health systems of low and middle income countries (LMIC). Although several dosimetric studies have been published so far, showing results of collateral dose in patients exposed to kV-CBCT studies for image guidance radiotherapy purposes (IGRT), their main objective is to demonstrate that these doses are significantly lower than the prescribed dose to the target volume and even the dose to organs and healthy tissues. In the actual study a methodology is proposed to reduce the CBCT dose during IGRT procedures for tumor targets located in the thorax region, where motion management is crucial. Criteria for dose optimization, based on image quality indexes and automated positioning accuracy, were implemented. (Author)

  1. Dosimetric of extremities with Dosemeters thermoluminescent in Cuba

    International Nuclear Information System (INIS)

    Molina Perez, D.; Diaz Bernal, E.; Vera Alonso, L.

    1998-01-01

    From final of the year 1995 in the CPHR implement the service of monitoring of the extremities using Dosemeter thermoluminescent (TL). The dosemeter consists on a metallic ring with a circular hole where a detector of LiF:Mg,Ti is placed (model JR1152C) of 5x5x0.9 mm 3 , covered by a fine layer of polyethylene. In the work the characteristic dosimetric as of the dosemeter is studied it satisfies the main requirements for their use in the monitoring from the exhibition to radiation photonic of the extremities. The doses are also presented registered during the first two years of operation of the service. The results obtained until the moment point out to you practice them of nuclear medicine, radiotherapy and production of substances radioactive how as of more contribution

  2. A biokinetic and dosimetric model for the metabolism of uranium

    International Nuclear Information System (INIS)

    Wrenn, M.E.; Bertelli, L.; Durbin, P.W.; Eckerman, K.F.; Lipsztein, J.L.; Singh, N.P.

    1995-10-01

    Experiments involving injection and inhalation of uranium compounds into several animal species as well as those associated with humans are described and analyzed. A revised biokinetic and dosimetric model for the metabolism of uranium suitable for bioassay procedures is proposed. The model consists of a systematic part coupled to a model of the respiratory tract. The model has been tested against human data which incorporates in vivo measurements over the chest and measurements of urine, feces, and autopsy and biopsy samples.In particular the lung model of the International Commission on Radiological Protection, Publication 30 ( ICRP-30 ), has been modified in order to provide a model which more nearly predicts urinary excretion in accord with the experiences in humans and animals. We have also tested the data against the new ICRP (LUDEP) lung model. (author). 55 refs., 14 tabs., 33 figs

  3. Development of Pre-Industrial Processes for the Preparation of Thin Film Coatings for Energy Applications; Desarrollo de Procesos Pre-Industriales para la Preparacion de Recubrimientos en Pelicula Delgada para Aplicaciones Energeticas

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, C.; Guillen, C.; Gutierrez, M.T.

    2005-07-01

    Indium sulfide (In2S3) is an interesting candidate as buffer layer in heterojunction solar cells based on a Cu(In,Ga)Se2 absorbent layer. Modulated Flux Deposition (MFD) is a physical evaporation-type synthesis technique, specific for thin film synthesis, in which the substrate is exposed to the deposition of each element and heating in a sequential and cyclic way. This vacuum process allows a fine adjustment of the elemental vapor fluxes. In2S3 polycrystalline thin films were deposited on glass substrates by MFD. The influence of different deposition parameters (substrate temperature, both evaporation source temperatures, substrate angular velocity) on the composition, structure and optical properties were studied. All the obtained samples consisted in tetragonal Beta-In2S3 with high or total (103) preferential orientation. Quite thin layers (50-100 nm thick) have been achieved, with smoothed small grained microstructures. Respect to the sulfur supply, its reduction improved the crystallinity and decreased very slightly the bandgap energy. As conclusion, thin films with morphological and optical properties adequate to the mentioned application were archived decreasing the substrate temperature up to 310 C. (Author) 42 refs.

  4. Development of a methodology for the economical analysis of fuel cycles, application to the Laguna Verde central; Desarrollo de una metodologia para el analisis economico de ciclos de combustible, aplicacion a la Central Laguna Verde

    Energy Technology Data Exchange (ETDEWEB)

    Malfavon, S.M.; Trejo, M.G.; Hernandez, H. [FI-UNAM, 04500 Mexico D.F. (Mexico); Francois, J.L.; Ortega, R.F. [FI-UNAM, Paseo Cuauhnahuac 8532, Jiutepec, Morelos (Mexico)

    2003-07-01

    In this work a methodology developed to carry out the economical analysis of the fuel cycle of a nuclear reactor is presented. The methodology was applied to the Laguna Verde Nuclear Power Station (CNLV). The design of the reload scenarios of the CNLV are made with the Core Master Presto code (CM-Presto), three-dimensional simulator of the reactor core, the launched data by this, as well as the information of the Energy use plan (PUE), it allowed us to obtain reliable results through the fitness of an algorithm of economic calculation that considers all the components of the fuel cycle to present worth. With the application of the methodology it was obtained the generated energy, as well as their respective cost of each sub lot type of assemblies by operation cycle, from the start-up of the CNLV until September 13, 2002. Using the present worth method its were moved all the values at November 5, 1988, date of operation beginning. To the final of the analysis an even cost of 6.188 mills/kWh was obtained for those first 9 cycles of the Unit 1 of the CNLV, being observed that the costs of those first 3 operation cycles are the more elevated. Considering only the values starting from the cycle 4, the levelled cost turns out to be of 5.96 mills/kWh. It was also obtained the cost by fuel lot to evaluate the performance of assemble with the same physical composition. (Author)

  5. Beam standardization and dosimetric methodology in computed tomography

    International Nuclear Information System (INIS)

    Maia, Ana Figueiredo

    2005-01-01

    Special ionization chambers, named pencil ionization chambers, are used in dosimetric procedures in computed tomography beams (CT). In this work, an extensive study about pencil ionization chambers was performed, as a contribution to the accuracy of the dosimetric procedures in CT beams. The international scientific community has recently been discussing the need of the establishment of a specific calibration procedure for CT ionization chambers, once these chambers present special characteristics that differentiate them from other ionization chambers used in diagnostic radiology beams. In this work, an adequate calibration procedure for pencil ionization chambers was established at the Calibration Laboratory, of the Institute de Pesquisas Energeticas e Nucleares, in accordance with the most recent international recommendations. Two calibration methodologies were tested and analyzed by comparative studies. Moreover, a new extended length parallel plate ionization chamber, with a transversal section very similar to pencil ionization chambers, was developed. The operational characteristics of this chamber were determined and the results obtained showed that its behaviour is adequate as a reference system in CT standard beams. Two other studies were performed during this work, both using CT ionization chambers. The first study was about the performance of a pencil ionization chamber in standard radiation beams of several types and energies, and the results showed that this chamber presents satisfactory behaviour in other radiation qualities as of diagnostic radiology, mammography and radiotherapy. In the second study, a tandem system for verification of hal'-value layer variations in CT equipment, using a pencil ionization chamber, was developed. Because of the X rays tube rotation, the determination of half-value layers in computed tomography equipment is not an easy task, and it is usually not performed within quality control programs. (author)

  6. EPR dosimetric properties of nano-barium sulfate

    International Nuclear Information System (INIS)

    Aboelezz, E.; Hassan, G.M.; Sharaf, M.A.; El-Khodary, A.

    2015-01-01

    Nano/micro BaSO 4 were prepared through the co-precipitation method to measure ionizing radiation doses using electron paramagnetic resonance (EPR). The nano-BaSO 4 sample was characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The dose response and fading properties of nano- and micro-phase BaSO 4 were compared in EPR spectra. The prepared nano- and micro-BaSO 4 samples have the same hole and electron centers, which may be attributed to SO 4 − and SO 3 − , respectively. The dosimetric signals for prepared nano- and micro-BaSO 4 have spectroscopic splitting factor (g) with values 2.0025±0.0006 and 2.0027±0.0006, respectively. The nanocrystalline sample has a linear γ-ray dose response over the range 0.4 Gy–1 kGy. The performance parameters which including detection limit and critical level calculated from weighted and unweighted least-squares fitting. The sensitivity of nano-BaSO 4 to γ-ray is one and a half times more than alanine. The lifetime and activation energy for nano-BaSO 4 were estimated by conducting a thermal stability study, and were 5.7±1.1×10 4 years and 0.73±0.14 eV, respectively. The combined and expanded uncertainties accompanying measurements were ±3.89% and ±7.78%, respectively. - Highlights: • Preparation of nano-BaSO 4 using the co-precipitation method. • Study of the dosimetric properties of nano-barium sulfate using the EPR technique. • Comparison between a new EPR dosimeter using nano-materials and standard alanine. • Calculation of the uncertainty budget for nano-BaSO 4

  7. Effect of blood activity on dosimetric calculations for radiopharmaceuticals

    Science.gov (United States)

    Zvereva, Alexandra; Petoussi-Henss, Nina; Li, Wei Bo; Schlattl, Helmut; Oeh, Uwe; Zankl, Maria; Graner, Frank Philipp; Hoeschen, Christoph; Nekolla, Stephan G.; Parodi, Katia; Schwaiger, Markus

    2016-11-01

    dosimetric calculations. Hence, blood samples should be included in all pharmacokinetic and dosimetric studies for new tracers if possible.

  8. Dosimetric Analysis of Respiratory-Gated Radiotherapy for Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Xi Mian; Zhang Li; Liu Mengzhong; Deng Xiaowu; Huang Xiaoyan; Liu Hui

    2011-01-01

    The purpose of this study was to define individualized internal target volume (ITV) for hepatocellular carcinoma (HCC) using 4D computed tomography (4DCT), and to determine the geometric and dosimetric benefits of respiratory gating. Gross tumor volumes (GTVs) were contoured on 10 respiratory phases of 4DCT images for 12 patients with HCC. Three treatment plans were prepared using different planning target volumes (PTVs): (1) PTV 3D , derived from a single helical clinical target volume (CTV) plus conventional margins; (2) PTV 10phases , derived from ITV 10phases , which encompassed all 10 CTVs plus an isotropic margin of 0.8 cm; (3) PTV gating , derived from ITV gating , which encompassed three CTVs within gating-window at end-expiration plus an isotropic margin of 0.8 cm. The PTV 3D was the largest volume for all patients. The ITV-based plans and gating plans spared more normal tissues than 3D plans, especially the liver. Without increasing normal tissue complication probability of the 3D plans, the ITV-based plans allowed for increasing the calculated dose from 50.8 Gy to 54.7 Gy on average, and the gating plans could further escalate the dose to 58.5 Gy. Compared with ITV-based plans, the dosimetric gains with gating plan strongly correlated with GTV mobility in the craniocaudal direction. The ITV-based plans can ensure target coverage with less irradiation of normal tissues compared with 3D plans. Respiratory-gated radiotherapy can further reduce the target volumes to spare more surrounding tissues and allow dose escalation, especially for patients with tumor mobility >1 cm.

  9. Development and application of a third order scheme of finite differences centered in mesh; Desarrollo y aplicacion de un esquema de tercer orden de diferencias finitas centradas en malla

    Energy Technology Data Exchange (ETDEWEB)

    Delfin L, A.; Alonso V, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Valle G, E. del [IPN-ESFM, 07738 Mexico D.F. (Mexico)]. e-mail: adl@nuclear.inin.mx

    2003-07-01

    In this work the development of a third order scheme of finite differences centered in mesh is presented and it is applied in the numerical solution of those diffusion equations in multi groups in stationary state and X Y geometry. Originally this scheme was developed by Hennart and del Valle for the monoenergetic diffusion equation with a well-known source and they show that the one scheme is of third order when comparing the numerical solution with the analytical solution of a model problem using several mesh refinements and boundary conditions. The scheme by them developed it also introduces the application of numeric quadratures to evaluate the rigidity matrices and of mass that its appear when making use of the finite elements method of Galerkin. One of the used quadratures is the open quadrature of 4 points, no-standard, of Newton-Cotes to evaluate in approximate form the elements of the rigidity matrices. The other quadrature is that of 3 points of Radau that it is used to evaluate the elements of all the mass matrices. One of the objectives of these quadratures are to eliminate the couplings among the Legendre moments 0 and 1 associated to the left and right faces as those associated to the inferior and superior faces of each cell of the discretization. The other objective is to satisfy the particles balance in weighed form in each cell. In this work it expands such development to multiplicative means considering several energy groups. There are described diverse details inherent to the technique, particularly those that refer to the simplification of the algebraic systems that appear due to the space discretization. Numerical results for several test problems are presented and are compared with those obtained with other nodal techniques. (Author)

  10. La evaluación y el desarrollo del aprendizaje

    OpenAIRE

    Arco Juan, Francisco Javier del

    2011-01-01

    El objetivo del presente trabajo es abordar el proceso de desarrollo de las competencias y de las cualidades del emprendedor. Para conseguir ambos fines se familiariza al alumno con las herramientas necesarias para el desarrollo del emprendizaje, siendo el Plan de Negocio el elemento clave de reflexión y desarrollo. Se considerarán y valorarán, además, las competencias básicas del emprendedor, como el trabajo en equipo, el liderazgo y la toma de decisiones. No data (2011) ...

  11. Medio ambiente y desarrollo: su implicancia nacional e internacional

    OpenAIRE

    Martínez Lestard, Pablo

    1992-01-01

    Cuando el Presidente de la Comisión Mundial sobre el Medio Ambiente y el Desarrollo, el Sr. Gro Harlem Brundtland, Primer Ministro de Noruega, presentó el reporte "Nuestro Futuro Común" a la Asamblea General de la ONU en 1987, fue el momento en que se dio a conocer, ante el foro mundial, la idea del "desarrollo sostenible". Según Lloyd Timberlake, editor principal en el Instituto Internacional para el Medio Ambiente y el Desarrollo (Londres), el reporte "extremista" únicamente en cu...

  12. Más alla del concepto: desarrollo sostenible

    OpenAIRE

    Benavides López, Laura

    2013-01-01

    El artículo tiene la finalidad de promover la reflexión con respecto al desarrollo sostenible, como un marco de referencia para el educador, que le permita comprender la Década de la Educación para el Desarrollo Sostenible y la Declaratoria Paz con Naturaleza.  La autora describe y reflexiona sobre el concepto, desde una perspectiva basada en la alteridad; por lo tanto, parte de una posición ética donde se potencializa a la persona para que sea constructora del desarrollo sostenible que requi...

  13. Desarrollo vocacional y política pública

    OpenAIRE

    Watts, Anthony G.

    2000-01-01

    El trabajo analiza la base para el interés político en los servicios de desarrollo vocacional, y la manera en la cual esta base está siendo fortalecida por las actuales transformaciones en el trabajo y en el desarrollo vocacional. Se exploran los papeles potenciales de la política pública en los servicios de desarrollo vocacional así como las formas en las que dichos servicios pueden influenciar el proceso de la creación de políticas. Se identifican una gama de temas de política relacionados ...

  14. Desarrollo sustentable: ¿todavía esperando a Godot?

    OpenAIRE

    Guimarães, Roberto P.

    2015-01-01

    El artículo hace un recorrido crítico por la evolución del concepto de sostenibilidad y su aplicación en la práctica. Las condiciones internacionales de desarrollo no favorecen un crecimiento sostenible, sin embargo, cuando es el ser humano quien constituye el centro dela acción pública es posible un nuevo estilo de desarrollo sostenible desde el punto de vista ambiental, social, cultural y político. En este sentido, el autor señala que es necesaria una nueva ética de desarrollo, en la que lo...

  15. EL AMBIENTE Y EL DESARROLLO SUSTENTABLE EN LA CIUDAD LATINOAMERICANA

    OpenAIRE

    Luis Alfonso Sandia Rondón

    2009-01-01

    El Desarrollo Sustentable constituye el paradigma actual dominante para orientar el desarrollo económico y social de la humanidad. A pesar del aparente acuerdo global acerca de su importancia, su aplicación práctica es de difícil instrumentación, especialmente en el medio urbano latinoamericano, donde son múltiples las brechas que separan la ciudad actual de la deseada ciudad sustentable. Algunos aspectos para el análisis de la ciudad, el ambiente y el desarrollo sustentable son discutidos en...

  16. Calidad en el desarrollo de Sistemas de Software

    OpenAIRE

    Pesado, Patricia Mabel; Bertone, Rodolfo Alfredo; Ramón, Hugo Dionisio; Pasini, Ariel C.; Esponda, Silvia; Alonso, Laura Mabel

    2006-01-01

    El proyecto de investigación y desarrollo “Sistemas de Software Distribuidos. Aplicaciones en procesos industriales, E-government y E-learning” abarca aspectos que van desde los fundamentos del desarrollo (Técnicas de Ingeniería de requerimientos, Metodologías de Gestión y Desarrollo de Proyectos, Técnicas de Planificación, Métricas, Normas de Calidad, Web-Systems) hasta la concepción de aplicaciones específicas orientadas a los procesos industriales (sistemas de planeamiento industrial, cont...

  17. Plan de desarrollo del CBD de Melbourne, Australia

    OpenAIRE

    MAICAS BELTRÁN, TOMÁS

    2015-01-01

    El proyecto se desarrolla en una parcela del CBD (Central Business District) de Melbourne. Se plantea como objetivo la planificación urbana y la repoblación del CBD, y se consideran una serie de aspectos relacionados con el desarrollo sostenible. El programa incluye el desarrollo de zonas verdes, edificación vertical, espacios comerciales, culturales y de ocio, oficinas, hoteles y zona residencial. El desarrollo del proyecto comienza con la creación de las calles. Tras crear la edificación qu...

  18. La ayuda oficial al desarrollo en el sector agrario

    OpenAIRE

    Areta García, Álvaro; Marín, Gonzalo

    2006-01-01

    El primer Objetivo de Desarrollo del Milenio habla de erradicar la pobreza extrema y el hambre. Por tanto, dado que la mayoría de la gente pobre vive en el medio rural o depende de la agricultura, y que en las naciones más pobres la agricultura prepara el terreno para el desarrollo económico, será imprescindible una gran inversión en el desarrollo rural y, por ende, en uno de sus “pilares” básicos, la agricultura. Sin embargo, el papel de la agricultura en el marco de la Ayuda Oficial al Desa...

  19. A dosimetric comparison of IORT techniques in limited-stage breast cancer

    International Nuclear Information System (INIS)

    Nairz, O.; Deutschmann, H.; Kopp, M.; Wurstbauer, K.; Kametriser, G.; Fastner, G.; Merz, F.; Sedlmayer, F.; Reitsamer, R.; Menzel, C.

    2006-01-01

    Background and purpose: for intraoperative radiotherapy (IORT) during breast-conserving treatment four different techniques have been addressed: interstitial brachytherapy, an inflatable balloon with a central high-dose-rate source (MammoSite), a miniature orthovolt system (Intrabeam), and linac-based electron radiotherapy (IOERT). The dosimetric properties of these methods are compared. Material and methods: planning target volumes (PTVs) of the same size but of different shapes are assumed, corresponding to the technique's specific situs. Dose distributions for the PTVs and for surrounding tissues are demonstrated by dose-volume histograms and a list of physical parameters. A dose inhomogeneity index (DII) is introduced to describe the deviation of a delivered from the prescribed dose, reaching its minimal value 0 in case of perfect homogeneity. Results: in terms of DII, IOERT reaches the lowest value followed by the MammoSite, the Intrabeam and interstitial implants. The surrounding tissues receive the smallest average dose with IOERT, closely followed by the orthovolt system. Conclusion: when comparing simplified geometric figures, IOERT delivers the most homogeneous dose distributions. However, in clinical reality PTVs often present asymmetric shapes instead of ideal geometries. Due to a strictly centric dose fall-off, any system with a round central applicator will have technical limits. During IOERT margin-directed applicator guidance is possible and interstitial brachytherapy allows for polygonal dose shaping. These techniques seem to be superior for asymmetric PTV irradiation. (orig.)

  20. Comparison and utilization of two dosimetric systems for e-beam industrial irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fortes, Marcio Z., E-mail: mzamboti@aceletron.com.b [Aceletron Irradiacao Industrial, Rio de Janeiro, RJ (Brazil). Gerencia Tecnica e Operacoes; Sousa, Fernando N.C. de; Boente, Otavio C., E-mail: fernando.nuno@aceletron.com.b, E-mail: otavio@aceletron.com.b [Aceletron Irradiacao Industrial, Rio de Janeiro, RJ (Brazil). Gerencia de Desenvolvimento de Produtos; Sousa, Nuno R.A., E-mail: engenheiro.nuno.sousa@gmail.co [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Engenharia Mecanica

    2009-07-01

    The utilization of electron linear accelerators (LINAC's) for industrial irradiation of several products like turf, sterilization of medical products, cosmetics, polymers, food, and gems, can only be successful if a reliable dosimetric system is chosen. There are several different available technologies and two were selected for this study. The first one uses alanine dosimeters which can be read with electron spin resonance spectrometers (ESR); the second uses B3 radiochromic dosimeters which are read with a spectrophotometer. This study presents a comparison of both technologies in the dose range of 1 to 80 kGy, taking into account initial cost, precision, reading time, calibration, among others, for a typical 24 hour production run, and for normal operational routines and tests. It is shown that each system has its own advantages and disadvantages, and that both can be used in an e-beam installation. However, for industrial applications it is necessary to optimize the process, so it is presented which dosimeter is used for each routine application. (author)

  1. Dosimetric Significance of the ICRP's Updated Guidance and Models, 1989-2003, and Implications for U.S. Federal Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.

    2003-09-10

    Over the past two decades the U.S. Environmental Protection Agency (EPA) has issued a series of Federal guidance documents for the purpose of providing the Federal and State agencies with technical information to assist their implementation of radiation protection programs. Currently recommended dose conversion factors, annual limits on intake, and derived air concentrations for intake of radionuclides are tabulated in Federal Guidance Report No. 11 (FGR 11), published in 1988. The tabulations in FGR 11 were based on dosimetric quantities and biokinetic and dosimetric models of the International Commission on Radiological Protection (ICRP) developed for application to occupational exposures. Since the publication of FGR 11 the ICRP has revised some of its dosimetric quantities and its models for workers and has also developed age-specific models and dose conversion factors for intake of radionuclides by members of the public. This report examines the extent of the changes in the inhalation and ingestion dose coefficients of FGR 11 implied by the updated recommendations of the ICRP, both for workers and members of the public.

  2. Determination of trapping parameters of dosimetric thermoluminescent glow peak of lithium triborate (LiB{sub 3}O{sub 5}) activated by aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kafadar, V. Emir [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yazici, A. Necmeddin, E-mail: yazici@gantep.edu.t [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey); Yildirim, R. Gueler [University of Gaziantep, Department of Engineering Physics, 27310 Gaziantep (Turkey)

    2009-07-15

    Lithium triborate (LBO) is a newly developed ideal nonlinear optical (NLO) crystal used in laser weapon, welder, radar, tracker, surgery, communication, etc. The effective atomic number (Z{sub eff}=7.3) makes it a tissue equivalent material and this encourages studies on its thermoluminescence (TL) properties for a radiation dosimetry. The previous studies have shown that Al-doped LiB{sub 3}O{sub 5} is a promising thermoluminescent dosimetric (TLD) material for dosimetric purposes and continuous and systematic investigations to improve its quality to get ones suited for dosimeter applications are worthy. In the given study, the additive dose (AD), initial rise with partial cleaning (IR), variable heating rate (VHR), peak shape (PS), three-points method (TPM) and computerized glow deconvolution (CGCD) methods were used to determine the kinetic parameters, namely the order of kinetics (b), activation energy (E{sub a}) and the frequency factor (s) associated with the dosimetric thermoluminescent glow peak (P3) of Al-doped LiB{sub 3}O{sub 5} after different dose levels with beta-irradiation.

  3. Application of coal combustion residues to the stabilization/solidification of industrial wastes (IRIS); Desarrollo de un Proceso, a Escala Piloto de Inertizacion de Residuos Industriales con Cenizas Volantes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    Stabilization/solidification (S/S) processes, also called inertization processes, are a group of techniques which employ additives to reduce the mobility of the hazardous components from the waste and make possible for the residue to be accepted for its disposal in a safe way. These processes, mainly applied to wastes that contain heavy metals (such as lead, zinc, cadminum, mercury, copper, nickel, titanium, chromium-III, chromium-VI, arsenic,....) change the waste into a solid-like material in which the metals are trapped (nets and matrix) by physical or chemical links. The IRIS Project, carried out by AICIA through the ECSC Coal Programme with the participation of two industrial partners (Sevillana de Electricidad and EGMASA, a public-owned company for waste treatment), has developed, at pilot scale, a new S/S process for inorganic industrial wastes that uses great quantities of fly ash in the place of other more commonly used and expansive reagents. A pilot plant for 200 kg/h has been designed, built and operated. This facility has allowed to add improvements and scientific foundations to existing S/S technology. It has also allowed to obtain industrial scale parameters for fixed and portable plants. Experiencie have been mainly carried out using fly ash from high quality coals, but types of ash have been tested coming from coals with a greater calcium content, from fluidised bed combustion boilers and from desulphurisation processes, giving very suitable characteristics for their application to S/S processes. The addition of fly ash (up to 30%) in the IRIS process improves the results in comparison with the S/S processes that use only cement, because the final pH obtained (8-11) does not allow amphoteric metallic ions to escape in the leachate. The same as other S/S processes, IRIS can be applied also to wastes that contain certain metals (chromium-VI, arsenic, for example) with specific pre-treatments (redox, for example). The efficiency of the IRIS treatment

  4. Development and application of the capacity to make tests of dynamic displacement in samples of oil well drilling cores; Desarrollo y aplicacion de la capacidad para realizar pruebas de desplazamiento dinamico en muestras de nucleos de perforacion de pozos petroleros

    Energy Technology Data Exchange (ETDEWEB)

    Contreras L, Enrique; Garcia M, Pablo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    In the Laboratory of Deposits of the Gerencia de Geotermia of the Instituto de Investigaciones Electricas (IIE) the capacity has been developed to make tests of dynamic oil displacement by means of gas or brine injection in samples of oil well drilling cores. Also the methodologies to interpret the results of these tests in terms of dynamics and the efficiency of the oil recovery in terms of the relative permeability have been developed. These capacities represent a very important contribution towards the improvement of the insufficiency that exists in the country to make the large amount of tests of dynamic displacement that demand the different Actives of PEMEX Exploration and Production (PEP), since they satisfy their necessities of data on which the activities of design and implementation of the most suitable techniques for the hydrocarbon recovery of the oil deposits lean. In the present work these capacities are described and some examples are presented of the results that have been obtained from their application in special studies of drilling cores, which have been recently made in the Laboratory of Deposits of the IIE for diverse Actives of PEP exploitation. [Spanish] En el laboratorio de yacimientos de la Gerencia de Geotermia del Instituto de Investigaciones Electricas (IIE) se ha desarrollado la capacidad de realizar pruebas de desplazamiento dinamico de aceite mediante inyeccion de salmuera o de gases en muestras de nucleos de perforacion de pozos petroleros. Tambien se han desarrollado las metodologias para interpretar los resultados de estas pruebas en terminos de la dinamica y la eficiencia de la recuperacion de aceite y en terminos de la permeabilidades relativas. Estas capacidades representan una contribucion muy importante hacia el mejoramiento de la insuficiencia que existe en el pais para realizar la gran cantidad de pruebas de desplazamiento dinamico que demandan los diferentes activos de explotacion de PEMEX Exploracion y Produccion (PEP), ya

  5. Adaptation of the present concept of dosimetric radiation protection quantities for external radiation to radiation protection practice

    International Nuclear Information System (INIS)

    Boehm, J.; Thompson, I. M. G.

    2004-01-01

    The present concept of dosimetric radiation protection quantities for external radiation is reviewed. For everyday application of the concept some adaptations are recommended. The check of the compliance with dose limits should be performed either by the comparison with values of the respective operational quantities directly or by the calculation of the protection quantity by means of the operational quantity, the appertaining conversion coefficient and additional information of the radiation field. Only four operational quantities are regarded to be sufficient for most applications in radiation protection practice. The term equivalent should be used in the connection dose equivalent only. Proposals are made for names of frequently used operational quantities which are denoted up to now by symbols only. (authors)

  6. LA PRUEBA DE APTITUD ACADÉMICA DE LA UNIVERSIDAD DE COSTA RICA PARA APLICANTES CON NECESIDADES ESPECIALES: NUEVOS DESARROLLOS (THE ACADEMIC APTITUDE TEST UNIVERSITY OF COSTA RICA FOR APPLICANTS WITH SPECIAL NEEDS: NEW DEVELOPMENTS

    Directory of Open Access Journals (Sweden)

    Mainieri Hidalgo Aida María

    2011-08-01

    UCR," developed by the IIP, the CP-PAA. It focuses on theoretical, methodological, technical and practical that have underpinned their design, implementation, use and evaluation, from its beginnings to the present. It refers, specifically, the actions of the UCR about the adequacy of the PAA in response to applicants with special needs. We performed a literature review and documentary, using open interviews after their builders, designers and experts, this basically theoretical and methodological principles of interpretation and hermeneutics. The trajectory is based on different regulations that have global, regional, national and institutional levels also in response to the demands of accessibility conditions and equal opportunities which are based on the principle of equity, this together with that of academic excellence, governing the test since its inception. It identifies four key moments in the process of incorporating the care of special needs and implementing appropriate access in the PAA: Early Integration of Disabled People, 1970-80; first efforts to provide care for ENEE, 1980 - 90; Restructuring in an accessible ENEE University, 1990-2000; and Accessibility in the PAA and Integration Unified Admission to public higher education from 2000 to date. It also asserts the progressive inclusion of ENEE and its scope, with the support of meaningful data.

  7. Practical realisation of individual dosimetric control of internal and external irradiation during works at 'Ukrytie' shelter

    International Nuclear Information System (INIS)

    Likhtarev, I.A.; Bondarenko, O.S.; Berkovskij, V.B.; Chumak, V.K.; Korneev, A.A.; Dmitrienko, A.V.

    1999-01-01

    Individual dosimetric control requires the minimisation of personnel irradiation doses and needs forecasting and planning of dose loads. System of individual dose control and its functions at 'Ukrytie' shelter are described

  8. TEORÍAS DE DESARROLLO ECONÓMICO Y SOCIAL: ARTICULACIÓN CON EL PLANTEAMIENTO DE DESARROLLO HUMANO

    Directory of Open Access Journals (Sweden)

    Giovanni Reyes

    2009-01-01

    Full Text Available El propósito fundamental de este trabajo es discutir las principales teorías del desarrollo económico y social, y articular las mismas a los conceptos fundamentales de desarrollo humano. Para este último postulado conceptual se utilizan básicamente criterios del paradigma de Naciones Unidas, que sirven de base para la elaboración tanto del Informe de Desarrollo Humano Mundial, como de los informes regionales y nacionales, en el ámbito de cada país.

  9. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2011-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. Methods: The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core TM 2 Duo CPU 1.67 GHz processor with 3 Gib RAM. Conclusions: IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  10. Dosimetric study for characterization of a postal system of quality control in brachytherapy

    International Nuclear Information System (INIS)

    Alves, Victor Gabriel Leandro; Queiroz Filho, Pedro Pacheco de; Santos, Denison de Souza; Begalli, Marcia

    2009-01-01

    This work presents a dosimetric study of a postal system, to be developed for measurements of brachytherapy. It was projected a PMMA phantom with orifices for insertion of the high dose 192 Ir source and the T L dosemeters. The system was characterized with using of Monte Carlo simulations, using the dosimetric magnitudes defined at the T G-43 of AAPM, as function of radial dose g(f)

  11. EL AMBIENTE Y EL DESARROLLO SUSTENTABLE EN LA CIUDAD LATINOAMERICANA

    Directory of Open Access Journals (Sweden)

    Luis Alfonso Sandia Rondón

    2009-01-01

    Full Text Available El Desarrollo Sustentable constituye el paradigma actual dominante para orientar el desarrollo económico y social de la humanidad. A pesar del aparente acuerdo global acerca de su importancia, su aplicación práctica es de difícil instrumentación, especialmente en el medio urbano latinoamericano, donde son múltiples las brechas que separan la ciudad actual de la deseada ciudad sustentable. Algunos aspectos para el análisis de la ciudad, el ambiente y el desarrollo sustentable son discutidos en este artículo, en un intento por contribuir con la comprensión de la realidad urbana de la ciudad latinoamericana y las posibilidades de alcanzar su desarrollo sustentable.

  12. Improvements in critical dosimetric endpoints using the Contura multilumen balloon breast brachytherapy catheter to deliver accelerated partial breast irradiation: preliminary dosimetric findings of a phase iv trial.

    Science.gov (United States)

    Arthur, Douglas W; Vicini, Frank A; Todor, Dorin A; Julian, Thomas B; Lyden, Maureen R

    2011-01-01

    Dosimetric findings in patients treated with the Contura multilumen balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) on a multi-institutional Phase IV registry trial are presented. Computed tomography-based three-dimensional planning with dose optimization was performed. For the trial, new ideal dosimetric goals included (1) ≥95% of the prescribed dose (PD) covering ≥90% of the target volume, (2) a maximum skin dose ≤125% of the PD, (3) maximum rib dose ≤145% of the PD, and (4) the V150 ≤50 cc and V200 ≤10 cc. The ability to concurrently achieve these dosimetric goals using the Contura MLB was analyzed. 144 cases were available for review. Using the MLB, all dosimetric criteria were met in 76% of cases. Evaluating dosimetric criteria individually, 92% and 89% of cases met skin and rib dose criteria, respectively. In 93% of cases, ideal target volume coverage goals were met, and in 99%, dose homogeneity criteria (V150 and V200) were satisfied. When skin thickness was ≥5 mm to <7 mm, the median skin dose was limited to 120.1% of the PD, and when skin thickness was <5 mm, the median skin dose was 124.2%. When rib distance was <5 mm, median rib dose was reduced to 136.5% of the PD. When skin thickness was <7 mm and distance to rib was <5 mm, median skin and rib doses were jointly limited to 120.6% and 142.1% of the PD, respectively. The Contura MLB catheter provided the means of achieving the imposed higher standard of dosimetric goals in the majority of clinical scenarios encountered. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Proyecto de desarrollo de una base de datos

    OpenAIRE

    Boshoff de Jong, Etienne

    2013-01-01

    Desarrollo de las fases de planificación, análisis, diseño e implementación de un proyecto de desarrollo de una base de datos para un cliente ficticio. Desenvolupament de les fases de planificació, anàlisi, disseny i implementació d'un projecte de desenvolupament d'una base de dades per a un client fictici. Bachelor thesis for the Computer Science program on Databases.

  14. Desarrollo de software para enseñar

    OpenAIRE

    Pimentel Cintra, Jorge; Medeiros Filho, Dante Alves

    1999-01-01

    La utilización de softwares educativos está siendo muy explorada no proceso de enseñanza y aprendizaje. Los estudios para su desarrollo son así necesarios. El objetivo de este trabajo es analizar los factores que involucran el desarrollo de software educativo, mostrando los componentes que integran su producción, relaciones y formas de evaluación.

  15. Desarrollo y aplicación del diagnóstico y pronóstico técnico al mantenimiento de los sistemas centralizados de aire acondicionado // Develop and application of the diagnosis and technical prediction to the maintenance of the centralized systems of conditi

    Directory of Open Access Journals (Sweden)

    J. L. Sánchez Ávila

    2000-10-01

    Full Text Available Se expone la aplicación del mantenimiento por diagnóstico y pronóstico técnico al sistema centralizado de aireacondicionado con recuperación del calor del hotel LTI Bella Costa; como solución a los graves problemas a que seenfrenta la dirección de servicios técnicos de las instalaciones turísticas para realizar un mantenimiento con calidad y a unmenor costo.El desarrollo de un plan experimental, en las instalaciones del hotel, permitió obtener las curvas que expresan elcomportamiento de la degradación de estos sistemas en el tiempo, así como determinar el momento más oportuno para larealización del mantenimiento.La aplicación de esta investigación permitió la implementación de un mantenimiento menos costoso y de más calidad,aumentando la rentabilidad de la labor del mantenimiento, y lo que es decisivo en este tipo de instalación: la seguridad en laexplotación como garantía de un servicio sin fallas.Palabras claves: mantenimiento, refrigeración, predictivo, diagnóstico, pronóstico.____________________________________________________________________Abstract:In this paper is exposed the application of the maintenance by diagnosis and technical prediction to the centralized systemof air conditioned with heat recovery of the hotel Beautiful LTI Costa; as a solution to the serious problems that thetechnical management services faces in the tourist facilities to carry out a maintenance with quality and whith smaller cost.The development of an experimental plan, in the hotel facilities, allowed to obtain the curves that express the behavior ofthe degradation of these systems in the time, as well as to determine the most opportune moment for the realization of themaintenance.The application of this investigation allowed the implementation of a less expensive maintenance and of more quality,increasing the profitability of the maintenance work, and what is decisive in this installation type: the security in theexploitation as a

  16. Desarrollo y aplicación del diagnóstico y pronóstico técnico al mantenimiento de los sistemas centralizados de aire acondicionado. // Develop and application of diagnosis and technical prediction to maintenance of centralized air conditioned systems.

    Directory of Open Access Journals (Sweden)

    J. L. Sánchez Ávila

    2001-10-01

    Full Text Available Se expone la aplicación del mantenimiento por diagnóstico y pronóstico técnico al sistema centralizado de aireacondicionado con recuperación del calor del hotel LTI Bella Costa; como solución a los graves problemas a que seenfrenta la dirección de servicios técnicos de las instalaciones turísticas para realizar un mantenimiento con calidad y a unmenor costo. El desarrollo de un plan experimental, en las instalaciones del hotel, permitió obtener las curvas que expresanel comportamiento de la degradación de estos sistemas en el tiempo, así como determinar el momento más oportuno para larealización del mantenimiento.La aplicación de esta investigación permitió la implementación de un mantenimiento menoscostoso y de más calidad, aumentando la rentabilidad de la labor del mantenimiento, y lo que es decisivo en este tipo deinstalación: la seguridad en la explotación como garantía de un servicio sin fallas.Palabras claves: Mantenimiento, refrigeración, predictivo, diagnóstico, pronóstico.___________________________________________________________________Abstract:The application of maintenance by diagnosis and technical prediction to centralized system of conditioned air withrecovery of heat is exposed; as solution to the serious problems faces technical services of tourist facilities to carry outmaintenance with quality and smaller cost. The development of an experimental plan, in hotel facilities, allowed to obtaincurves that express the behavior of degradation of these systems in time, as well as to determine the most opportunemoment for the maintenance realization. Application of this investigation allowed the implementation of a less expensivemaintenance with more quality, increasing the profitability of maintenance work, and what is decisive in this type ofinstallation,: the security in the exploitation like guarantee of a service without flaws.Key words. Maintenance, refrigeration, prediction, diagnosis, air conditioned.

  17. Crecimiento vs sosteniblidad: la paradoja del desarrollo

    Directory of Open Access Journals (Sweden)

    Julián Santiago Vásquez Roldán

    2014-12-01

    Full Text Available El desarrollo desde la perspectiva económica le ha asignado al crecimiento de la producción y por ende a la utilización intensiva de los factores productivos la responsabilidad de convertirse en el principal indicador de “bienestar social” sin llegar a considerar el progresivo deterioro ambiental y la creciente destrucción de los recursos naturales, en un sistema que a todas luces ha dado resultados pero al mismo tiempo ha manifestado ser enormemente desigual. El presente ensayo constituye un ejercicio que pretende ir más allá de constituir una simple diatriba frente a los límites en los que nos ha embarcado el capitalismo, más bien pretende evidenciar, a través de la recopilación de un variado acervo teórico, una serie de reflexiones sobre la necesidad de replantear los incentivos y la regulación que existe detrás del sistema, con el fin de comprender las necesidades de afinar los modelos de crecimiento que promuevan una transición mucho más equitativa hacia la asignación de responsabilidades frente al deterioro y agotamiento del planeta.

  18. Desarrollo profesional docente y aprendizaje colectivo

    Directory of Open Access Journals (Sweden)

    Carmen Montecinos

    2008-10-01

    Full Text Available En los contextos educativos actuales, marcados por la implementación de reformas a gran escala, la oferta de programas de desarrollo profesional de alta calidad para los docentes en servicio es un imperativo. Las propuestas actuales para una actualización docente que se traducen en cambios en las prácticas pedagógicas incorporan principios que ayudan a los docentes a construir, a través de redes de docentes, nuevas comprensiones de estas prácticas y su contexto. En este artículo se describen las tendencias de cambio en el diseño e implementación de programas para la formación de profesores en servicio, profundizando en modelos que sustentan un aprendizaje colectivo facilitado por pares capacitados para esa tarea. Estas propuestas tienen como propósito mejorar el aprendizaje en las aulas y por lo tanto se organizan en torno a las necesidades del establecimiento educacional conceptualizado como una organización que aprende.

  19. Planes y proyectos para un desarrollo sustentable

    Directory of Open Access Journals (Sweden)

    Mg. Arq. Jorge Montenegro

    2014-12-01

    Full Text Available La cátedra de Urbanismo I A de la Facultad de Arquitectura, Urbanismo y Diseño de la Universidad Nacional de Córdoba, considera que es fundamental educar a los alumnos en la construcción de un pensamiento crítico reflexivo, sobre la base de teorías, modelos y metodologías preocupados por el desarrollo sustentable de nuestras ciudades. En este contexto, la cátedra promueve la construcción de una visión holística sobre la ciudad, abordando los contenidos, metodologías e instrumentación específca —planes maestros, proyectos urbanos— desde los enfoques tradicionales: físico–funcional y morfológico–perceptual, los que se complementan con una mirada socioambiental del fenómeno urbano. En este artículo presentamos una síntesis de la tarea académica que desarrollamos.

  20. Ilustración, progreso y desarrollo

    Directory of Open Access Journals (Sweden)

    Parellada, Ricardo

    2009-06-01

    Full Text Available Contemporary theories of human development and human needs present themselves as enlightened and emancipatory approaches. In this paper, I argue that this responds to three reasons: 1 a renovated conception of social progress, 2 a rational approach to social life, and 3 an appeal to the autonomy of individuals. I argue further that, although economic and social thought does not pay attention to philosophical criticisms of the Enlightenment, philosophy must nevertheless examine and take into account the calls to Enlightenment and progress that come from other branches of intellectual inquiry.

    Las teorías contemporáneas de las necesidades y el desarrollo humano se presentan como ilustradas y emancipatorias. En este artículo se sostiene que esta apelación a ideas ilustradas es debida a tres razones: 1 la propuesta de una concepción renovada del progreso social, 2 la confianza en la intervención racional sobre la vida social, y 3 el énfasis en la autonomía de los individuos. Además se sostiene que, aunque el pensamiento económico y social no tenga en consideración las críticas filosóficas a la Ilustración, la filosofía debe hacerse cargo de las apelaciones a la Ilustración y el progreso procedentes de otros ámbitos intelectuales.

  1. Agricultura familiar para el desarrollo rural incluyente

    Directory of Open Access Journals (Sweden)

    Laksmi Reddiar Krishnamurthy

    2017-04-01

    Full Text Available Las comunidades indígenas Mayas de la península de Yucatán han practicado la antigua tradición de agricultura familiar, en particular los huertos caseros, para garantizar su seguridad alimentaria. Con el objetivo de mejorar la práctica tradicional considerando paradigmas de la ciencia moderna, por una parte, se colectaron datos para definir la complejidad estructural y diversidad funcional a partir de 20 huertos familiares en cinco comunidades: X - Maben, X - Pichil, X - Yatil, San José II y Melchor Ocampo; y por otra, se organizaron grupos de discusión para dilucidar la estrategia de gestión practicada por las comunidades nativas. Los resultados mostraron que los huertos son manejados principalmente por las mujeres. También mostraron que el propósito principal del crecimiento y mantenimiento de los huertos familiares es garantizar la producción de alimentos nutritivos durante todo el año. Y, por último que los huertos caseros también sirven para propósitos secundarios tales como la provisión de productos y servicios para la medicina tradicional. El estudio sugiere que se debe de promover e invertir en huertos caseros para mejorar las estrategias de desarrollo incluyente en ambientes socio-culturales y biofísicos similares.

  2. Observatorios de Desarrollo Territorial Sustentable Mendoza, Argentina.

    Directory of Open Access Journals (Sweden)

    María Elina Gudiño

    2015-03-01

    Full Text Available El observatorio de Desarrollo territorial Sustentable para Mendoza, Argentina surge en el marco de la ley 8051/09 de Ordenamiento Territorial y Usos del Suelo. Se trata de una herramienta de comunicación para la validación y el monitoreo de indicadores, políticas, planes, programas y proyectos de índole territorial. El marco teórico-metodológico se sustenta en los principios del ordenamiento territorial y el enfoque de sistemas complejos adaptativos. La estructura se diseña en una plataforma tecnológica que permite estandarizar datos, sistematizar información, construir indicadores territoriales y publicar cartografía. Una vez logrado el prototipo, se conforma “Red Territorio” como modelo de gestión que permite interactuar entre instituciones del sector público, privado, científico y ONG. Actualmente, se está trabajando en la vinculación con las instituciones que formarán parte de la experiencia piloto de Red territorio y en el ajuste de la plataforma informática que le dará sustento.

  3. Las ONG: ciencia, desarrollo y solidaridad

    Directory of Open Access Journals (Sweden)

    Bernard Hours

    2006-07-01

    Full Text Available La cooperación internacional en el campo del desarrollo ha experimentado cambios recientes y rápidos que, vinculados a la evolución de las ideologías, han ido remodelando sensiblemente las representaciones acerca de las relaciones Norte-Sur. Las ONG han adquirido un lugar importante en el marco de la co-gestión de la "aldea planetaria" junto a la investigación y ocupan un lugar que es necesario precisar, comparar y distinguir. El artículo se centra en la cuestión de las condiciones y límites de la cooperación entre investigación y las ONG, indagando si se trata de dos mundos cerrados y heterogéneos, qué complementariedades se dan entre ambos y cuáles son los beneficios para el desarrollo. Se propone una relativización de la noción de desarrollo tal como se la entendía en la década de 1960, que toma en cuenta las dificultades que conlleva el paso del conocimiento a la acción. Asimismo se analizan desde una perspectiva antropológica las metamorfosis sufridas por las representaciones de la solidaridad, desde las ideologías del desarrollo hasta las de la acción humanitaria que motivan a los actores sociales que integran las ONG.A cooperação internacional no campo do desenvolvimento experimentou recentes mudanças que, vinculado à evolução das ideologias, remodelou sensivelmente representações sobre as relações Norte-Sul. As ONGs adquiriram um lugar importante no marco duma co-gestão da "aldeia planetária" junto com a pesquisa e ocupam um lugar que é necessário especificar, comparar e distinguir. O artigo é centrado no assunto das condições e limites da cooperação entre pesquisa e o ONGs, indagando se eles constituem dois mundos fechados e heterogêneos realmente, se eles são complementários e quais sao os benefícios para o desenvolvimento. O autor aponta a uma relativização da noção de desenvolvimento como era compreendido pela década de 1960, levando em conta as dificuldades envolvidas no passo do

  4. Online dosimetric evaluation of larynx SBRT: A pilot study to assess the necessity of adaptive replanning.

    Science.gov (United States)

    Mao, Weihua; Rozario, Timothy; Lu, Weiguo; Gu, Xuejun; Yan, Yulong; Jia, Xun; Sumer, Baran; Schwartz, David L

    2017-01-01

    We have initiated a multi-institutional phase I trial of 5-fraction stereotactic body radiotherapy (SBRT) for Stage III-IVa laryngeal cancer. We conducted this pilot dosimetric study to confirm potential utility of online adaptive replanning to preserve treatment quality. We evaluated ten cases: five patients enrolled onto the current trial and five patients enrolled onto a separate phase I SBRT trial for early-stage glottic larynx cancer. Baseline SBRT treatment plans were generated per protocol. Daily cone-beam CT (CBCT) or diagnostic CT images were acquired prior to each treatment fraction. Simulation CT images and target volumes were deformably registered to daily volumetric images, the original SBRT plan was copied to the deformed images and contours, delivered dose distributions were re-calculated on the deformed CT images. All of these were performed on a commercial treatment planning system. In-house software was developed to propagate the delivered dose distribution back to reference CT images using the deformation information exported from the treatment planning system. Dosimetric differences were evaluated via dose-volume histograms. We could evaluate dose within 10 minutes in all cases. Prescribed coverage to gross tumor volume (GTV) and clinical target volume (CTV) was uniformly preserved; however, intended prescription dose coverage of planning treatment volume (PTV) was lost in 53% of daily treatments (mean: 93.9%, range: 83.9-97.9%). Maximum bystander point dose limits to arytenoids, parotids, and spinal cord remained respected in all cases, although variances in carotid artery doses were observed in a minority of cases. Although GTV and CTV SBRT dose coverage is preserved with in-room three-dimensional image guidance, PTV coverage can vary significantly from intended plans and dose to critical structures may exceed tolerances. Online adaptive treatment re-planning is potentially necessary and clinically applicable to fully preserve treatment

  5. Investigation of the dosimetric properties of an a-Si flat panel epid

    International Nuclear Information System (INIS)

    Fielding, A.L.; Jahangir, S.T.

    2004-01-01

    Full text: Electronic portal imaging devices (EPIDs) are primarily used as an electronic replacement for film to verify the set-up of radiotherapy patients based on imaged anatomy. There has recently been much interest in the use of amorphous silicon (a-Si) flat panel EPIDs for dosimetric verification in radiotherapy. The work presented here has been carried out to determine their suitability for dosimetric applications by investigating some of the basic response characteristics and the implications these might have. The measurements reported in this paper were performed using 6-MV photon beams from an Elekta Precise linear accelerator fitted with Elekta iViewGT amorphous silicon flat panel EPIDs. Measurements were performed to investigate the response of the EPID as a function of exposure and field size. Similar measurements were made with an ionisation chamber for comparison. Further measurements were carried out to investigate the response of the EPID to multiple low dose exposures (e.g. 5x2 MU) such as might be encountered in Intensity Modulated Radiotherapy (IMRT). This was compared with the response to a single high dose exposure (e.g. 10 MU) and repeated for a range of exposures. The results show the response of the EPID, to a good approximation, to be linear with dose over the range of 1 -200 MU. However, 'under-responses' in the EPID of up to 5% were seen at the lowest exposures. For multiple low dose segments the sum of the EPID responses was found to be less than the response to the same total exposure in a single large segment. This effect reduces with increase in the magnitude of the low dose segments. The variation in EPID response with field size was found to be greater than that indicated by the ionisation chamber. The results show that the a-Si detector responds to dose, to a good approximation, in a linear manner. The EPID under-response at low doses is thought to be related to the so called ghosting effect. Each image frame has a residual

  6. A dosimetric treatment planning strategy in radioembolization of hepatocarcinoma with 90Y glass microspheres.

    Science.gov (United States)

    Chiesa, C; Mira, M; Maccauro, M; Romito, R; Spreafico, C; Sposito, C; Bhoori, S; Morosi, C; Pellizzari, S; Negri, A; Civelli, E; Lanocita, R; Camerini, T; Bampo, C; Carrara, M; Seregni, E; Marchianò, A; Mazzaferro, V; Bombardieri, E

    2012-12-01

    Our goal was to limit liver toxicity and to obtain good efficacy by developing a dosimetric treatment planning strategy. While several dosimetric evaluations are reported in literature, the main problem of the safety of the treatment is rarely addressed. Our work is the first proposal of a treatment planning method for glass spheres, including both liver toxicity and efficacy issues. Fifty-two patients (series 1) had been treated for intermediated/advanced hepatocellular carcinoma (HCC) with glass spheres, according to the Therasphere® prescription of 120 Gy averaged on the injected lobe. They were retrospectively evaluated with voxel dosimetry, adopting the local deposition hypothesis. Regions of interest on tumor and non tumor parenchyma were drawn to determine the parenchyma absorbed dose, averaged also on non irradiated voxels, excluding tumor voxels. The relationship between the mean non tumoral parenchyma absorbed dose D and observed liver decompensation was analyzed. Basal Child-Pugh strongly affected the toxicity incidence, which was 22% for A5, 57% for A6, 89% for B7 patients. Restricting the analysis to our numerically richest class (basal Child-Pugh A5 patients), D median values were significantly different between toxic (median 90 Gy) and non toxic treatments (median 58 Gy) at a Mann-Withney test, (P=0.033). Using D as a marker for toxicity, the separation of the two populations in terms of area under ROC curve was 0.75, with 95% C.I. of [0.55-0.95]. The experimental Normal Tissue Complication Probability (NTCP) curve as a function of D resulted in the following values: 0%, 14%, 40%, 67% for D interval of [0-35] Gy, [35-70] Gy, [70-105] Gy, [105-140] Gy. A limit of about 70 Gy for the mean absorbed dose to parenchyma was assumed for A5 patients, corresponding to a 14% risk of liver decompensation. This result is applicable only to our administration conditions: glass spheres after a decay interval of 3.75 days. Different safety limit (40 Gy) are

  7. Understanding the dosimetric powder EPR spectrum of sucrose by identification of the stable radiation-induced radicals

    International Nuclear Information System (INIS)

    Vrielinck, H.; Vanhaelewyn, G.; Matthys, P.; Callens, F.; Kusakovskij, J.

    2014-01-01

    Sucrose, the main component of table sugar, present in nearly every household and quite radiation sensitive, is considered as an interesting emergency dosemeter. Another application of radiation-induced radicals in sugars is the detection of irradiation in sugar-containing foodstuffs. The complexity of electron paramagnetic resonance (EPR) spectra of radicals in these materials, as a result of many hyperfine interactions and the multi-compositeness of the spectra of individual sugars, complicate dose assessment and the improvement of protocols for control and identification of irradiated sugar-containing foodstuffs using EPR. A thorough understanding of the EPR spectrum of individual irradiated sugars is desirable when one wants to reliably use them in a wide variety of dosimetric applications. Recently, the dominant room temperature stable radicals in irradiated sucrose have been thoroughly characterised using EPR, electron nuclear double resonance (ENDOR) and ENDOR-induced EPR. These radicals were structurally identified by comparing their proton hyperfine and g-tensors with the results of Density Functional Theory calculations for test radical structures. In this paper, the authors use the spin Hamiltonian parameters determined in these studies to simulate powder EPR spectra at the standard X-band (9.5 GHz), commonly used in applications, and at higher frequencies, up to J-band (285 GHz), rendering spectra with higher resolution. A few pitfalls in the simulation process are highlighted. The results indicate that the major part of the dosimetric spectrum can be understood in terms of three dominant radicals, but as-yet unidentified radicals also contribute in a non-negligible way. (authors)

  8. Comparison of intraoperative dosimetric implant representation with postimplant dosimetry in patients receiving prostate brachytherapy.

    Science.gov (United States)

    Stone, Nelson N; Hong, Suzanne; Lo, Yeh-Chi; Howard, Victor; Stock, Richard G

    2003-01-01

    To compare the results of intraoperative dosimetry with those of CT-based postimplant dosimetry in patients undergoing prostate seed implantation. Seventy-seven patients with T1-T3 prostate cancer received an ultrasound-guided permanent seed implant (36 received (125)I, 7 (103)Pd, and 34 a partial (103)Pd implant plus external beam radiation therapy). The implantation was augmented with an intraoperative dosimetric planning system. After the peripheral needles were placed, 5-mm axial images were acquired into the treatment planning system. Soft tissue structures (prostate, urethra, and rectum) were contoured, and exact needle positions were registered. Seeds were placed with an applicator, and their positions were entered into the planning system. The dose distributions for the implant were calculated after interior needle and seed placement. Postimplant dosimetry was performed 1 month later on the basis of CT imaging. Prostate and urethral doses were compared, by using paired t tests, for the real-time dosimetry in the operating room (OR) and the postimplant dosimetry. The mean preimplant prostate volume was 39.8 cm(3), the postneedle planning volume was 41.5 cm(3) (psystem provides a close match to the actual delivered doses. These data support the use of this system to modify the implant during surgery to achieve more consistent dosimetry results.

  9. Legal verification of the dosimetric instrumentation using for radiation protection in Cuba

    International Nuclear Information System (INIS)

    Walwyn, A.; Morales, J.A.

    1999-01-01

    By April of 1998 the Decree law 183 of Metrology was published at the Gaceta Oficial de la Republica de Cuba. It establishes the principles and general regulations for the organisation and juridical system of the metrological activity in Cuba. In the radiation protection field this legislation promote the establishment of a verification service of radiation measuring instruments used in the practices with radiation sources in the country. The limitations of old Cuban standards of verification related to dosimetric quantities and to the types of instruments for those which these standards are applicable; and in addition, the publication of new international standards that includes the operational quantities used for the measurement of instruments, led to the elaboration of the X and Gamma Radiation Meters Used in Radiation Protection standard. The requirements of metrological aptitude are taken from some test procedures described in the International Electrotechnical Commission (IEC) standards on photon monitoring equipment. The Secondary Standard Dosimetry Laboratory of the Centre for Radiation Protection and Higiene will start the verification service of Radiation Protection instruments. The beginning of the service is an essential element in the improvement of the accuracy of ionisation radiation metrology in Cuba, and have an evident impact in the protection of the occupationally exposed workers, because having the instruments in good technical condition became a legal exigency to the users of ionisation radiation

  10. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd brachytherapy source

    International Nuclear Information System (INIS)

    Sadeghi, Mahdi; Raisali, Gholamreza; Hosseini, S. Hamed; Shavar, Arzhang

    2008-01-01

    This article presents a brachytherapy source having 103 Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model 103 Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA- 103 Pd source in water was found to be 0.678 cGy h -1 U -1 with an approximate uncertainty of ±0.1%. The anisotropy function, F(r,θ), and the radial dose function, g(r), of the IRA- 103 Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms

  11. Radiocromic film, TLD, OSL and 'Paracas Phantom' by dosimetric intercomparation in stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Paucar Jauregui, R.; Condori Marcos, P.; Vidarte Garcia, F.

    2008-01-01

    Full text: In Peru, one deals to patients with arteriovenous malformations or cerebral tumors by means of stereotactic radiosurgery, using fine photon beams of high energy of 6 MeV, generated by a linear accelerator Varian 2100 Clinac CD of the Complejo Hospitalario San Pablo in Lima, Peru. In this work we describes the 'Dosimetric Intercomparation System of the Quality Assurance Program in Stereotactic Radiosurgery of the Complejo Hospitalario San Pablo (DIS)'. The DIS allows to guarantee application of the doses with high accuracy. It shows the good performance of the Local DIS's components: dosimetry of radiocromics films, dosimetry termoluminiscent (TLD), dosimetry of optically stimulated luminescence (OSL) and an anthropomorphic phantom of head constructed locally, denominated 'Paracas Phantom'. Also, in the International DIS practiced with The University of Texas Md Anderson Cancer Center, stands out results within the ranges: a) Dose to the center of the target (RDS/Institution): 0,95-1,05; b) Treated volumen (Measured/Institution): 0,75 - 1,05; c) Ratio of measure treated volume to target volume: 1,00 - 2,00; and d) Minimum dose to target (Minimum dose/Prescription dose): >0,90. It concludes that the DIS is important for the good decision making on the radiological safety of the patients dealt with stereotactic radiosurgery. (author)

  12. Dosimetric model for antibody targeted radionuclide therapy of tumor cells in cerebrospinal fluid

    International Nuclear Information System (INIS)

    Millar, W.T.; Barrett, A.

    1990-01-01

    Although encouraging results have been obtained using systemic radioimmunotherapy in the treatment of cancer, it is likely that regional applications may prove more effective. One such strategy is the treatment of central nervous system leukemia in children by intrathecal instillation of targeting or nontargeting beta particle emitting radionuclide carriers. The beta particle dosimetry of the spine is assessed, assuming that the spinal cord and the cerebrospinal fluid compartment can be adequately represented by a cylindrical annulus. The radionuclides investigated were 90 Y, 131 I, 67 Cu, and 199 Au. It is shown that the radiation dose to the cord can be significantly reduced using short range beta particle emitters and that there is little advantage in using targeting carriers with these radionuclides. 199 Au and 67 Cu also have the advantage of having a suitable gamma emission for imaging, permitting pretherapy imaging and dosimetric calculations to be undertaken prior to therapy. If these methods prove successful, it may be possible to replace the external beam component used in the treatment of central nervous system leukemia in children by intrathecal radionuclide therapy, thus reducing or avoiding side effects such as growth and intellectual impairment

  13. Dosimetric characterization of two radium sources for retrospective dosimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Candela-Juan, C., E-mail: ccanjuan@gmail.com [Radiation Oncology Department, La Fe University and Polytechnic Hospital, Valencia 46026, Spain and Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Karlsson, M. [Division of Radiological Sciences, Department of Medical and Health Sciences, Linköping University, Linköping SE 581 85 (Sweden); Lundell, M. [Department of Medical Physics and Oncology, Karolinska University Hospital and Karolinska Institute, Stockholm SE 171 76 (Sweden); Ballester, F. [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Tedgren, Å. Carlsson [Division of Radiological Sciences, Department of Medical and Health Sciences, Linköping University, Linköping SE 581 85, Sweden and Swedish Radiation Safety Authority, Stockholm SE 171 16 (Sweden)

    2015-05-15

    Purpose: During the first part of the 20th century, {sup 226}Ra was the most used radionuclide for brachytherapy. Retrospective accurate dosimetry, coupled with patient follow up, is important for advancing knowledge on long-term radiation effects. The purpose of this work was to dosimetrically characterize two {sup 226}Ra sources, commonly used in Sweden during the first half of the 20th century, for retrospective dose–effect studies. Methods: An 8 mg {sup 226}Ra tube and a 10 mg {sup 226}Ra needle, used at Radiumhemmet (Karolinska University Hospital, Stockholm, Sweden), from 1925 to the 1960s, were modeled in two independent Monte Carlo (MC) radiation transport codes: GEANT4 and MCNP5. Absorbed dose and collision kerma around the two sources were obtained, from which the TG-43 parameters were derived for the secular equilibrium state. Furthermore, results from this dosimetric formalism were compared with results from a MC simulation with a superficial mould constituted by five needles inside a glass casing, placed over a water phantom, trying to mimic a typical clinical setup. Calculated absorbed doses using the TG-43 formalism were also compared with previously reported measurements and calculations based on the Sievert integral. Finally, the dose rate at large distances from a {sup 226}Ra point-like-source placed in the center of 1 m radius water sphere was calculated with GEANT4. Results: TG-43 parameters [including g{sub L}(r), F(r, θ), Λ, and s{sub K}] have been uploaded in spreadsheets as additional material, and the fitting parameters of a mathematical curve that provides the dose rate between 10 and 60 cm from the source have been provided. Results from TG-43 formalism are consistent within the treatment volume with those of a MC simulation of a typical clinical scenario. Comparisons with reported measurements made with thermoluminescent dosimeters show differences up to 13% along the transverse axis of the radium needle. It has been estimated that

  14. Estudio de asociación del trastorno del desarrollo de la coordinación con otros trastornos del desarrollo infantil en la ciudad de Bucaramanga

    OpenAIRE

    Salinas Velasco, Rossana Iveth; Díaz Plata, Lyda Maritza

    2016-01-01

    INTRODUCCION. El trastorno del Desarrollo de la Coordinación TDC en la infancia es una problemática importante desde la salud pública, ya que tiene repercusiones importantes desde las diferentes esferas del desarrollo: motora, cognitiva, psicosocial y emocional, por lo mismo, es frecuente la presencia de comorbilidad con otros trastornos del desarrollo infantil. Se presenta un estudio multicéntrico que caracteriza la asociación del TDC con otros trastornos del desarrollo. OBJETIVO. Determ...

  15. Asociación del trastorno del desarrollo de la coordinación con otros trastornos del desarrollo infantil en la ciudad de Cali

    OpenAIRE

    Riascos Alpala, Alexander; Velez Correa, Diana Lizeth; Acosta Alvarez, Yuri Andrea

    2016-01-01

    INTRODUCCION. El trastorno del Desarrollo de la Coordinación TDC en la infancia es una problemática importante desde la salud pública, ya que tiene repercusiones importantes desde las diferentes esferas del desarrollo: motora, cognitiva, psicosocial y emocional, por lo mismo, es frecuente la presencia de comorbilidad con otros trastornos del desarrollo infantil. Se presenta un estudio multicéntrico que caracteriza la asociación del TDC con otros trastornos del desarrollo. OBJETIVO. Determ...

  16. Determination of Dosimetric Parameters of the Second Model of Pd-103 Seed Manufactured at Agricultural, Medical and Industrial Research School

    Directory of Open Access Journals (Sweden)

    Gholamreza Raisali

    2008-06-01

    have acceptable dosimetric parameters suitable for brachytherapy applications.

  17. Dosimetric effects of edema in permanent prostate seed implants: a rigorous solution

    International Nuclear Information System (INIS)

    Chen Zhe; Yue Ning; Wang Xiaohong; Roberts, Kenneth B.; Peschel, Richard; Nath, Ravinder

    2000-01-01

    Purpose: To derive a rigorous analytic solution to the dosimetric effects of prostate edema so that its impact on the conventional pre-implant and post-implant dosimetry can be studied for any given radioactive isotope and edema characteristics. Methods and Materials: The edema characteristics observed by Waterman et al (Int. J. Rad. Onc. Biol. Phys, 41:1069-1077; 1998) was used to model the time evolution of the prostate and the seed locations. The total dose to any part of prostate tissue from a seed implant was calculated analytically by parameterizing the dose fall-off from a radioactive seed as a single inverse power function of distance, with proper account of the edema-induced time evolution. The dosimetric impact of prostate edema was determined by comparing the dose calculated with full consideration of prostate edema to that calculated with the conventional dosimetry approach where the seed locations and the target volume are assumed to be stationary. Results: A rigorous analytic solution on the relative dosimetric effects of prostate edema was obtained. This solution proved explicitly that the relative dosimetric effects of edema, as found in the previous numerical studies by Yue et. al. (Int. J. Radiat. Oncol. Biol. Phys. 43, 447-454, 1999), are independent of the size and the shape of the implant target volume and are independent of the number and the locations of the seeds implanted. It also showed that the magnitude of relative dosimetric effects is independent of the location of dose evaluation point within the edematous target volume. It implies that the relative dosimetric effects of prostate edema are universal with respect to a given isotope and edema characteristic. A set of master tables for the relative dosimetric effects of edema were obtained for a wide range of edema characteristics for both 125 I and 103 Pd prostate seed implants. Conclusions: A rigorous analytic solution of the relative dosimetric effects of prostate edema has been

  18. Agenda para el desarrollo en la ompi (primera parte

    Directory of Open Access Journals (Sweden)

    María Paula Sandoval Avella

    2008-11-01

    Full Text Available La presente investigación se encarga de revisar todo el proceso que desencadenó la propuesta inicial de Argentina y Brasil sobre Una Agenda para el Desarrollo de la ompi con los respectivos aportes de los demás países miembros tanto a favor como en contra. La propuesta argumenta que la propiedad intelectual no debe ser considerada como un fin en sí misma al estipular normas de protección de la obra o invento sin tener en cuenta el nivel de desarrollo de los países miembros, sino que, por el contrario, debe incorporar el concepto de desarrollo a las actividades de la ompi, que por ser miembro de Naciones Unidas se encuentra comprometida a cumplir con los Objetivos de Desarrollo del Milenio. Se discute de qué manera la ompi puede aportar al desarrollo. La discusión tomó varias reuniones en la Organización hasta adoptar finalmente 45 puntos. Cabe preguntarse si después de tantos debates los 45 puntos aportan realmente al desarrollo a nivel mundial. ¿Se logró el cambio en el mandato de la ompi? De ser así, ¿es realmente aplicable o es una mera declaración de principios? Para responder a ello la monografía se dividió en dos partes. En primer lugar y para argumentar el análisis, se presentará la investigación sobre conceptos propios de la discusión como el desarrollo, así como un estudio de la competencia de la ompi en la materia según su misma constitución. Luego de tener ello establecido se realizó una revisión detallada de cada una de las propuestas presentadas por los países miembros con sus respectivos argumentos, que será expuesta en esta edición hasta llegar a las 45 finalmente adoptadas. No se puede entender el desenlace si no es claro cómo fue su desarrollo. La segunda parte del trabajo se expondrá en la siguiente edición, que se refiere únicamente al análisis de cada una de las 45 propuestas al desarrollo. Para ello se agruparon por categorías definiendo a qué tipo de desarrollo podrían contribuir

  19. Dosimetric predictors of diarrhea during radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Sanguineti, Giuseppe; Endres, Eugene J.; Parker, Brent C.; Sormani, Maria Pia

    2009-01-01

    Purpose: to investigate dosimetric predictors of diarrhea during radiotherapy (RT) for prostate cancer. Patients and methods: all patients who underwent external-beam radiotherapy as part of treatment for localized prostate cancer at the University of Texas Medical Branch, Galveston, TX, USA, from May 2002 to November 2006 were extracted from the own database. From the cumulative dose-volume histogram (DVH), the absolute volumes (V-value) of intestinal cavity (IC) receiving 15, 30, and 45 Gy were extracted for each patient. Acute gastrointestinal toxicity was prospectively scored at each weekly treatment visit according to CTC (common toxicity criteria) v2.0. The endpoint was the development of peak grade ≥ 2 diarrhea during RT. Various patient, tumor, and treatment characteristics were evaluated using logistic regression. Results: 149 patients were included in the analysis, 112 (75.2%) treated with whole-pelvis intensity-modulated radiotherapy (WP-IMRT) and 37 (24.8%) with prostate-only RT, including or not including, the seminal vesicles (PORT ± SV). 45 patients (30.2%) developed peak grade ≥ 2 diarrhea during treatment. At univariate analysis, IC-V 15 and IC-V 30 , but not IC-V 45 , were correlated to the endpoint; at multivariate analysis, only IC-V 15 (p = 0.047) along with peak acute proctitis (p = 0.041) was independently correlated with the endpoint. Conclusion: these data provide a novel and prostate treatment-specific ''upper limit'' DVH for IC. (orig.)

  20. N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

    International Nuclear Information System (INIS)

    Rosenspire, K.C.; Gelbard, A.S.

    1986-01-01

    With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

  1. WE-DE-209-01: Dosimetric Benefits of DIBH

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R. [UT MD Anderson Cancer Center (United States)

    2016-06-15

    Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.

  2. Dosimetric considerations in radioimmunotherapy of patients with hepatoma

    International Nuclear Information System (INIS)

    Leichner, P.K.; Klein, J.L.; Order, S.E.

    1986-01-01

    Dosimetric studies of I-131 labeled antiferritin have provided the foundation for preparative and administrative aspects of radiolabeled antibody treatment of patients with hepatoma. Tumor response to I-131 labeled antiferritin IgG was encouraging and radioimmunotherapy with Y-90 labeled antiferritin IgG was recently initiated. For these patients, In-111 labeled antiferritin IgG was used as the imaging agent, with administered activities ranging from 0.8 - 7 mCi. Serial gamma camera imaging from 30 minutes to 6 days post injection demonstrated that 5-30% of the administered activity localized in hepatomas (8/12 patients). The mean value of the effective half-life in the tumor and liver was 2.8 d. Disappearance curves for the blood circulation, spleen, and other normal tissues were biphasic such that 50% of the activity disappeared within 24 hours post injection. The eight patients who demonstrated sufficient tumor localization where subsequently treated with Y-90 labeled antiferritin IgG. Administered activities were dependent on tumor volume and uptake of radiolabeled IgG and ranged from 8 - 20 mCi. The remaining patients were treated under other existing protocols. 10 references

  3. A comprehensive approach to age-dependent dosimetric modeling

    International Nuclear Information System (INIS)

    Leggett, R.W.; Cristy, M.; Eckerman, K.F.

    1986-01-01

    In the absence of age-specific biokinetic models, current retention models of the International Commission on Radiological Protection (ICRP) frequently are used as a point of departure for evaluation of exposures to the general population. These models were designed and intended for estimation of long-term integrated doses to the adult worker. Their format and empirical basis preclude incorporation of much valuable physiological information and physiologically reasonable assumptions that could be used in characterizing the age-specific behavior of radioelements in humans. In this paper we discuss a comprehensive approach to age-dependent dosimetric modeling in which consideration is given not only to changes with age in masses and relative geometries of body organs and tissues but also to best available physiological and radiobiological information relating to the age-specific biobehavior of radionuclides. This approach is useful in obtaining more accurate estimates of long-term dose commitments as a function of age at intake, but it may be particularly valuable in establishing more accurate estimates of dose rate as a function of age. Age-specific dose rates are needed for a proper analysis of the potential effects on estimates or risk of elevated dose rates per unit intake in certain stages of life, elevated response per unit dose received during some stages of life, and age-specific non-radiogenic competing risks

  4. A comprehensive approach to age-dependent dosimetric modeling

    International Nuclear Information System (INIS)

    Leggett, R.W.; Cristy, M.; Eckerman, K.F.

    1987-01-01

    In the absence of age-specific biokinetic models, current retention models of the International Commission of Radiological Protection (ICRP) frequently are used as a point of departure for evaluation of exposures to the general population. These models were designed and intended for estimation of long-term integrated doses to the adult worker. Their format and empirical basis preclude incorporation of much valuable physiological information and physiologically reasonable assumptions that could be used in characterizing the age-specific behavior of radioelements in humans. In this paper a comprehensive approach to age-dependent dosimetric modeling is discussed in which consideration is given not only to changes with age in masses and relative geometries of body organs and tissues but also to best available physiological and radiobiological information relating to the age-specific biobehavior of radionuclides. This approach is useful in obtaining more accurate estimates of long-term dose commitments as a function of age at intake, but it may be particularly valuable in establishing more accurate estimates of dose rate as a function of age. Age-specific dose rates are needed for a proper analysis of the potential effects on estimates of risk of elevated dose rates per unit intake in certain stages of life, elevated response per unit dose received during some stages of life, and age-specific non-radiogenic competing risks. 16 refs.; 3 figs.; 1 table

  5. Study on dosimetric properties of radiophotoluminescent glass rod detector

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong Eun; Hong, Ju Young; Suh, Tea Suk [The Catholic University of Korea, Seoul (Korea, Republic of); Shin, Dong Oh [Kyunghee Univ., Seoul (Korea, Republic of); Kim, Hee Sun [Korea Hydro and Nuclear Power Co., Ltd, Daejeon (Korea, Republic of); Lim, Chun Il; Jeong, Hee Gyo [Korea Food and Drug Administration, Seoul (Korea, Republic of)

    2006-12-15

    A radiophotoluminescent Glass Rod Detector (GRD) system has recently become commercially available. We investigate the dosimetric properties of the GRD regarding the reproducibility of signal, dose linearity and energy dependence. The reproducibility of five measurements for 50 GRDs is presented by an average of one standard deviation of each GRD and it is {+-}1.2%. It is found to be linear in response to doses of {sup 60}Co beam in the range 0.5 to 50 Gy with a coefficient of linearity of 0.9998. The energy dependence of the GRD is determined by comparing the dose obtained using cylindrical chamber to that by using the GRD. The GRD response for each beam is normalized to the response for a {sup 60}Co beam. The responses for 6 and 15 MV x-ray beams are within {+-}1.5% (1SD). The energy response of GRD for high-energy photon is almost the same as the energy dependence of LiF:Mg:Ti (TLD-100) and shows little energy dependence unlike p-type silicon diode detector. The GRDs have advantages over other detectors such diode detector, and TLD: linearity, reproducibility and energy dependency. It has been verified to be an effective device for small field dosimetry for stereotactic radiosurgery.

  6. A reticle retrofit and dosimetric consideration for a linear accelerator.

    Science.gov (United States)

    Krithivas, V

    1996-01-01

    An imperfect reticle system in an accelerator causes uncertainties in source-skin distance (SSD), off-axis distance (OAD), isocenter, and so forth. A reticle was designed and fabricated, and its implications on x-ray and electron beam dosimetry were investigated. A new reticle frame was dimensioned to fit snugly in the accelerator. The frame was fabricated to carry a pair of adjustable cross wires and to allow the machine operation in the photon and electron modes. The impact of the cross wires on 6 MV photon and 5-10 MeV electron beam parameters such as dose rate (Gy/monitor unit), beam uniformity, surface dose, and so forth, were studied using suitable ion chambers and phantoms. The retrofitted system offered long-term mechanical stability leading to precise SSD, OAD, and isocenter measurements. Changes introduced by the cross wires on the 6 MV photon and 5-10 MeV electron beams are presented. Long-term stability of a reticle in an accelerator is important for an accurate patient setup and for making reliable dosimetric measurements. Beam characteristrics have to be studied whenever modifications on a reticle system are made.

  7. Active pixel as dosimetric device for interventional radiology

    International Nuclear Information System (INIS)

    Servoli, L.; Baldaccini, F.; Biasini, M.; Checcucci, B.; Chiocchini, S.; Cicioni, R.; Conti, E.; Di Lorenzo, R.; Dipilato, A.C.; Esposito, A.; Fanó, L.; Paolucci, M.; Passeri, D.; Pentiricci, A.

    2013-01-01

    Interventional Radiology (IR) is a subspecialty of radiology comprehensive of all minimally invasive diagnostic and therapeutic procedures performed using radiological devices to obtain image guidance. The interventional procedures are potentially harmful for interventional radiologists and medical staff due to the X-ray diffusion by the patient's body. The characteristic energy range of the diffused photons spans few tens of keV. In this work we will present a proposal for a new X-ray sensing element in the energy range of interest for IR procedures. The sensing element will then be assembled in a dosimeter prototype, capable of real-time measurement, packaged in a small form-factor, with wireless communication and no external power supply to be used for individual operators dosimetry for IR procedures. For the sensor, which is the heart of the system, we considered three different Active Pixel Sensors (APS). They have shown a good capability as single X-ray photon detectors, up to several tens keV photon energy. Two dosimetric quantities have been considered, the number of detected photons and the measured energy deposition. Both observables have a linear dependence with the dose, as measured by commercial dosimeters. The uncertainties in the measurement are dominated by statistic and can be pushed at ∼5% for all the sensors under test

  8. Dosimetric intercomparison between protons and electrons therapies applied to retinoblastoma

    International Nuclear Information System (INIS)

    Braga, Flavia Vieira

    2008-01-01

    In this work we propose a construction of a simple human eye model in order to simulate the dosimetric response for a treatment with protons and electrons in a retinoblastoma cancer. The computational tool used in this simulation was the Geant4 code, in the version 4.9.1, all these package are free and permit simulate the interaction of radiation with matter. In our simulation we use a box with 4 cm side, with water, for represent the human eye. The simulation was performed considering mono energetics beams of protons and electrons with energy range between 50 and 70 MeV for protons and 2 and 10 MeV for electrons. The simulation was based on the advanced hadron therapy example of the Geant 4 code. In these example the phantom is divided in voxels with 0.2 mm side and it is generated the energy deposited in each voxel. The simulation results show the energy deliver in each voxel, with these energie we can calculate the dose deposited in that region. We can see the dose profile of, proton and electron, and we can see in both cases that for protons the position of delivered dose is well know, that happen in the position where the proton stop, for electrons the energies is delivered along the way and pass the desired position for high dose deposition. (author)

  9. Dosimetric characteristics of a MOSFET dosimeter for clinical electron beams.

    Science.gov (United States)

    Manigandan, D; Bharanidharan, G; Aruna, P; Devan, K; Elangovan, D; Patil, Vikram; Tamilarasan, R; Vasanthan, S; Ganesan, S

    2009-09-01

    The fundamental dosimetric characteristics of commercially available metal oxide semiconductor field effect transistor (MOSFET) detectors were studied for clinical electron beam irradiations. MOSFET showed excellent linearity against doses measured using an ion chamber in the dose range of 20-630cGy. MOSFET reproducibility is better at high doses compared to low doses. The output factors measured with the MOSFET were within +/-3% when compared with those measured with a parallel plate chamber. From 4 to 12MeV, MOSFETs showed a large angular dependence in the tilt directions and less in the axial directions. MOSFETs do not show any dose-rate dependence between 100 and 600MU/min. However, MOSFETs have shown under-response when the dose per pulse of the beam is decreased. No measurable effect in MOSFET response was observed in the temperature range of 23-40 degrees C. The energy dependence of a MOSFET dosimeter was within +/-3.0% for 6-18MeV electron beams and 5.5% for 4MeV ones. This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4-18MeV.

  10. Dosimetric Uncertainties in Verification of Intensity Modulated Photon Beams

    International Nuclear Information System (INIS)

    Jurkovic, S.

    2010-01-01

    The doctoral thesis presents method for the calculation of the compensators' shape to modulate linear accelerators' beams. Characteristic of the method is more strict calculation of the scattered radiation in beams with an inhomogeneous cross-section than it was before. Method could be applied in various clinical situations. It's dosimetric verification was made in phantoms, measuring dose distributions using ionization chambers as well as radiographic film. Therefore, ionization chambers were used for the evaluation of modulator shape and film was used for the evaluation of two-dimensional dose distributions. It is well known that dosimetry of the intensity modulated photon beams is rather complicated regarding inhomogeneity of the dose distribution. The main reason for that is the beam modulator which changes spectral distribution of the beam. Possibility of use different types of detectors for the measurements of dose distributions in modulated photon beams and their accuracy were examined. Small volume ionization chambers, different diodes and amorphus silicon detector and radigraphic film were used. Measured dose distributions were compared between each other as well as with distributions simulated using Monte Carlo particle transport algorithm. In this way the most accurate method for the verification of modulate photon beams is suggested. (author)

  11. Dosimetric properties of commercial glasses and sand for high doses

    International Nuclear Information System (INIS)

    Teixeira, Maria Ines

    2004-01-01

    Commercial glasses (transparent and colored) produced by Cebrace, Brazil, Sao Paulo, and sand samples of different Brazilian beaches were studied, due to their low cost and easy handling, to verify the possibility of their use in high dose dosimetry. The main dosimetric characteristics were determined using a densitometer, a spectrophotometer, a thermoluminescent (TL) reader and an electronic paramagnetic resonance system. The gamma irradiations were carried out using a Gamma-Cell 220 and a panoramic source ( 60 Co) of IPEN. An optical absorption band was observed at 420 nm in the glass samples. The TL glow curves presented peaks at 205 deg C, 135 deg C, 150 deg C and 145 deg C for the transparent, bronze, brown and green glass samples, respectively. All EPR spectra of the glasses showed Fe 3+ characteristic signals at g = 4.27 and 2.01. The gamma irradiated sand samples presented two peaks at 110 deg C and 170 deg C and an EPR signal at g= 1.999. However, these materials present a pronounced thermal fading at room temperature after irradiation. With the objective to minimize this thermal fading, both glass and sand samples were submitted to different pre- and post-irradiation thermal treatments. The glass and sand samples showed the possibility of utilization for high dose dosimetry and as Yes/No irradiation detectors. (author)

  12. Technical and dosimetric aspects of quality control in mammography

    International Nuclear Information System (INIS)

    Zoetelief, J.; Wit, N.J.P. de; Broerse, J.J.

    1989-01-01

    Before screening programmes using mammography are implemented, a cost benefit analysis has to be made and quality-control programme for the technical and dosimetric aspects adopted, including daily checks on film processing and total mammography procedure (radiography of a reference phantom, for which the average density, limiting value ± 0.20%, and focal charge is determined and which allows assessment of physical image quality) The installation of a MAs meter is essential for daily checks and can be used for determination of absorbed dose. Accurate determination of tube voltage (limiting value ±0.5 kV) is essential in regard to absorbed dose variations. Focal spot size should be measured rather than relying on the value specified by the manufacturer. The determination of the focal charge (mAs) value for actual radiographs of female breasts combined with a measurement of compressed breast thickness provides information on absorbed dose values for actual radiographs. An approximately 50 mm thick poly(methyl methacrylate) phantom can be used for determination of absorbed dose in mammography. (author)

  13. LA ACCIÓN LOCAL COMO ALTERNATIVA DE DESARROLLO

    Directory of Open Access Journals (Sweden)

    Álvaro Albán Moreno

    2005-01-01

    Full Text Available En este artículo se busca destacar el tema del desarrollo local como alternativa posible para que las comunidades busquen y definan objetivos de desarrollo acordes con su contextos y a partir de sus propias realidades y potencialidades. Esta posibilidad se enmarca en un escenario en el que se dan dos procesos que hacen del desarrollo un reto para las autoridades territoriales: la descentralización administrativa y la elección popular de alcaldes, que a su vez redefinen las funciones del Estado. De esta manera, el territorio hoy es una expresión de muchos intereses, entre ellos los de la gran empresa, que en el estadio actual de desarrollo capitalista podría configurar oportunidades, pero, simultáneamente, amenazas, teniendo en cuenta que el desarrollo en general ha estado atado al crecimiento industrial con sus beneficios y externalidades negativas de diferente clase. Así, el "desarrollo local", es fundamentalmente una opción de carácter político, no obstante lo cual las estrategias, de acuerdo con investigación del Banco Interamericano de Desarrollo, han privilegiado lo económico y sus resultados pueden ser considerados limitados. Finalmente, se destaca la complejidad y dificultades de estos procesos, a partir de una experiencia particular; pero igualmente se señalan las dimensiones alternativas y posibles de este concepto, cuando se asocian a la participación y establecimiento de redes de cooperación en una comunidad, con lo cual se trasciende lo meramente económico.

  14. Monte-Carlo simulation of the SL-ELEKTA-20 medical linear accelerator. Dosimetric study of a water phantom

    International Nuclear Information System (INIS)

    Thiam, Ch. O.

    2003-06-01

    In radiotherapy, it is essential to have a precise knowledge of the dose delivered in the target volume and the neighbouring critical organs. To be usable clinically, the models of calculation must take into account the exact characteristics of the beams used and the densities of fabrics. Today we can use sophisticated irradiation techniques and get a more precise assessment of the dose and with a better knowledge of its distribution. Thus in this report, will be detailed a simulation of the head of irradiation of accelerator SL-ELEKTA-20 in electrons mode and a dosimetric study of a water phantom. This study is carried out with the code of simulation Monte Carlo GATE adapted for applications of medical physics; the results are compared with the data obtained by the anticancer center 'Jean Perrin' on a similar accelerator. (author)

  15. A dosimetric survey of the DC1500/25/04 electron beam plant installed at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Kuntz, Florent; Somessari, Elizabeth S.R.; Silveira, Carlos G.da; Bueno, Carmen C.; Calvo, Wilson A.P.; Napolitano, Celia M.; Goncalves, Josemary A.C.; Somessari, Samir L.

    2015-01-01

    In this work we describe a dosimetric survey of the DC1500/25/04 electron beam accelerator installed in the Intense Sources of Radiation Laboratory at IPEN/CNEN-SP. As this accelerator has been used for innumerable applications in radiation processing, product surface and internal doses must be targeted and controlled via operational qualification such as beam energy, beam current, scan width and conveyor speed. The qualification of the accelerator was carried out in order to observe the current performances of the irradiation plant using Alanine (ESR) and CTA (UV Spectrophotometry) dosimeters. Energy (Electron penetration in material) calculations, scanning width/length, homogeneity and irradiation uniformity were evaluated according to ISO/ASTM 51649 and ISO11137-3, as well as process uncertainty establishment. (author)

  16. Development of the Nation-Wide Dosimetric Monitoring Network in Ukraine

    International Nuclear Information System (INIS)

    Chumak, V.; Boguslavskaya, A.; Musijachenko, A.

    2004-01-01

    Development of the nation-wide network for monitoring and registration of individual doses is being in progress in Ukraine. The need for urgent action is caused by the fact, that despite wide use of nuclear energy and radiation sources in industry and medicine, there is no centralized dose accounting system in Ukraine, existing dosimetry services operate obsolete manual TLD readers and no methodological unity is observed by the dosimetry services. Presently the mixed dosimetric monitoring is practiced in Ukraine. Nuclear power plants and some major nuclear facilities have their own dosimetry services responsible for dosimetric monitoring of workers. Rest of occupationally exposed persons is monitored by territorial dosimetry laboratories affiliated to sanitary and epidemiology supervision bodies. In total these services cover about 38,000 occupationally exposed workers, including 5,500 in medicine, 16,400 employees of five nuclear power plants and about 16,000 workers dealing with other sources of occupational exposure (industry, research, military). It is prescribed by the governmental decree that three-level united state system assigned to covering all aspects of efficient dosimetric monitoring should be established. The tasks of the system, in particular, are: securing methodical unity of individual dosimetric monitoring; scientific and methodological guidance of individual dosimetric control; procurement of common technical policy regarding nomenclature and operation of instrumentation; implementation of quality assurance programs; development and support of information infrastructure for logging, storage and access to data on individual dosimetric monitoring, in particular - keeping the national registry of individual doses; training and certification of personnel engaged in the system of individual dosimetric monitoring. In its development, the national system will be guided by international experience and will be established according to the best practices

  17. Agenda para el desarrollo en la OMPI (segunda parte

    Directory of Open Access Journals (Sweden)

    María Paula Sandoval Avella

    2009-11-01

    Full Text Available Esta es la segunda parte de la monografía sobre las propuestas en torno a una Agenda para el Desarrollo de la OMPI. El debate en las cumbres gira en torno a cómo la ompi puede contribuir al desarrollo, si es realmente por medio de una mayor protección para generar incentivos o si se debe asegurar que el interés público prevalezca y todos los países puedan acceder a la obra o invento. Si la respuesta son los dos, la ompi debe plantear cómo resolver esta dicotomía dado que el conocimiento no se puede excluir a unos pocos, pero tampoco se puede desconocer que se necesitan incentivos para que los autores e inventores los generen y expongan. Ahora, luego de haber revisado todo el proceso teniendo claros los conceptos que involucra el tema, las competencias y limitaciones de la ompi y conociendo al detalle las propuestas de los países miembros, es posible realizar el análisis de las propuestas adoptadas y determinar su aporte al desarrollo. Como el desarrollo involucra varios ámbitos se distribuyeron las propuestas por categorías para determinar a qué ámbito de desarrollo contribuyen las medidas finalmente adoptadas de la siguiente manera, de acuerdo con el mandato de Naciones Unidas: 1. desarrollo económico; 2. formación de capacidades humanas; 3. generación de oportunidades iguales y 4. contribución a los Objetivos de Desarrollo del Milenio. La idea es analizar prospectivamente las consecuencias que se derivarían de la aplicación de las medidas adoptadas en el funcionamiento de la ompi en materia de desarrollo. Finalmente se presentan las conclusiones que se orientan a determinar si después de tan largo proceso las medidas realmente contribuyen al desarrollo o pueden caer en una simple declaración de principios.

  18. Profesores universitarios: contextos organizativos y desarrollo profesional

    Directory of Open Access Journals (Sweden)

    Adriana GEWERC BARUJEL

    2009-11-01

    Full Text Available RESUMEN: Este trabajo se inscribe en el marco de un proyecto de investigación sobre la identidad profesional de los profesores universitarios actualmente en pleno proceso de desarrollo en la Universidad de Santiago de Compostela. Su propósito básico es examinar las relaciones entre identidad profesional de profesores universitarios y los contextos organizativos en donde ésta se construye cotidianamente. La escasez de investigaciones sobre la enseñanza del profesorado universitario constituye una queja de la mayoría de los especialistas. Esta situación hace que, frecuentemente, se elaboren propuestas de formación para un profesor universitario que apenas se conoce, en función de un modelo teórico al que se pretende llegar, desde los presupuestos de investigaciones con profesores de otros niveles... ignorando cómo se desarrollan los procesos de enseñar y aprender en el seno de la institución, cuáles son las características peculiares de la socialización de estos profesores, cómo influye la cultura de la institución en la práctica cotidiana de la enseñanza, cómo está condicionada ésta por las exigencias disciplinares, cuál ha sido el proceso histórico de estas configuraciones... El conocimiento de éstas cuestiones contribuiría a tomar decisiones más fundamentadas sobre la formación y el desarrollo profesional de los profesionales de la enseñanza universitaria. En este marco, el contenido de este trabajo se estructura en tres apartados. El primero aborda el significado que tiene ser profesor universitario desde la perspectiva de indagación del concepto de identidad profesional. El segundo examina cómo condicionan esos significados los contextos organizativos en los que se desarrolla la práctica de los profesores universitarios. Finalmente, se plantean algunas hipótesis de trabajo acerca del desarrollo profesional. Los datos están extraídos del-análisis de entrevistas en profundidad realizadas a 15 catedr

  19. Preliminary dosimetric methodology for a new cobalt-60 irradiator for radioinduced necrosis

    International Nuclear Information System (INIS)

    Moura, Eduardo S.; Mosca, Rodrigo C.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Mathor, Monica B.; Sakuraba, Roberto K.; Goncalves, Vinicius D.

    2011-01-01

    The use of ionizing radiation in medical procedures, as radiotherapy, is a well-established clinical process and it has been used for several decades with good clinical results and continuous technology development for treatment optimization. On the contrary, some injuries such as necrosis, may occur with patients, due to wrong administration of the absorbed dose or with expected side effects. To evaluate how these injuries could be investigated and how they can be treated, a new Cobalto-60 irradiator was developed to induce radionecrosis in mice. This irradiator is composed by a cylindrical size and it was set up with eleven Cobalt-60 sources aligned in the surface of a cylindrical lead. This alignment guarantees a small dose focal area in a longitudinal table, with proper frames for positioning mice precisely during the irradiations period. The dosimetric procedure will measure the absorbed dose in the dose focal area, delimited the area of irradiation with penumbra regions (gradients absorbed dose profiles) and others anatomical regions of the mice with high radiosensitivity. Possible dosimetric procedures and related devices will be present in this work,. The obtained dosimetric data will be applied to ensure the accurate period of radiation of a given position. This preliminary study assures that the fundamental dosimetric process of this new Cobalt-60 irradiator and it predicates that dosimetric processes area feasible to be conducted. (author)

  20. Preliminary dosimetric methodology for a new cobalt-60 irradiator for radioinduced necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo S.; Mosca, Rodrigo C.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Mathor, Monica B., E-mail: esmoura@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sakuraba, Roberto K.; Goncalves, Vinicius D. [Hospital Israelita Albert Einstein (HIAE), Sao Paulo, SP (Brazil)

    2011-07-01

    The use of ionizing radiation in medical procedures, as radiotherapy, is a well-established clinical process and it has been used for several decades with good clinical results and continuous technology development for treatment optimization. On the contrary, some injuries such as necrosis, may occur with patients, due to wrong administration of the absorbed dose or with expected side effects. To evaluate how these injuries could be investigated and how they can be treated, a new Cobalto-60 irradiator was developed to induce radionecrosis in mice. This irradiator is composed by a cylindrical size and it was set up with eleven Cobalt-60 sources aligned in the surface of a cylindrical lead. This alignment guarantees a small dose focal area in a longitudinal table, with proper frames for positioning mice precisely during the irradiations period. The dosimetric procedure will measure the absorbed dose in the dose focal area, delimited the area of irradiation with penumbra regions (gradients absorbed dose profiles) and others anatomical regions of the mice with high radiosensitivity. Possible dosimetric procedures and related devices will be present in this work,. The obtained dosimetric data will be applied to ensure the accurate period of radiation of a given position. This preliminary study assures that the fundamental dosimetric process of this new Cobalt-60 irradiator and it predicates that dosimetric processes area feasible to be conducted. (author)

  1. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Lorchel, F.

    2007-04-01

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

  2. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source.

    Science.gov (United States)

    Richardson, Susan; Garcia-Ramirez, Jose; Lu, Wei; Myerson, Robert J; Parikh, Parag

    2012-11-01

    To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent(®) Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy∕min while the RT-50 is 10-12 Gy∕min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately ±5.2%. The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.

  3. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source

    International Nuclear Information System (INIS)

    Richardson, Susan; Garcia-Ramirez, Jose; Lu Wei; Myerson, Robert J.; Parikh, Parag

    2012-01-01

    Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent ® Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10–12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately ±5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.

  4. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Susan; Garcia-Ramirez, Jose; Lu Wei; Myerson, Robert J.; Parikh, Parag [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201 (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

    2012-11-15

    Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.

  5. Dosimetry through the Secondary Laboratory of Dosimetric Calibration of Mexico

    International Nuclear Information System (INIS)

    Tovar M, V.M.; Alvarez R, J.T.; Medina O, V.P.; Vergara M, F.; Anaya M, R.; Cejudo A, J.; Salinas L, B.

    2004-01-01

    In the beginnings of the sixty years an urgent necessity is presented mainly in the developing countries, of improving in important form the accuracy in the dosimetry of external faces in therapy of radiations (radiotherapy centers), mainly in the calibration of c linical dosemeters . In 1976 the International Atomic Energy Agency, (IAEA), and the World Health Organization, (WHO), they carried out a mutual agreement with regard to the establishment and operation of a net of Secondary Patron Laboratories of Dosimetry, (LSCD). The necessity to establish measure patterns in the field of the dosimetry of the ionizing radiations, is necessary, to have an accuracy but high in the dosimetry of the radiation beams in therapy which is highly dependent of the dose given to the tumor of those patient with cancer. Similar levels of accuracy are required in protection measures to the radiation with an acceptable smaller accuracy, however, when the personal dosemeters are used to determine the doses received by the individuals under work conditions, such mensurations in therapy of radiations and radiological protection will have traceability through a chain of comparisons to primary or national patterns. The traceability is necessary to assure the accuracy and acceptability of the dosimetric measures, as well as, the legal and economic implications. The traceability is also necessary in the dosimetry of high dose like in the sterilization of different products. The main function of the LSCD is to provide a service in metrology of ionizing radiations, maintaining the secondary or national patterns, which have a traceability to the International System of measures, which is based for if same in the comparison of patterns in the Primary Laboratories of Dosimetry (LPD) under the auspice of the International Office of Weights and Measure (BIPM). The secondary and national patterns in the LSCD constitute in Mexico, the national patterns of the magnitudes in the dosimetry of the

  6. Dosimetric aspects of radiation processing of food and allied products

    International Nuclear Information System (INIS)

    Sharma, G.; Bhat, R.M.; Bhatt, B.C.

    2010-01-01

    Full text: Gamma radiation processing in the last 4-5 decades is continuously gaining importance in processing of a wide variety of products, as it can modify physical, chemical and biological properties of the materials, including food and allied products on industrial scale due its inherent qualities like ease of processing in finally packaged form, eco-friendly nature and other obvious reasons over conventional means of processing. Food and allied products are either from agricultural produce or animal origin; they get easily contaminated from soil during harvesting, handling, processing, environment conditions, storage and transport from various types of micro-organisms including pathogens. In many countries it is mandatory to bring down the population of micro-organisms to an acceptable level and complete elimination of pathogens before such products are accepted for human or animal consumption. Processing of food and allied products by radiation has its own challenges due to wider public acceptance of irradiated food, a wide range, 0.25-50kGy, of absorbed dose requirements for different category of such products and purposes, use of a variety of packaging materials in different shapes and sizes and because of its perishable nature. More than 50 countries including India in the world have accepted radiation processing of food and allied products by radiation. Dosimetry is an important aspect of radiation processing, whether it is food or allied product. Uniformity in dose delivered to these products depends on several factors such as product carrier to source frame alignment, product carrier and product/tote box design, product loading pattern, attenuation due to product thickness, product bulk density that varies from 0.1-1.0 kg/l and the plant design whether during processing product overlaps the source or otherwise. In this presentation dosimetric aspects of radiation processing of food and allied products and problems associated with dosimetry of such

  7. Desarrollo y medio ambiente. Algunas miradas desde las ciencias sociales

    Directory of Open Access Journals (Sweden)

    Enrique Pérez

    2009-01-01

    Full Text Available En este trabajo, se presentan algunas de las teorías que atañen a la relación entre medio ambiente y desarrollo y se plantean interrogantes sobre la forma en que la temática ha sido desarrollada por parte de los científicos sociales. Su objetivo es doble: a de mostrar la polisemia del concepto desarrollo en las teorías económicas y la necesidad de que éstas incorporen indicadores más allá del de la renta (tales como el género, la postmodernidad, el postcolonialismo y los sujetos sociales; b destacar el importante trabajo, principalmente político, de varias de las teorías en cuestiones de medio ambiente y desarrollo.

  8. Cultura y desarrollo integral: viejos ideales, nuevas estrategias.

    Directory of Open Access Journals (Sweden)

    Winston Manuel Licona Calpe

    2013-11-01

    Full Text Available Esta ponencia establece la relación entre cultura y desarrollo en función de una sostenibilidad equitativa y socialmente responsable en la búsqueda de criterios e instrumentos para el incremento de la calidad de vida desde el sector cultural. Para ese efecto, en una primera parte relaciona los términos buscando la resemantización de los mismos. En la segunda parte, presenta los rasgos más característicos de las antinomias y sinsentidos de la cultura y el desarrollo. En la tercera parte, propone avanzar en una metodología genérica la reconstrucción estratégica del sector cultural. Y, por último, en la cuarta parte, relaciona la cultura y el desarrollo en una perspectiva integradora de lo local y lo global desde el sector cultural.

  9. Pautas de crianza y desarrollo socioafectivo en la infancia

    Directory of Open Access Journals (Sweden)

    Ángela Cuervo Martinez

    2010-01-01

    Full Text Available Este artículo presenta una revisión y hace unas reflexiones sobre la relación entre las pautas y los estilos de crianza y el desarrollo socioafectivo durante la infancia, a partir de los aportes de investigaciones realizadas sobre el tema, asumiendo que la salud mental de los padres, las pautas de crianza y el desarrollo socioafectivo de los niños y niñas están muy relacionados, y que cambian según la multidimensionalidad de variables evolutivas y contextuales. Finalmente, se considera la importancia de la familia para facilitar el desarrollo de conductas prosociales y la autorregulación emocional y para la prevención de problemas de salud mental en la infancia como depresión, agresividad, baja autoestima y ansiedad, entre otras.

  10. Medio ambiente, ecología y desarrollo en Colombia

    Directory of Open Access Journals (Sweden)

    Camilo Antonio Bohórquez Bohórquez

    2008-01-01

    Full Text Available Colombia tiene unas características ambientales y ecológicas propias del neotrópico, que la hacen específica y única; sin embargo, los modelos de desarrollo implementados van en contravía de estas características. El artículo muestra cómo las polí- ticas gubernamentales desconocen las características inherentes al desarrollo humano sustentable, lo cual genera graves problemas ambientales urbanos y rurales. En contraposición se establecen algunos lineamientos generales para estructurar una propuesta de desarrollo basado en las características ecológicas colombianas.

  11. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mary, E-mail: maryfeng@umich.edu [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Normolle, Daniel [Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Pan, Charlie C. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Dawson, Laura A. [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Amarnath, Sudha [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Ensminger, William D. [Department of Internal Medicine, Division of Hematology Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Lawrence, Theodore S.; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)

    2012-09-01

    Purpose: Radiation-induced gastric bleeding has been poorly understood. In this study, we described dosimetric predictors for gastric bleeding after fractionated radiation therapy. Methods and Materials: The records of 139 sequential patients treated with 3-dimensional conformal radiation therapy (3D-CRT) for intrahepatic malignancies were reviewed. Median follow-up was 7.4 months. The parameters of a Lyman normal tissue complication probability (NTCP) model for the occurrence of {>=}grade 3 gastric bleed, adjusted for cirrhosis, were fitted to the data. The principle of maximum likelihood was used to estimate parameters for NTCP models. Results: Sixteen of 116 evaluable patients (14%) developed gastric bleeds at a median time of 4.0 months (mean, 6.5 months; range, 2.1-28.3 months) following completion of RT. The median and mean maximum doses to the stomach were 61 and 63 Gy (range, 46-86 Gy), respectively, after biocorrection of each part of the 3D dose distributions to equivalent 2-Gy daily fractions. The Lyman NTCP model with parameters adjusted for cirrhosis predicted gastric bleed. Best-fit Lyman NTCP model parameters were n=0.10 and m=0.21 and with TD{sub 50} (normal) = 56 Gy and TD{sub 50} (cirrhosis) = 22 Gy. The low n value is consistent with the importance of maximum dose; a lower TD{sub 50} value for the cirrhosis patients points out their greater sensitivity. Conclusions: This study demonstrates that the Lyman NTCP model has utility for predicting gastric bleeding and that the presence of cirrhosis greatly increases this risk. These findings should facilitate the design of future clinical trials involving high-dose upper abdominal radiation.

  12. A revised dosimetric model of the adult head and brain

    International Nuclear Information System (INIS)

    Bouchet, L.G.; Bolch, W.E.; Weber, D.A.

    1996-01-01

    During the last decade, new radiopharmaceutical have been introduced for brain imaging. The marked differences of these tracers in tissue specificity within the brain and their increasing use for diagnostic studies support the need for a more anthropomorphic model of the human brain and head. Brain and head models developed in the past have been only simplistic representations of this anatomic region. For example, the brain within the phantom of MIRD Pamphlet No. 5 Revised is modeled simply as a single ellipsoid of tissue With no differentiation of its internal structures. To address this need, the MIRD Committee established a Task Group in 1992 to construct a more detailed brain model to include the cerebral cortex, the white matter, the cerebellum, the thalamus, the caudate nucleus, the lentiform nucleus, the cerebral spinal fluid, the lateral ventricles, and the third ventricle. This brain model has been included within a slightly modified version of the head model developed by Poston et al. in 1984. This model has been incorporated into the radiation transport code EGS4 so as to calculate photon and electron absorbed fractions in the energy range 10 keV to 4 MeV for each of thirteen sources in the brain. Furthermore, explicit positron transport have been considered, separating the contribution by the positron itself and its associated annihilations photons. No differences are found between the electron and positron absorbed fractions; however, for initial energies of positrons greater than ∼0.5 MeV, significant differences are found between absorbed fractions from explicit transport of annihilation photons and those from an assumed uniform distribution of 0.511-MeV photons. Subsequently, S values were calculated for a variety of beta-particle and positron emitters brain imaging agents. Moreover, pediatric head and brain dosimetric models are currently being developed based on this adult head model

  13. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    International Nuclear Information System (INIS)

    Feng, Mary; Normolle, Daniel; Pan, Charlie C.; Dawson, Laura A.; Amarnath, Sudha; Ensminger, William D.; Lawrence, Theodore S.; Ten Haken, Randall K.

    2012-01-01

    Purpose: Radiation-induced gastric bleeding has been poorly understood. In this study, we described dosimetric predictors for gastric bleeding after fractionated radiation therapy. Methods and Materials: The records of 139 sequential patients treated with 3-dimensional conformal radiation therapy (3D-CRT) for intrahepatic malignancies were reviewed. Median follow-up was 7.4 months. The parameters of a Lyman normal tissue complication probability (NTCP) model for the occurrence of ≥grade 3 gastric bleed, adjusted for cirrhosis, were fitted to the data. The principle of maximum likelihood was used to estimate parameters for NTCP models. Results: Sixteen of 116 evaluable patients (14%) developed gastric bleeds at a median time of 4.0 months (mean, 6.5 months; range, 2.1-28.3 months) following completion of RT. The median and mean maximum doses to the stomach were 61 and 63 Gy (range, 46-86 Gy), respectively, after biocorrection of each part of the 3D dose distributions to equivalent 2-Gy daily fractions. The Lyman NTCP model with parameters adjusted for cirrhosis predicted gastric bleed. Best-fit Lyman NTCP model parameters were n=0.10 and m=0.21 and with TD 50 (normal) = 56 Gy and TD 50 (cirrhosis) = 22 Gy. The low n value is consistent with the importance of maximum dose; a lower TD 50 value for the cirrhosis patients points out their greater sensitivity. Conclusions: This study demonstrates that the Lyman NTCP model has utility for predicting gastric bleeding and that the presence of cirrhosis greatly increases this risk. These findings should facilitate the design of future clinical trials involving high-dose upper abdominal radiation.

  14. Validation and dosimetric evaluation employing the techniques of TL and OSL of thermoluminescent materials for application in the dosimetry of clinical beams of electrons used in total irradiation of the skin - TSI; Validação e avaliação dosimétrica empregando as técnicas de TL e OSL de materiais termoluminescentes para aplicação na dosimetria de feixes clínicos de elétrons utilizados na irradiação total da pele

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Shirlane Barbosa de

    2017-07-01

    In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. TSI dosimetry is difficult because of the complexity of the treatment in assessing dose uniformity and measuring the dose absorbed at shallow depths throughout the skin surface extent, resulting in a wide variation in dose distribution. The TLDs have proven to be very useful for the distribution and verification of the dose prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. Several types of dosimeters have been used in the radiotherapy sectors, the most commonly used are Lithium Fluride (TLD-100), where it obtains a long history in this type of application. New dosimetric materials have gained great importance in the dosimetry of clinical electron beams, such as Dysprosium-doped Calcium Sulphate (TL) and Carbon doped (OSL) based Aluminum Oxide, This work evaluates the performance of the respective thermoluminescent dosimeters and the optically stimulated luminescence in the dosimetry of clinical electron beams used in total irradiation of the skin. (author)

  15. SU-F-BRA-14: Optimization of Dosimetric Guidelines for Accelerated Partial Breast Irradiation (APBI) Using the Strut-Adjusted Volume Implant (SAVI)

    International Nuclear Information System (INIS)

    Mooney, K; Altman, M; Garcia-Ramirez, J; Thomas, M; Zoberi, I; Mullen, D; DeWees, T; Esthappan, J

    2015-01-01

    Purpose: Treatment planning guidelines for accelerated partial breast irradiation (ABPI) using the strut-adjusted volume implant (SAVI) are inconsistent between the manufacturer and NSABP B-39/RTOG 0413 protocol. Furthermore neither set of guidelines accounts for different applicator sizes. The purpose of this work is to establish guidelines specific to the SAVI that are based on clinically achievable dose distributions. Methods: Sixty-two consecutive patients were implanted with a SAVI and prescribed to receive 34 Gy in 10 fractions twice daily using high dose-rate (HDR) Ir-192 brachytherapy. The target (PTV-EVAL) was defined per NSABP. The treatments were planned and evaluated using a combination of dosimetric planning goals provided by the NSABP, the manufacturer, and our prior clinical experience. Parameters evaluated included maximum doses to skin and ribs, and volumes of PTV-EVAL receiving 90%, 95%, 100%, 150%, and 200% of the prescription (V90, etc). All target parameters were evaluated for correlation with device size using the Pearson correlation coefficient. Revised dosimetric guidelines for target coverage and heterogeneity were determined from this population. Results: Revised guidelines for minimum target coverage (ideal in parentheses): V90≥95%(97%), V95≥90%(95%), V100≥88%(91%). The only dosimetric parameters that were significantly correlated (p<0.05) with device size were V150 and V200. Heterogeneity criteria were revised for the 6–1 Mini/6-1 applicators to V150≤30cc and V200≤15cc, and unchanged for the other sizes. Re-evaluation of patient plans showed 90% (56/62) met the revised minimum guidelines and 76% (47/62) met the ideal guidelines. All and 56/62 patients met our institutional guidelines for maximum skin and rib dose, respectively. Conclusions: We have optimized dosimetric guidelines for the SAVI applicators, and found that implementation of these revised guidelines for SAVI treatment planning yielded target coverage exceeding

  16. Calidad en el desarrollo de Sistemas de Software

    OpenAIRE

    Pesado, Patricia Mabel; Bertone, Rodolfo Alfredo; Esponda, Silvia; Pasini, Ariel C.; Martorelli, Sabrina Lorena

    2010-01-01

    El objetivo del subproyecto “Calidad en el desarrollo de Sistemas de Software" es analizar, investigar y desarrollar propuestas en temas relacionados con el aseguramiento de la calidad en cada una de las etapas del desarrollo de Sistemas de Software. En particular se ha trabajado y estudiado las normas de calidad más ampliamente difundidas, líneas ISO y CMMI, y su incidencia en entornos como la pequeña y mediana industria de nuestro país. Desde el año 2006, se ha trabajado en la adecuación...

  17. Estado actual de fruticultura colombiana y perspectivas para su desarrollo

    OpenAIRE

    Lasprilla, Diego Miranda

    2011-01-01

    La horticultura en Colombia comprende las áreas de floricultura, fruticultura, olerícultura, producción de plantas aromáticas y medicinales y la horticultura urbana. La promoción y desarrollo del sector frutícola representa para Colombia una importante fuente de crecimiento de la agricultura, de generación de empleo rural y de desarrollo con equidad para las distintas regiones puesto que las frutas pueden asentarse en los diversos pisos térmicos de que dispone el país, a la vez que conforma u...

  18. Desarrollo del lenguaje oral en el niño :

    OpenAIRE

    Ara Acín, Belén

    2012-01-01

    El desarrollo del lenguaje oral es un aspecto fundamental del niño/a, ya que cumple una función no solamente de comunicación, sino también de socialización, humanización, del pensamiento y autocontrol de la propia conducta. Por todo ello, es muy importante la estimulación por parte del ambiente familiar, un entorno rico en estímulos, experiencias, contacto y afecto contribuirá al buen desarrollo del lenguaje en el niño/a

  19. Nuevas pistas en la antropología del desarrollo

    Directory of Open Access Journals (Sweden)

    Ana Toledo Chávarri

    2007-05-01

    Full Text Available El seminario “Nuevas pistas en antropología del desarrollo” formó parte de las actividades de revisión anuales que se organizaron en L'Ecole de Hautes Etudes en Sciences Sociales (EHESS. En esta ocasión, Jean Pierre Olivier de Sardan fue el encargado de dirigir este encuentro que pretendía describir las transformaciones ocurridas en las formas de ayuda al desarrollo y en las interacciones entre instituciones de desarrollo y las poblaciones destinatarias.

  20. ECOLOGÍA Y DESARROLLO RURAL. UN ENFOQUE GENERAL

    OpenAIRE

    Fernández Alvarado, Francisco

    2011-01-01

    En este artículo se aprecia el aporte de la ecología en el desarrollo rural; se visualizan los desequilibrios en el medio ambiente engendrados por la deforestación y la reforestación, que conllevan a prácticas monocultivistas.  Por otra parte aparece la práctica policultivo, como factor favorable al desarrollo rural y finalmente, a modo de conclusión, se hace referencia al problema de la irracionalidad ecológica y la legislación ambiental, que se caracteriza por su carácter sectorial en el de...

  1. Los países en desarrollo y el Gatt

    OpenAIRE

    Manero Salvador, Ana María

    2008-01-01

    Ejemplar monográfico: 60 años del sistema GATT-OMC La preocupación por el impacto de las reglas comerciales multilaterales en el desarrollo es muy anterior a la Ronda de Doha de la OMC pues se remonta a la Carta de la Habana, negociada y adoptada en los albores del GATT (pero que nunca entró en vigor, como es sabido). Al analizar la evolución de esas reglas en los últimos 60 años se muestra la utilidad del concepto genérico de «trato desigual» (hacia los países en desarrollo...

  2. Desarrollo SaaS con Ruby on Rails

    OpenAIRE

    Peralta Calvo, Alfonso

    2015-01-01

    Con el objetivo de liberar a los dispositivos finales de lógica de cómputo, muchas veces esta se traslada al servidor y estos terminales simplemente se tienen que ocupar de consultar información. Las aplicaciones web se alojan en la nube y hacen el desarrollo y el mantenimiento más sencillos. En este Trabajo de Fin de Grado se ha implementado una aplicación web accesible por navegador y desarrollada con metodologías ágiles. Mediante una serie de herramientas y ténicas de desarrollo se ha c...

  3. El desarrollo industrial y su impacto en el medio ambiente

    OpenAIRE

    Suárez Tamayo, Susana; Molina Esquivel, Enrique

    2014-01-01

    El desarrollo industrial induce una fuerte reactivación socioeconómica y mejoras en la calidad de vida de la población, por otro lado puede provocar importantes modificaciones que ocasionan el desequilibrio de ecosistemas, diversas formas de contaminación y otros problemas ambientales y sociales. Por lo anterior se decide exponer los elementos esenciales del tema que nos ocupa acorde a la política ambiental del desarrollo industrial que está regida por las organizaciones internacionales. Se p...

  4. Desarrollos urbanos e inversiones turísticas costeras

    Directory of Open Access Journals (Sweden)

    Patricio Aguirre Herrera

    2008-11-01

    Full Text Available La ordenación del territorio en áreas turísticas sigue frecuentemente las mismas estrategias de desarrollo espacial que los territorios o espacios urbanos. Sus definiciones iniciales, desarrollos conceptuales y descripciones territoriales, presentan claros paralelismos. Sin embargo, no resulta claro que esta importante actividad económica deba seguir ordenándose según una normativa meramente residencial, que no reconozca sus peculiaridades. Este trabajo, pretende valorizar la necesidad de un tratamiento de espacios y periferias turísticas, centrado en términos de sustentabilidad como clave del mantenimiento de la competitividad y dinamismo de los ambientes litorales.

  5. Medio ambiente, ecología y desarrollo en Colombia

    OpenAIRE

    Camilo Antonio Bohórquez Bohórquez

    2008-01-01

    Colombia tiene unas características ambientales y ecológicas propias del neotrópico, que la hacen específica y única; sin embargo, los modelos de desarrollo implementados van en contravía de estas características. El artículo muestra cómo las polí- ticas gubernamentales desconocen las características inherentes al desarrollo humano sustentable, lo cual genera graves problemas ambientales urbanos y rurales. En contraposición se establecen algunos lineamientos generales para estructurar una pro...

  6. El desarrollo social del niño

    OpenAIRE

    Valcarcel Gonzalez, Ma. del Pilar

    1986-01-01

    Se consideran tres factores que intervienen en el desarrollo social del niño: aprendizaje social, normatividad ético-social y relaciones interpersonales (familia, escuela y grupo de iguales). El aprendizaje social es estudiado según el modelo conductista (Bandura /Walters, Miller/Dollard), y en la atención a las normas se tiene en cuenta el esquema de desarrollo propuesto por Piaget. On considerère 3 facteurs qui interviennent dans le développement social de l'enfant: apprentissage social,...

  7. HISTORIAS DE APRENDIZAJE: UNA HERRAMIENTA PARA EL DESARROLLO ORGANIZACIONAL

    Directory of Open Access Journals (Sweden)

    Ana Cristina Marín Fernández

    2001-01-01

    Full Text Available El presente artículo parte de una reflexión acerca de la importancia del aprendizaje al interior de las organizaciones en función de su desarrollo organizacional. Presenta una reseña de la metodología de historias de aprendizaje desarrollada por los profesores Art Kleiner y George Roth, en el Center for Organizational Learning y el Reflection Learning Associates de MIT, como una herramienta de tipo administrativo, utilizada para promover el aprendizaje y el desarrollo organizacional.

  8. Dosimetric response of united, commercially available CTA foils for sup 6 sup 0 Co gamma rays

    CERN Document Server

    Peimel-Stuglik, Z

    2001-01-01

    The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for sup 6 sup 0 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for sup 6 sup 0 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life.

  9. Dosimetric assessment of the PRESAGE dosimeter for a proton pencil beam

    International Nuclear Information System (INIS)

    Wuu, C-S; Qian, X; Xu, Y; Adamovics, J; Cascio, E; Lu, H-M

    2013-01-01

    The objective of this study is to assess the feasibility of using PRESAGE dosimeters for proton pencil beam dosimetry. Two different formulations of phantom materials were tested for their suitability in characterizing a single proton pencil beam. The dosimetric response of PRESAGE was found to be linear up to 4Gy. First-generation optical CT scanner, OCTOPUS TM was used to implement dose distributions for proton pencil beams since it provides most accurate readout. Percentage depth dose curves and beam profiles for two proton energy, 110 MeV, and 93 MeV, were used to evaluate the dosimetric performance of two PRESAGE phantom formulas. The findings from this study show that the dosimetric properties of the phantom materials match with basic physics of proton beams.

  10. Dosimetric response of united, commercially available CTA foils for 60Co gamma rays

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Z.

    2001-01-01

    The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for 60 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for 60 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life. (author)

  11. Dosimetric optimization of worksite involving the installation of VATS containing highly active effluent

    International Nuclear Information System (INIS)

    Legee, F.; Busani, J.; Madigand, Y.; Pailloux, J.

    1996-01-01

    Within the framework of safety improvements at the CEA, CEA-FAR, concerned to formalize the ALARA initiative, has carried out for information and training purpose and to create awareness a dosimetric assessment of the worksite where new storage vats for highly active effluents are to be installed. The approach used for this worksite is global. Techniques used were all complementary, ensuring constant elaboration, experiment follow-up and feedback of a worksite at a relatively low dosimetric cost (an estimated 36 men.mSv brought down to 30 men.mSv through implementation of the ALARA principle). This type of global conception of radioprotection involving all the employees (head of project, project managers, companies, radioprotection employees...) which today proves its worth on a modest worksite must now be extended to worksites of a broader scope (several hundreds of men.mSv) where fulfillment of the dosimetric objectives is a major stake. (author)

  12. Multibeam radiation therapy treatment application

    International Nuclear Information System (INIS)

    Manens, J.P.; Le Gall, G.; Chenal, C.; Ben Hassel, M.; Fresne, F.; Barillot, C.; Gibaud, B.; Lemoine, D.; Bouliou, A.; Scarabin, J.M.

    1991-01-01

    A software package has been developed for multibeam radiation therapy treatment application. We present in this study a computer-assisted dosimetric planning procedure which includes: i), an analytical stage for setting up the large volume via 2D and 3D displays; ii), a planning stage for issue of a treatment strategy including dosimetric simulations; and iii), a treatment stage to drive the target volume to the radiation unit isocenter. The combined use of stereotactic methods and multimodality imagery ensures spatial coherence and makes target definition and cognition of structure environment more accurate. The dosimetric planning suited to the spatial reference (the stereotactic frame) guarantees optimal distribution of the dose, computed by the original 3D volumetric algorithm. A computer-driven chair-framework cluster was designed to position the target volume at the radiation unit isocenter [fr

  13. Impact of Multileaf Collimator Configuration Parameters on the Dosimetric Accuracy of 6-MV Intensity-Modulated Radiation Therapy Treatment Plans.

    Science.gov (United States)

    Petersen, Nick; Perrin, David; Newhauser, Wayne; Zhang, Rui

    2017-01-01

    The purpose of this study was to evaluate the impact of selected configuration parameters that govern multileaf collimator (MLC) transmission and rounded leaf offset in a commercial treatment planning system (TPS) (Pinnacle 3 , Philips Medical Systems, Andover, MA, USA) on the accuracy of intensity-modulated radiation therapy (IMRT) dose calculation. The MLC leaf transmission factor was modified based on measurements made with ionization chambers. The table of parameters containing rounded-leaf-end offset values was modified by measuring the radiation field edge as a function of leaf bank position with an ionization chamber in a scanning water-tank dosimetry system and comparing the locations to those predicted by the TPS. The modified parameter values were validated by performing IMRT quality assurance (QA) measurements on 19 gantry-static IMRT plans. Planar dose measurements were performed with radiographic film and a diode array (MapCHECK2) and compared to TPS calculated dose distributions using default and modified configuration parameters. Based on measurements, the leaf transmission factor was changed from a default value of 0.001 to 0.005. Surprisingly, this modification resulted in a small but statistically significant worsening of IMRT QA gamma-index passing rate, which revealed that the overall dosimetric accuracy of the TPS depends on multiple configuration parameters in a manner that is coupled and not intuitive because of the commissioning protocol used in our clinic. The rounded leaf offset table had little room for improvement, with the average difference between the default and modified offset values being -0.2 ± 0.7 mm. While our results depend on the current clinical protocols, treatment unit and TPS used, the methodology used in this study is generally applicable. Different clinics could potentially obtain different results and improve their dosimetric accuracy using our approach.

  14. Impact of multileaf collimator configuration parameters on the dosimetric accuracy of 6-MV Intensity-Modulated radiation therapy treatment plans

    Directory of Open Access Journals (Sweden)

    Nick Petersen

    2017-01-01

    Full Text Available The purpose of this study was to evaluate the impact of selected configuration parameters that govern multileaf collimator (MLC transmission and rounded leaf offset in a commercial treatment planning system (TPS (Pinnacle3, Philips Medical Systems, Andover, MA, USA on the accuracy of intensity-modulated radiation therapy (IMRT dose calculation. The MLC leaf transmission factor was modified based on measurements made with ionization chambers. The table of parameters containing rounded-leaf-end offset values was modified by measuring the radiation field edge as a function of leaf bank position with an ionization chamber in a scanning water-tank dosimetry system and comparing the locations to those predicted by the TPS. The modified parameter values were validated by performing IMRT quality assurance (QA measurements on 19 gantry-static IMRT plans. Planar dose measurements were performed with radiographic film and a diode array (MapCHECK2 and compared to TPS calculated dose distributions using default and modified configuration parameters. Based on measurements, the leaf transmission factor was changed from a default value of 0.001 to 0.005. Surprisingly, this modification resulted in a small but statistically significant worsening of IMRT QA gamma-index passing rate, which revealed that the overall dosimetric accuracy of the TPS depends on multiple configuration parameters in a manner that is coupled and not intuitive because of the commissioning protocol used in our clinic. The rounded leaf offset table had little room for improvement, with the average difference between the default and modified offset values being −0.2 ± 0.7 mm. While our results depend on the current clinical protocols, treatment unit and TPS used, the methodology used in this study is generally applicable. Different clinics could potentially obtain different results and improve their dosimetric accuracy using our approach.

  15. SU-E-T-128: Dosimetric Characteristics of Gafchromic EBT3 Films for Megavoltage Photon and Proton Beams.

    Science.gov (United States)

    Hayashi, N; Kato, H; Yada, R; Matsunaga, T; Ehara, I; Adachi, Y

    2012-06-01

    Gafchromic film for quantitative analysis was renewed from EBT2 to EBT3 film in November 2011. The purpose of this study is to investigate the relevant characteristics of EBT3 film for its application in dosimetric verification for IMRT/VMAT or proton therapy. We investigated the characteristics of EBT3 film with comparison of previous EBT2 film. The experiments in this study composed two categories. At first, the photo spectroscopy for the irradiated film was compared between EBT2 and EBT3. The film 1 day after the irradiation was analyzed by a photo spectrometer (SR520: JASCO Corporation, Japan). Secondly, we investigated several calibration curves which obtained by same batch. The films were calibrated by irradiation the films to 13 dose steps. The irradiated films were scanned by a flatbed scanner (ES-10000XL, Epson-Seiko Corporation, Japan). The difference on scan orientation was evaluated alternate portrait and landscape directions. The photon and proton beams were delivered from Clinac 21EX (Varian) and Mitsubishi machine, respectively. The peak absorption wavelength of EBT3 film and its response at all active range were basically same with that of EBT2 film. The peak wavelength of photo absorption in EBT3 was observed at 585 and 634 nm. The fog optical density was increased due to the hazy matte polyester for active layer. However, there is no change the tendency of the calibration curve responding to megavoltage photon and proton beams. The scan orientation dependency of EBT3 film was observed with similar to EBT2 film. The optical density of portrait orientation was 10% higher than that of landscape orientation. The dosimetric characteristics of EBT3 film were basically same with EBT2 film. With regard to the matte polyester, the creation of Newton's rings during scanning procedure was reduced. However, the suitable scan protocol should be used for accurate film dosimetry. © 2012 American Association of Physicists in Medicine.

  16. A radioactive seed implant on a rabbit's liver following a voxel model representation for dosimetric proposals

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Tarcisio P.R.; Andrade, Joao Paulo Lopes de; Costa, Igor Temponi; Teixeira, Cleuza H. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares]. E-mail: campos@nuclear.ufmg

    2005-07-01

    Animal models have been used in experimentation with ionizing radiation. The evaluation of the energy absorbed per unit tissue mass in vivo transported by nuclear particles is a task to be performed before experimentation. Stochastic or deterministic methodology can be applied, however the dosimetric protocols applied in radiotherapy center cannot be applied directly due to the inherent small geometry and chemical composition of the animal distinct from human. The present article addresses a method in development that will predict the dose distribution into the rabbit thorax based on the solution of the transport phenomena in a voxel model. The model will be applied to simulate a seed implant experiment on a rabbit. Herein, the construction of the three-dimensional voxel model anthropomorphic -anthropometrics to the rabbit is presented. The model is assembling from a set of computer tomography of the rabbit. The computational phantom of the thorax starts at the digitalisation of the CT images, tissue definition, and color image representation of each tissue and organ. The chemical composition and mass density of each tissue is evaluated as similar date presented by ICRU-44. To treat the images, a code namely SISCODES, developed in house, was used. The in vivo experiment that will be simulated is also described. That is a implant of five seeds of 1.6x2 mm performed in a rabbit's liver. The perspective of this work is the application of the model in dosimetric studies predicting the dose distribution around the seed's implanted in vivo experiments. (author)

  17. SU-D-19A-07: Dosimetric Comparison of HDR Plesiotherapy and Electron Beam Therapy for Superficial Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A; Jacob, D; Andreou, K; Raben, A; Chen, H; Koprowski, C; Mourtada, F [Christiana Care Hospital, Newark, DE (United States)

    2014-06-01

    Purpose: Large superficial (skin, soft tissue sarcoma) lesions located on curved areas are hard to treat with electrons. The Freiburg Flap (Nucletron, Netherlands) is a flexible mesh style surface which can be easily shaped to fit curved surfaces for reproducible HDR fraction delivery. To understand the fundamental dosimetric differences, a dosimetric comparison was made between HDR plesiotherapy (Freiburg applicator for lesions over 4cm) and external electron beam radiotherapy over cases with varying target curvature (both stylized and clinical cases). Methods: Four stylized cases with variable complexity were created using artificial DICOM axial CT slices and RT structures (a square and three curved structures on a 4.5cm radius cylinder). They were planned using Oncentra v4.3 and exported to Pinnacle v9.6 for electrons planning. The HDR source dwell positions were optimized for the best coverage of the targets using graphical optimization. Electron treatment plans were created in Pinnacle using the same CT and RT structures of three HDR cases with surface lesions previously treated with the Freiburg flap. The En face electron plans used 6-12 MeV electrons and 0.5–1 cm bolus was added to increase surface dose. The electron plans were prescribed to an isodose line to conform to the target. Results: For all lesions, the average target dose coverage was similar (D90ave of 100% for HDR vs 101% for electrons). For lesions with high curvature, the HDR coverage was better (D90 102% vs D90 97% for electron). For all cases, adjacent structures high dose region was lower for HDR than electrons (D1cc 100% for HDR vs D1cc 111% for electrons). Conclusion: HDR plesiotherapy offers excellent target conformity for superficial targets similar to electrons. However, for lesions with complex curved surfaces, HDR has the advantage to achieve better dose distributions using graphical optimization to spare adjacent normal tissue while maximizing target coverage.

  18. Dosimetric impact of gastrointestinal air column in radiation treatment of pancreatic cancer.

    Science.gov (United States)

    Estabrook, Neil C; Corn, Jonathan B; Ewing, Marvene M; Cardenes, Higinia R; Das, Indra J

    2018-02-01

    Dosimetric evaluation of air column in gastrointestinal (GI) structures in intensity modulated radiation therapy (IMRT) of pancreatic cancer. Nine sequential patients were retrospectively chosen for dosimetric analysis of air column in the GI apparatus in pancreatic cancer using cone beam CT (CBCT). The four-dimensional CT (4DCT) was used for target and organs at risk (OARs) and non-coplanar IMRT was used for treatment. Once a week, these patients underwent CBCT for air filling, isocentre verification and dose calculations retrospectively. Abdominal air column variation was as great as ±80% between weekly CBCT and 4DCT. Even with such a large air column in the treatment path for pancreatic cancer, changes in anteroposterior dimension were minimal (2.8%). Using IMRT, variations in air column did not correlate dosimetrically with large changes in target volume. An average dosimetric deviation of mere -3.3% and a maximum of -5.5% was observed. CBCT revealed large air column in GI structures; however, its impact is minimal for target coverage. Because of the inherent advantage of segmentation in IMRT, where only a small fraction of a given beam passes through the air column, this technique might have an advantage over 3DCRT in treating upper GI malignancies where the daily air column can have significant impact. Advances in knowledge: Radiation treatment of pancreatic cancer has significant challenges due to positioning, imaging of soft tissues and variability of air column in bowels. The dosimetric impact of variable air column is retrospectively studied using CBCT. Even though, the volume of air column changes by ± 80%, its dosimetric impact in IMRT is minimum.

  19. Dosimetric effects of rotational offsets in stereotactic body radiation therapy (SBRT) for lung cancer

    International Nuclear Information System (INIS)

    Yang, Yun; Catalano, Suzanne; Kelsey, Chris R.; Yoo, David S.; Yin, Fang-Fang; Cai, Jing

    2014-01-01

    To quantitatively evaluate dosimetric effects of rotational offsets in stereotactic body radiation therapy (SBRT) for lung cancer. Overall, 11 lung SBRT patients (8 female and 3 male; mean age: 75.0 years) with medially located tumors were included. Treatment plans with simulated rotational offsets of 1°, 3°, and 5° in roll, yaw, and pitch were generated and compared with the original plans. Both clockwise and counterclockwise rotations were investigated. The following dosimetric metrics were quantitatively evaluated: planning target volume coverage (PTV V 100% ), max PTV dose (PTV D max ), percentage prescription dose to 0.35 cc of cord (cord D 0.35 cc ), percentage prescription dose to 0.35 cc and 5 cc of esophagus (esophagus D 0.35 cc and D 5 cc ), and volume of the lungs receiving at least 20 Gy (lung V 20 ). Statistical significance was tested using Wilcoxon signed rank test at the significance level of 0.05. Overall, small differences were found in all dosimetric matrices at all rotational offsets: 95.6% of differences were 100% , PTV D max , cord D 0.35 cc , esophagus D 0.35 cc , esophagus D 5 cc , and lung V 20 was − 8.36%, − 6.06%, 11.96%, 8.66%, 6.02%, and − 0.69%, respectively. No significant correlation was found between any dosimetric change and tumor-to-cord/esophagus distances (R 2 range: 0 to 0.44). Larger dosimetric changes and intersubject variations were observed at larger rotational offsets. Small dosimetric differences were found owing to rotational offsets up to 5° in lung SBRT for medially located tumors. Larger intersubject variations were observed at larger rotational offsets

  20. Simulation of The ICRP-30 Dosimetric Model for the Respiratory Tract

    International Nuclear Information System (INIS)

    Giaddui, T.; Atia, M. A.

    2004-01-01

    Matlab was used to write a simulation program (ACID1) to simulate the ICRP-30 dosimetric model for the respiratory tract. The program (a new version of the one presented at the sixth Arab conference held in Cairo 2002) calculates a series of dosimetric quantities for the reference man as a result of the inhalation of any radionuclide. The program also plots the variation of activity with time for all organs and provided with a graphical user interface to make it friendly user. The results obtained by this program was compared with similar results obtained by other source and found to be very close. (Authors)

  1. Dosimetric monitoring in Ukraine - present status and path to the future

    International Nuclear Information System (INIS)

    Chumak, V.; Boguslavskaya, A.

    2005-01-01

    Full text: Ukraine is the country which utilizes radiation in many peaceful areas. So, nuclear energy sector includes 15 power units (including two new units commissioned in 2004), nuclear fuel cycle also include uranium mines, radiation sources are widely used in industry, science and medicine. As a result, about 50,000 occupationally exposed workers require dosimetric monitoring. However, presently dosimetry services in Ukraine cover only about 38,000 occupationally exposed workers, including 9,100 medical professionals, 16,400 employees of 5 nuclear power plants and ca. 12,400 workers dealing with other sources of occupational exposure (industry, research). Territorial dosimetry services, responsible for dosimetric monitoring in industry and medicine operate in 13 of 25 oblasts (regions) of Ukraine. The coverage of critical groups by dosimetric monitoring is variable and ranges from 38 % to 100 % depending on the oblast. With rare exception, instrumentation is represented by outdated manual TLD systems (inaccurate and insufficiently sensitive) capable of measurement of deep photon dose only; no personal monitoring of beta and neutron exposure is possible now. Quality assurance is limited to the annual metrological attestation of the dosimetric instruments. No information exchange infrastructure and dosimetric registry are in place. The dosimetric data is stored in home-made data environments or even in paper log-books, no data on individual doses is conveyed to central depository, which could be easily accessible for regulating authorities. Although the standing law requires elaboration of the United System for monitoring and registration individual doses, little was done so far, mainly due to lack of domestic funding. However, intention is strong to build such network in accordance with the best practice, covering not only the aspects of physical measurement and data storage, but also quality assurance, accreditation programs and training of the local personnel

  2. Use of secondary phosphorescence for determination of the dose absorbed in dosimetric phosphors

    CERN Document Server

    Yaek, I V

    2002-01-01

    The measuring method of optically stimulated persistence (OSP) based on both the time division of the stimulating irradiation and luminescent response registration was applied for the radiation dosimetry. It was shown that the stimulation by the short-wave radiation crossing with spectrum of the dosimetric phosphor is possible. The spectrum of the stimulation of industry dosimetric phosphors was measured. The characteristics of the OSP registration for the phosphors which has manganese Mn sup 2 sup + as the activator is considered. Decay time of inner center luminescence is 40-50 ms. This method is used for the dosimetry of the natural quartzes to determine their age.

  3. Improvement in the dosimetric CaSO4: Dy obtention method

    International Nuclear Information System (INIS)

    Campos, L.L.; Frutuoso, P.H.; Souto, V.J.

    1989-08-01

    With the purpose of saving up in the dosimetric CaSO 4 : Dy production, a new method was developed to obtain single crystals. In this method the nitrogen flux used to carry the acid vapour was substituted by compressed air. It was compared all dosimetric properties of the crystals. There is no alteration in the glow curve. The sensitivity is the same in both cases and the lower detection limit is 3.8 x 10 -8 C.Kg -1 (150 μR) [pt

  4. Desarrollo humano y desarrollo turístico: el caso del cantón de Santa Cruz de Guanacaste

    Directory of Open Access Journals (Sweden)

    Luis Carlos Morales Zúñiga

    2011-01-01

    Full Text Available En este documento se analiza la relación existente entre crecimiento económico, generado por las actividades turísticas, y desarrollo humano en el cantón de Santa Cruz, Guanacaste. Se realiza un especial énfasis en el proceso de transformación de la estructura económica del cantón de Santa Cruz, desde una economía tradicional, hacia una economía de servicios, y su impacto en el desarrollo humano del cantón.

  5. SU-F-T-45: Dosimetric Effects of Saline Filled Balloons During IORT Using Xoft Electronic Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Redler, G; Templeton, A; Turian, J; Chu, J; Bernard, D; Zhen, H; Liao, Y [Rush University Medical Center, Chicago, IL (United States)

    2016-06-15

    Purpose: The portability of Xoft Axxent Electronic Brachytherapy (EBx) System has made it a viable option for intraoperative radiation therapy (IORT) treatment of early-stage breast cancer. The low energy (50kVp) of the X-ray source makes the shielding easy, but also means its dose distribution is sensitive to the medium’s composition. Current treatment planning systems (TPS) typically assume homogenous water for brachytherapy dose calculations, including the pre-calculated atlas plans for the Xoft IORT cases. However, Xoft recommends using saline to fill the balloon applicator. This study investigates the dosimetric difference due to the increased effective atomic number (Zeff) from water (7.42) to saline (7.56). Methods: The diameter of the balloon applicators ranges from 3–6cm, with 4cm being most frequently used. For the 4-cm and 6-cm diameter applicators, MCNP Monte Carlo program was used to calculate the dose at the surface (Ds) of the middle section of the balloon and 1 cm away (D1cm) for water- and saline-filled balloons: one plan with a single dwell at the center and another with multiple dwells as in the atlas plans. The single dwell plan is a simple estimation of the dosimetry, while the atlas plan is representative of the actual dose distribution. Results: The single-dwell plan showed a 5.1% and 6.1% decrease in Ds for the 4- and 6-cm applicators, respectively, due to the saline. The atlas plan showed similar Results: 4.8% and 6.4% decrease, respectively. The decrease in D1cm is 4.3%–5.2% and 3.3%–5.3s% in the single-dwell and atlas plans, respectively, for the 4- and 6-cm applicator. Conclusion: The dosimetric effect introduced by saline is on the order of 5%. This effect should be taken into account during both treatment planning and patient outcome studies.

  6. SU-E-T-10: A Dosimetric Comparison of Copper to Lead-Alloy Apertures for Electron Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Rusk, B; Hogstrom, K; Gibbons, J; Carver, R [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States)

    2014-06-01

    Purpose: To evaluate dosimetric differences of copper compared to conventional lead-alloy apertures for electron beam therapy. Methods: Copper apertures were manufactured by .decimal, Inc. and matching lead-alloy, Cerrobend, apertures were constructed for 32 square field sizes (2×2 – 20×20 cm{sup 2}) for five applicator sizes (6×6–25×25 cm{sup 2}). Percent depth-dose and off-axis-dose profiles were measured using an electron diode in water with copper and Cerrobend apertures for a subset of aperture sizes (6×6, 10×10, 25×25 cm{sup 2}) and energies (6, 12, 20 MeV). Dose outputs were measured for all field size-aperture combinations and available energies (6–20 MeV). Measurements were taken at 100 and 110 cm SSDs. Using this data, 2D planar absolute dose distributions were constructed and compared. Passing criteria were ±2% of maximum dose or 1-mm distance-to-agreement for 99% of points. Results: A gamma analysis of the beam dosimetry showed 93 of 96 aperture size, applicator, energy, and SSD combinations passed the 2%/1mm criteria. Failures were found for small field size-large applicator combinations at 20 MeV and 100-cm SSD. Copper apertures showed a decrease in bremsstrahlung production due to copper's lower atomic number compared to Cerrobend (greatest difference was 2.5% at 20 MeV). This effect was most prominent at the highest energies with large amounts of shielding material present (small field size-large applicator). Also, an increase in electrons scattered from the collimator edge of copper compared to Cerrobend resulted in an increased dose at the field edge for copper at shallow depths (greatest increase was 1% at 20 MeV). Conclusion: Apertures for field sizes ≥6×6 cm{sup 2} at any energy, or for small fields (≤4×4 cm{sup 2}) at energies <20 MeV, showed dosimetric differences less than 2%/1mm for more than 99% of points. All field size-applicator size-energy combinations passed 3%/1mm criteria for 100% of points. Work partially

  7. Evaluando la Facilidad de Aprendizaje de Frameworks mvc en el Desarrollo de Aplicaciones Web

    OpenAIRE

    Libardo Pantoja; César Pardo

    2016-01-01

    Uno de los aspectos relevantes al momento de elegir un framework de desarrollo de software es de- terminar la curva de aprendizaje que requiere. En los proyectos de desarrollo de software, en general, los desarrolladores disponen de poco tiempo para entregar un producto estable y usualmente requieren de frameworks de desarrollo que tengan una curva de aprendizaje baja. Actualmente, existen diversos frameworks para soportar el desarrollo web; sin embargo, elegir el más adecuado puede ser una t...

  8. A dosimetric selectivity intercomparison of HDR brachytherapy, IMRT and helical tomotherapy in prostate cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Coucke, Philippe [Dept. of Radiation Oncology, Liege Univ. Hospital (Belgium); Lenaerts, Eric [Dept. of Medical Physics, Liege Univ. Hospital (Belgium); De Patoul, Nathalie; Vynckier, Stefaan [Dept. of Medical Physics, St Luc Univ. Hospital, Brussels (Belgium); Scalliet, Pierre [Dept. of Radiation Oncology, St Luc Univ. Hospital, Brussels (Belgium); Nickers, Philippe [Dept. of Radiation Oncology, Oscar Lambret Center, Lille (France)

    2009-11-15

    Background and purpose: dose escalation in order to improve the biochemical control in prostate cancer requires the application of irradiation techniques with high conformality. The dosimetric selectivity of three radiation modalities is compared: high-dose-rate brachytherapy (HDR-BT), intensity-modulated radiation radiotherapy (IMRT), and helical tomotherapy (HT). Patients and methods: ten patients with prostate adenocarcinoma treated by a 10-Gy HDR-BT boost after external-beam radiotherapy were investigated. For each patient, HDR-BT, IMRT and HT theoretical treatment plans were realized using common contour sets. A 10-Gy dose was prescribed to the planning target volume (PTV). The PTVs and critical organs' dose-volume histograms obtained were compared using Student's t-test. Results: HDR-BT delivers spontaneously higher mean doses to the PTV with smaller cold spots compared to IMRT and HT. 33% of the rectal volume received a mean HDR-BT dose of 3.86 {+-} 0.3 Gy in comparison with a mean IMRT dose of 6.57 {+-} 0.68 Gy and a mean HT dose of 5.58 {+-} 0.71 Gy (p < 0.0001). HDR-BT also enables to better spare the bladder. The hot spots inside the urethra are greater with HDR-BT. The volume of healthy tissue receiving 10% of the prescribed dose is reduced at least by a factor of 8 with HDR-BT (p < 0.0001). Conclusion: HDR-BT offers better conformality in comparison with HT and IMRT and reduces the volume of healthy tissue receiving a low dose. (orig.)

  9. Thermoluminescent dosimetric properties of CaF{sub 2}:Tm produced by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, D.A.A. de; Khoury, H.J.; Asfora, V.K.; Barros, V.S.M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Oliveira, R.A.P. [Universidade Federal do Vale do Sao Francisco (IPCM/UNIVASF), Juazeiro, BA (Brazil). Instituto de Pesquisa em Ciencias dos Materiais. Departamento de Energia Nuclear

    2015-07-01

    Calcium Fluoride is one of the oldest known thermoluminescent materials and is considered to be one of the most sensitive. In particular for thulium doped CaF{sub 2}, since it was introduced in 1977 by Lucas and Kapsar, besides gamma radiation dosimetry, there have been several attempts for its use in application involving mixed radiation fields (ex.: neutron and gamma; alpha and beta), low energy photons, π- dosimetry and neutrino detection. Research for novel improved methods of fabrication are ongoing. This work presents the dosimetric properties results of CaF{sub 2}:Tm produced by combustion synthesis. The X-ray diffraction (Brucker D2 Phaser) confirmed that CaF{sub 2} was successfully produced. Samples were irradiated in a Co-60 (Gammacell 220 Nordion) and Cs-137 (STS/OB-85) gamma sources for high and low doses, respectively. TL emission spectra, obtained using a Hammamatsu optical spectrometer, has the same lines of commercial CaF{sub 2}:Tm, although transitions {sup 3}P{sub 0} → {sup 3}F{sub 4} (455 nm) and {sup 1}G{sub 4}→ {sup 3}H{sub 6} (482 nm) are shown to be proportionally more intense. The dose response lower limit is in the range of 100 μGy. Thermoluminescence glow curves were obtained in a Harshaw 3500 TL reader. The deconvolution technique was employed and seven glow peaks were found as well as its kinetic parameters, similar to the commercial CaF{sub 2}:Tm. A linear dose response curve was obtained for the range 0.1 mGy to 50 Gy, with the onset of a supralinear behavior at 50 Gy up to 100 Gy. The minimum measurable dose for gamma (Cs- 137) was around 100 μGy for a 6.0 mm diameter by 1.0 mm in thickness pellet. Variation of the dose response due to fading was within 6% in 60 days. (author)

  10. Theoretical and experimental determination of dosimetric characteristics for ADVANTAGETM Pd-103 brachytherapy source

    International Nuclear Information System (INIS)

    Meigooni, Ali S.; Dini, Sharifeh A.; Awan, Shahid B.; Dou, Kai; Koona, Rafiq A.

    2006-01-01

    ADVANTAGE TM Pd-103 brachytherapy source has been recently introduced by IsoAid TM for prostate permanent implants. Dosimetric characteristics (Dose rate constant, radial dose function, 2D-, and 1D-anisotropy functions) of this source model have been determined using both theoretical and experimental methods, following the updated TG-43U1 protocol. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with the 1999 Standards. Measurements were performed in Solid Water TM using LiF TLD chips and the theoretical calculations were performed in Solid Water TM and liquid water phantom materials using PTRAN Monte Carlo code. The results of the Monte Carlo simulation have shown a dose rate constant of 0.69 cGy h -1 U -1 in liquid water and 0.67 cGy h -1 U -1 in Solid Water TM medium. The measured dose rate constant in Solid Water TM was found to be 0.68±8% cGy h -1 U -1 , which is in a good agreement (within ±5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE TM Pd-103 source were calculated for radial distances ranging from 0.5 to 5.0 cm. Radial dose function was determined for radial distances ranging from 0.2 to 8.0 cm using line source approximation. All these calculations are based on L eff equal to 3.61 cm, calculated following TG-43U1 recommendations. The tabulated data for 2D-anisotropy function, 1D-anisotropy function, dose rate constant and radial dose function have been produced for clinical application of this source model

  11. Theoretical and experimental determination of dosimetric characteristics for ADVANTAGE{sup TM} Pd-103 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Meigooni, Ali S. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)]. E-mail: alimeig@uky.edu; Dini, Sharifeh A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Awan, Shahid B. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Dou, Kai [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Koona, Rafiq A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)

    2006-08-15

    ADVANTAGE{sup TM} Pd-103 brachytherapy source has been recently introduced by IsoAid{sup TM} for prostate permanent implants. Dosimetric characteristics (Dose rate constant, radial dose function, 2D-, and 1D-anisotropy functions) of this source model have been determined using both theoretical and experimental methods, following the updated TG-43U1 protocol. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with the 1999 Standards. Measurements were performed in Solid Water{sup TM} using LiF TLD chips and the theoretical calculations were performed in Solid Water{sup TM} and liquid water phantom materials using PTRAN Monte Carlo code. The results of the Monte Carlo simulation have shown a dose rate constant of 0.69 cGy h{sup -1} U{sup -1} in liquid water and 0.67 cGy h{sup -1} U{sup -1} in Solid Water{sup TM} medium. The measured dose rate constant in Solid Water{sup TM} was found to be 0.68{+-}8% cGy h{sup -1} U{sup -1}, which is in a good agreement (within {+-}5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE{sup TM} Pd-103 source were calculated for radial distances ranging from 0.5 to 5.0 cm. Radial dose function was determined for radial distances ranging from 0.2 to 8.0 cm using line source approximation. All these calculations are based on L {sub eff} equal to 3.61 cm, calculated following TG-43U1 recommendations. The tabulated data for 2D-anisotropy function, 1D-anisotropy function, dose rate constant and radial dose function have been produced for clinical application of this source model.

  12. SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy

    International Nuclear Information System (INIS)

    Tse, K; Morley, L; Cashell, A; Sperduti, A; McQuestion, M; Chow, J

    2016-01-01

    Purpose: This study investigated the superficial dose enhancement in the application of topical agents, clinical materials (thermal mask and bolus) and dressings in megavoltage photon beam radiotherapy. Different topical skin agents, clinical materials and dressings were evaluated and compared for their skin dosimetric impacts on the patients during radiation treatment. Methods: Superficial dose enhancements, or percentage doses with and without the studying materials, were measured using the 6 MV (Field size = 10×10 cm"2) photon beams produced by a Varian TrueBeam linear accelerator. Twelve topical agents, five dressings (dry and wet conditions) and three clinical materials were studied. A solid water phantom was used with a MOSFET dose detector (TN-1002RD, Thomson and Nielsen Electronic, Ottawa, Ontario, Canada) located under a 1-mm PMMA slab to measure the skin dose. The distance between the radiation source and phantom surface was set to 100 cm in all measurements. The topical agents were distributed evenly with 1.5 mm thickness using our specific sample holder on the phantom surface. Extrapolations were made of 0.5 mm thickness for the agents to provide meaningful clinical value. Results: By comparing surface doses without studying materials, it is found that no topical agents had superficial dose enhancement higher than the clinical materials namely, thermoplastic mask (128%), 5-mm Superflab™ bolus (158%) and 10-mm Superflab™ bolus (171%) regarding the same thickness. Superficial dose enhancement of dry dressing did not exceed 110.5%, while wet dressings produced higher dose enhancements (133% for wet Mepilex lite and 141% for wet Mepilex Ag transfer). Conclusion: It is concluded that the evaluated topical agents and dry dressings did not increase the superficial dose to a concerning level, even using excessive thickness in every fraction of radiation treatment. Wet dressings were found producing the bolus effect, but was still substantially less than

  13. SU-F-T-379: Dosimetric Impacts of Topical Agents and Dressings On Skin in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Tse, K; Morley, L; Cashell, A; Sperduti, A; McQuestion, M; Chow, J [Princess Margaret Cancer Centre, Toronto, ON (Canada)

    2016-06-15

    Purpose: This study investigated the superficial dose enhancement in the application of topical agents, clinical materials (thermal mask and bolus) and dressings in megavoltage photon beam radiotherapy. Different topical skin agents, clinical materials and dressings were evaluated and compared for their skin dosimetric impacts on the patients during radiation treatment. Methods: Superficial dose enhancements, or percentage doses with and without the studying materials, were measured using the 6 MV (Field size = 10×10 cm{sup 2}) photon beams produced by a Varian TrueBeam linear accelerator. Twelve topical agents, five dressings (dry and wet conditions) and three clinical materials were studied. A solid water phantom was used with a MOSFET dose detector (TN-1002RD, Thomson and Nielsen Electronic, Ottawa, Ontario, Canada) located under a 1-mm PMMA slab to measure the skin dose. The distance between the radiation source and phantom surface was set to 100 cm in all measurements. The topical agents were distributed evenly with 1.5 mm thickness using our specific sample holder on the phantom surface. Extrapolations were made of 0.5 mm thickness for the agents to provide meaningful clinical value. Results: By comparing surface doses without studying materials, it is found that no topical agents had superficial dose enhancement higher than the clinical materials namely, thermoplastic mask (128%), 5-mm Superflab™ bolus (158%) and 10-mm Superflab™ bolus (171%) regarding the same thickness. Superficial dose enhancement of dry dressing did not exceed 110.5%, while wet dressings produced higher dose enhancements (133% for wet Mepilex lite and 141% for wet Mepilex Ag transfer). Conclusion: It is concluded that the evaluated topical agents and dry dressings did not increase the superficial dose to a concerning level, even using excessive thickness in every fraction of radiation treatment. Wet dressings were found producing the bolus effect, but was still substantially less

  14. Dosimetric characteristics of a reusable 3D radiochromic dosimetry material.

    Directory of Open Access Journals (Sweden)

    Jong Min Park

    Full Text Available To investigate the dosimetric characteristics of PRESAGEREU dosimeters.Commercially available PRESAGEREU dosimeters (size of 10 mm × 10 mm × 45 mm were divided into two groups, with one of the groups placed at room temperature of 22°C (RT group and another group placed at low temperature of 10°C (LT group. A total of 3 dosimeters (set of dosimeters were irradiated at a time, with doses of 1 Gy, 2 Gy, 4 Gy, 8 Gy, 12 Gy, 16 Gy, and 20 Gy, at a nominal dose rate of 400 MU/min at temperature of 22°C. The dosimeters were irradiated three additional times by delivering the same doses as those during the initial irradiations (4 irradiation cycles. Optical density (OD was assessed using optical CT scanning.Considering both linearity and sensitivity of the OD curves, R2 above 0.95 and sensitivity above 0.04 ΔOD/Gy were observed at the 1st irradiation (reading time ≤ 6 h and 2nd irradiation (reading time = 0.5 h for the RT group. For the LT group, those values were observed at the 1st irradiation (reading time ≤ 2 h, and the 3rd and 4th irradiations (both reading times = 0.5 h. Considering the reproducibility of signals in response to the same dose, dosimeters in the RT group showed average deviations among dosimeters less than 5% (the 1st and 2nd irradiations at the reading time of 0.5 h, while for dosimeters in the LT group showed average deviations among dosimeters less than 6% (the 3rd and 4th irradiations at the reading time of 0.5 h. For the rest, the OD curves were not linear, sensitivities of the dosimeters were lower than 0.04 ΔOD/Gy, and OD deviations at the same dose were larger than 6%.At room temperature, PRESAGEREU dosimeters could be used for dose measurement only for up to two dose measurement sessions. At low temperatures, usage of PRESAGEREU dosimeters for dose measurement seems to be possible from the 3rd irradiation. When reusing PRESAGEREU dosimeters, the OD curve should be re-defined for every measurement session because

  15. Dosimetric accuracy of Kodak EDR2 film for IMRT verifications.

    Science.gov (United States)

    Childress, Nathan L; Salehpour, Mohammad; Dong, Lei; Bloch, Charles; White, R Allen; Rosen, Isaac I

    2005-02-01

    Patient-specific intensity-modulated radiotherapy (IMRT) verifications require an accurate two-dimensional dosimeter that is not labor-intensive. We assessed the precision and reproducibility of film calibrations over time, measured the elemental composition of the film, measured the intermittency effect, and measured the dosimetric accuracy and reproducibility of calibrated Kodak EDR2 film for single-beam verifications in a solid water phantom and for full-plan verifications in a Rexolite phantom. Repeated measurements of the film sensitometric curve in a single experiment yielded overall uncertainties in dose of 2.1% local and 0.8% relative to 300 cGy. 547 film calibrations over an 18-month period, exposed to a range of doses from 0 to a maximum of 240 MU or 360 MU and using 6 MV or 18 MV energies, had optical density (OD) standard deviations that were 7%-15% of their average values. This indicates that daily film calibrations are essential when EDR2 film is used to obtain absolute dose results. An elemental analysis of EDR2 film revealed that it contains 60% as much silver and 20% as much bromine as Kodak XV2 film. EDR2 film also has an unusual 1.69:1 silver:halide molar ratio, compared with the XV2 film's 1.02:1 ratio, which may affect its chemical reactions. To test EDR2's intermittency effect, the OD generated by a single 300 MU exposure was compared to the ODs generated by exposing the film 1 MU, 2 MU, and 4 MU at a time to a total of 300 MU. An ion chamber recorded the relative dose of all intermittency measurements to account for machine output variations. Using small MU bursts to expose the film resulted in delivery times of 4 to 14 minutes and lowered the film's OD by approximately 2% for both 6 and 18 MV beams. This effect may result in EDR2 film underestimating absolute doses for patient verifications that require long delivery times. After using a calibration to convert EDR2 film's OD to dose values, film measurements agreed within 2% relative

  16. Dosimetric measurements of Onyx embolization material for stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Roberts, Donald A.; Balter, James M.; Chaudhary, Neeraj; Gemmete, Joseph J.; Pandey, Aditya S.

    2012-01-01

    Purpose: Arteriovenous malformations are often treated with a combination of embolization and stereotactic radiosurgery. Concern has been expressed in the past regarding the dosimetric properties of materials used in embolization and the effects that the introduction of these materials into the brain may have on the quality of the radiosurgery plan. To quantify these effects, the authors have taken large volumes of Onyx 34 and Onyx 18 (ethylene-vinyl alcohol copolymer doped with tantalum) and measured the attenuation and interface effects of these embolization materials. Methods: The manufacturer provided large cured volumes (∼28 cc) of both Onyx materials. These samples were 8.5 cm in diameter with a nominal thickness of 5 mm. The samples were placed on a block tray above a stack of solid water with an Attix chamber at a depth of 5 cm within the stack. The Attix chamber was used to measure the attenuation. These measurements were made for both 6 and 16 MV beams. Placing the sample directly on the solid water stack and varying the thickness of solid water between the sample and the Attix chamber measured the interface effects. The computed tomography (CT) numbers for bulk material were measured in a phantom using a wide bore CT scanner. Results: The transmission through the Onyx materials relative to solid water was approximately 98% and 97% for 16 and 6 MV beams, respectively. The interface effect shows an enhancement of approximately 2% and 1% downstream for 16 and 6 MV beams. CT numbers of approximately 2600–3000 were measured for both materials, which corresponded to an apparent relative electron density (RED) ρ e w to water of approximately 2.7–2.9 if calculated from the commissioning data of the CT scanner. Conclusions: We performed direct measurements of attenuation and interface effects of Onyx 34 and Onyx 18 embolization materials with large samples. The introduction of embolization materials affects the dose distribution of a MV therapeutic beam

  17. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sasha.senthi@petermac.org [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Gill, Suki S. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Haworth, Annette; Kron, Tomas; Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Rolfo, Aldo [Radiation Therapy Services, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Thomas, Jessica [Biostatistics and Clinical Trials, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Duchesne, Gillian M. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Hamilton, Christopher H.; Joon, Daryl Lim [Radiation Oncology Department, Austin Repatriation Hospital, Heidelberg, VIC (Australia); Bowden, Patrick [Radiation Oncology Department, Tattersall' s Cancer Center, East Melbourne, VIC (Australia); Foroudi, Farshad [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia)

    2012-02-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V{sub 95%} and V{sub 100%}, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V{sub 95%}, PTV sigma index, and conformity number. The mean PTV V{sub 95%} was 92.5% (95% confidence interval, 91.3-93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90-2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76-0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p < .0001). The planning system independently influenced homogeneity (p = .038) and conformity (p = .021). The treatment date independently influenced the PTV V{sub 95%} only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures

  18. Dosimetric quality control in radiotherapy using TLD methodology

    International Nuclear Information System (INIS)

    Saravi, M.C.; Kessler, C.; Alvarez, P.E.; Feld, D.B.

    2002-01-01

    In the frame of the IAEA Co-ordinated Research Project 'Development of a Quality Assurance Program for Radiation Therapy Dosimetry in Developing Countries' a Dosimetric Quality Control Group was set up in Argentina in 1996, to develop a program in order to improve radiotherapy in the country. Nowadays, this Group, briefly called External Audit Group (EAG), is composed by the national Secondary Standard Dosimetry Laboratory (SSDL), which has the responsibility for dose determinations, traceability to international dosimetry chain and TLD measurements, and two Medical Physicists from CNEA who are working at the Oncology Hospital 'Marie Curie' in Buenos Aires. The present paper reports the activities performed by the EAG with external high energy photon beams in reference conditions and the results of two pilot studies on cobalt 60 beams in non-reference conditions. The first step of the program was to update the existing data base about the radiotherapy centres operating in the country. A form was sent to each of them in order to obtain basic information about their staff, number and type of treatment machines, brachytherapy sources, measuring devices, beam calibration, treatment planning system, simulator and other relevant data. 90 radiotherapy centres were registered in the EAG data base. Forms were completed by 75/90 centres. There are nowadays 69 cobalt 60 units and 42 LINACs operating in the country (18/42 LINACs producing high energy X ray and electron beams). EAG deals with measurements performed with mailed TLD irradiated at radiotherapy centres. Internal quality control on our TLD system is made during each audit by means of reference capsules irradiated by IAEA; external controls consist in blind tests performed by IAEA once a year. The correction factor, K en , determined at our SSDL for high energy X-rays was checked with the collaboration of IAEA and Prague National Radiation Protection Institute (PNRPI) by means of a blind test. Results for 4 MV, 6 MV

  19. Study of the dosimetric properties using organometallic polymers in solution

    International Nuclear Information System (INIS)

    Fernandes, David Moreira

    2012-01-01

    This work aimed to study the dosimetric characteristics of the polymer of the polymer ''poly-[ 1, l-bis (ethynyl) -4,4-biphenyl (bis-tributylphosphine) Pt (11)]'' (Pt-DEBP) compared to radiation gamma. The Pt-DEBP polymer, containing ten monomer units, was then dissolved in organic solvents as chloroform and toluene. The samples were irradiated at four concentrations (0.0500, 0.0375, 0.0250, 0.0113 mg / mL) in duplicate, with radiation doses ranging from 1 to 90 Gy. The results were evaluated based on spectroscopic techniques such as optical absorption spectroscopy (UV -Vis), fluorescence (emission), time resolved fluorescence (FRT) and Fourier transform infrared (FTIR). For DEBP-Pt solutions in chloroform, there is a shift in the position of the main optical absorption band (πt - π*) to lower wavelength (blue-shift), allied to a decreasing absorption intensity with increasing radiation dose. In fluorescence spectroscopy, there was a shift to longer wavelengths (redshift) allied to an increasing emission intensity with increasing radiation dose. FRT experiments on irradiated samples dissolved in chloroform indicated the presence of a new emitter center. FTIR spectra show the incorporation of chlorine in the polymer chain, justifying the blue-shift observed in the absorption spectra and the new emission center. In addition, the behavior of linear results in the absorption and fluorescence studies was investigated based on the relationship between the wavelength of maximum absorption/emission and the radiation dose. For both cases, a linear behavior was observed in relation to the sample concentration. Repeatability and stability tests were also performed. For the samples dissolved in toluene, there was no significant shift of the spectrum of absorption or fluorescence for all doses. The results show that the Pt-DEBP polymer dissolved in chloroform can be used as a dosimeter for x-ray doses between 1 - 30 Gy based on the changes in absorption and/or emission

  20. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    International Nuclear Information System (INIS)

    Senthi, Sashendra; Gill, Suki S.; Haworth, Annette; Kron, Tomas; Cramb, Jim; Rolfo, Aldo; Thomas, Jessica; Duchesne, Gillian M.; Hamilton, Christopher H.; Joon, Daryl Lim; Bowden, Patrick; Foroudi, Farshad

    2012-01-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V 95% and V 100% , respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V 95% , PTV sigma index, and conformity number. The mean PTV V 95% was 92.5% (95% confidence interval, 91.3–93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90–2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76–0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p 95% only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures of coverage, homogeneity, and conformity for the treatment of prostate cancer using IMRT. The differences seen between centers and planning systems and the coverage

  1. Quantitative dosimetric verification of an IMRT planning and delivery system

    International Nuclear Information System (INIS)

    Low, D.A.; Mutic, S.; Dempsey, J.F.; Gerber, R.L.; Bosch, W.R.; Perez, C.A.; Purdy, J.A.

    1998-01-01

    Background and purpose: The accuracy of dose calculation and delivery of a commercial serial tomotherapy treatment planning and delivery system (Peacock, NOMOS Corporation) was experimentally determined. Materials and methods: External beam fluence distributions were optimized and delivered to test treatment plan target volumes, including three with cylindrical targets with diameters ranging from 2.0 to 6.2 cm and lengths of 0.9 through 4.8 cm, one using three cylindrical targets and two using C-shaped targets surrounding a critical structure, each with different dose distribution optimization criteria. Computer overlays of film-measured and calculated planar dose distributions were used to assess the dose calculation and delivery spatial accuracy. A 0.125 cm 3 ionization chamber was used to conduct absolute point dosimetry verification. Thermoluminescent dosimetry chips, a small-volume ionization chamber and radiochromic film were used as independent checks of the ion chamber measurements. Results: Spatial localization accuracy was found to be better than ±2.0 mm in the transverse axes (with one exception of 3.0 mm) and ±1.5 mm in the longitudinal axis. Dosimetric verification using single slice delivery versions of the plans showed that the relative dose distribution was accurate to ±2% within and outside the target volumes (in high dose and low dose gradient regions) with a mean and standard deviation for all points of -0.05% and 1.1%, respectively. The absolute dose per monitor unit was found to vary by ±3.5% of the mean value due to the lack of consideration for leakage radiation and the limited scattered radiation integration in the dose calculation algorithm. To deliver the prescribed dose, adjustment of the monitor units by the measured ratio would be required. Conclusions: The treatment planning and delivery system offered suitably accurate spatial registration and dose delivery of serial tomotherapy generated dose distributions. The quantitative dose

  2. Descentralización, gobernanza y desarrollo local

    NARCIS (Netherlands)

    Brenner, L.; Lindert, P.H.C.M. van; Verkoren, O.

    2012-01-01

    Los artículos que forman parte de este número fueron originalmente presentados durante el 53º Congreso Internacional de Americanistas en México DF (19-24 de julio, 2009) en el seminario “Descentralización, Gobernabilidad y Desarrollo Local; Nuevas Perspectivas de América Latina”. Durante el

  3. Una taxonomía de modelos de desarrollo sustentable

    Directory of Open Access Journals (Sweden)

    Darcy Tetreault

    2004-01-01

    Full Text Available Este ensayo pretende ayudar a desenmarañar una parte del discurso sobre desarrollo sustentable mediante la construcción de una taxonomía de modelos de desarrollo sustentable. La misma taxonomía se basa en una revisión literaria extensiva que en cierta medida privilegia la experiencia mexicana. De este modo, el ensayo presenta y compara tanto modelos normativos como positivos. Los modelos incluidos son el modelo dominante, el cual corresponde con la estrategia esbozada en el Informe Bruntland y Agenda 21; la ecología política, un modelo desarrollado por el economista francés Alain Lipietz; el modelo comunitario de desarrollo sustentable, cuyas raíces se encuentran en una escuela de pensamiento de la década de los setenta conocida como el “otro desarrollo”; el comercio justo, una experiencia cuyas raíces se encuentran en las comunidades indígenas de Oaxaca; la producción forestal industrial comunitaria, que ha sido puesta en práctica por varias comunidades forestales en el sur y el centro del país; el activismo ambiental, sobre todo respecto a los con- fl ictos locales que giran en torno al control de los recursos naturales; y la conservación basada en la comunidad, cuya manifestación principal es la reserva de la biosfera

  4. La dimensión cultural como catalizadora del desarrollo

    OpenAIRE

    Duque Escobar, Gonzalo

    2011-01-01

    Cuando se enuncia el desarrollo sostenible, se expresa en términos de tres pilares: el ecológico, el social y el económico, por lo que la cultura como campo que abarca a la ciencia, donde naturaleza y sociedad son variables culturales con relaciones dialécticas, siempre ha escapado.

  5. De eufemismos y fetiches. Repensando el desarrollo, explorando el posdesarrollo

    Directory of Open Access Journals (Sweden)

    Juan Masullo Jiménez

    2012-01-01

    lo que yace en el fondo de la discusión es una preocupación por el bienestar de los pueblos del llamado Tercer Mundo, aquellos que, siendo objeto de diversas tecnologías políticas, han sido re-subjetivizados como necesitados de desarrollo.

  6. Desarrollo humano sostenible en la provincia de Palencia

    OpenAIRE

    Egido Pérez, María Nieves del

    2014-01-01

    El presente trabajo pretende hacer un estudio estadístico de la provincia de Palencia, conforme al índice de desarrollo humano sostenible con el análisis de las variables que componen el IDH –Salud, educación y renta- Grado en Relaciones Laborales y Recursos Humanos

  7. Esbozo general del desarrollo empresarial Colombiano durante el siglo XIX

    Directory of Open Access Journals (Sweden)

    Alvaro Morales Ordosgoitia

    1991-05-01

    Full Text Available RESUMEN El tema anunciado constituye básicamente en una síntesis muy apretada acerca de algunos aspectos que en la historia nacional del siglo XIX tuvieron que ver con el impulso y desarrollo de las primeras empresas colombianas.

  8. Informática: ¿desarrollo o perversión ?

    Directory of Open Access Journals (Sweden)

    Orlando Farray Álvarez

    2011-03-01

    Full Text Available La implantación de la computación y la informática en todos los sectores de la vida y la economía ha posibilitadouna época de nueva revolución industrial imponiendo grandes cambios tecnológicos así como maneras depensar y actuar de las personas. Esto hace que las universidades cubanas varíen la forma de preparar a susprofesionales acorde con las exigencias actuales y enfrentando todos los riesgos con lo que se han de chocar demodo que se utilicen dichos avances de la informatización en beneficio y desarrollo de la sociedad, rechazandotodo lo que sea perversión y obscenidad. Para lograr eso tiene que haber una ética que trace el camino correctoy defina poderosas herramientas de trabajo con las cuales se logre desarrollo y no perversión, pero un usoincorrecto de la misma puede favorecer lo contrario, por tanto, en este momento de grandes cambios tecnológicoscabe preguntarse: Informática ¿es desarrollo o perversión?  The installation of the computer science in all sectors of life and economy facilitates a time of new industrialrevolution imposing big technological changes. As well as the ways in which people think and net. This makesour universities vary the form of preparing their professionals to the current demands facing all the risks that theymust so that it is used in these the advances of the in the computer application in benefit and development of thesociety, rejecting all perversion and obscenity this there should be an ethics that traces the correct was anddefine powerful word tools. Is achieved with development and not perversion, but it's incorrect use of can favorresult. Therefore at present big technological changes are necessary to wonder about Computer science: it isdelopment or perversion?

  9. Effect of XCOM photoelectric cross-sections on dosimetric quantities calculated with EGSnrc

    International Nuclear Information System (INIS)

    Hobeila, F.; Seuntjens, J.P.

    2002-01-01

    The EGSnrc Monte-Carlo code system incorporates improved low energy photon physics such as atomic relaxations and the implementation of bound Compton cross-sections using the impulse approximation. The total cross-section for photoelectric absorption however, still relies on the data by Storm and Israel (S and I). Yet, low energy applications such as brachytherapy (e.g. 125 I) require up-to-date low-energy photoelectric cross-section data. In this paper, we study the dosimetric effects of a simple implementation of NIST XCOM-based photoelectric cross-sections in EGSnrc. This is done by calculating mass energy-absorption coefficients, absorbed dose from point sources, kilovoltage x-ray beams and ion chamber response. In the EGS code system, the PEGS4 routine reads the photoelectric and pair cross-sections for elements from a file (pgspepr.dat) and provides numerical fits for compounds which will be used by EGSnrc. We updated the photoelectric cross-sections of the pgspepr.dat file with the XCOM total photoelectric absorption cross-sections from NIST. After validation of this new implementation, we studied its effects on a number of dosimetrically relevant quantities. Firstly, we calculated mass energy-absorption coefficients by scoring energy transferred in a thin slab of water and air using the DOSRZnrc user code. Secondly, we calculated inverse-square corrected absorbed dose distributions from point sources in water by using an internally developed user code, KERNELph. Thirdly, we studied the differences in free-air ion chamber response calculations. Ion chamber response is defined as the dose to the cavity of an ionization chamber, D gas , positioned with its effective point of measurement at a reference point divided by air-kerma measured free-in-air at the same point. The ion chamber response was calculated using monoenergetic photon beams of energy 10 keV to 200 keV. The comparison of the Storm and Israel photoelectric cross-sections with the XCOM cross

  10. Cancer of the uterine cervix: dosimetric guidelines for prevention of late rectal and rectosigmoid complications as a result of radiotherapeutic treatment

    International Nuclear Information System (INIS)

    Pourquier, H.; Dubois, J.B.; Delard, R.

    1982-01-01

    This paper is the report of a dosimetric study of 41 rectal and rectosigmoid complications after radiotherapeutic treatment (1974-1978) of 287 cervical uterine tumors. Treatment consisted of external irradiation (25 MeV linear accelerator) and intracavitary irradiation (Fletcher-Suit applicator) at different doses depending on tumor stage. Dosimetric measurements were expressed as the maximum rectal dose and mean rectal dose on the anterior surface of the rectum, as proposed by the Groupe Europeen de Curietherapie. Rectal doses were also studied as a function of intracavitary irradiation and intracavitary + external irradiation (maximum rectal and mean cummulative doses for each). The results show a significant difference in the state of the patients with and without complications, based on the dose reaching the rectum. The maximum and the mean cumulative rectal doses serve as one of the primary indicators for predicting complications. These values should therefore be determined before placement of intracavitary sources or, at the latest, before the second intracavitary applications. We have shown that there is no fixed threshold dose, but that it varies from one region to another, depending on level of external irradiation. Our results argue in favor of adapting individual patient therapy based on simple precautions, which are adjustable to all treatment modalities. This method could lead to complete elimination of late rectal and rectosigmoid complications arising from radiotherapeutic treatment of cervical uterine cancer

  11. Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology; Comportamiento dosimetrico de dosimetros termoluminiscentes a bajas dosis en radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Ramirez R, G. [Hospital Juarez de Mexico, Av. IPN 5160, Col. Magdalena de las Salinas, 07760 Mexico D. F. (Mexico); Gaona, E., E-mail: susi2489@hotmail.com [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO{sub 4}: Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO{sub 4}: Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO{sub 4}: Dy). (Author)

  12. Más alla del concepto: desarrollo sostenible

    Directory of Open Access Journals (Sweden)

    Laura Benavides López

    2013-05-01

    Full Text Available El artículo tiene la finalidad de promover la reflexión con respecto al desarrollo sostenible, como un marco de referencia para el educador, que le permita comprender la Década de la Educación para el Desarrollo Sostenible y la Declaratoria Paz con Naturaleza.  La autora describe y reflexiona sobre el concepto, desde una perspectiva basada en la alteridad; por lo tanto, parte de una posición ética donde se potencializa a la persona para que sea constructora del desarrollo sostenible que requiere el país, donde la educación, la justicia social y la democracia conforman la plataforma para el logro de este. Se señalan aspectos fundamentales, como cuál fue el origen de desarrollo sostenible y como está idea se fue encuadrando dentro de una nueva ética centrada en la gente y para la gente. Se parte de que el desarrollo sostenible es un proceso de cambio y de transición hacia nuevas formas de producir, de consumir, pero también hacia nuevas formas de ser.  Es un proceso multidimensional y complejo, que debe caracterizarse por su innovación, creatividad y apertura. Sin embargo, la dependencia de la política nacional e internacional de la economía micro y macro, de la cultura regional y global, hacen que el concepto se torne difícil de visualizar como un proceso autóctono y que obedezca a las necesidades reales de las personas y comunidades de un país.

  13. Desafíos demográficos para un desarrollo sustentable. Declaración de Laxenburg sobre Población y Desarrollo Sustentable

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Convencido de la necesidad de integrar los tres pilares del desarrollo sustentable -desarrollo económico, desarrollo social y protección del medio ambiente-, el Instituto Internacional de Análisis de Sistemas Aplicados (iiasa reunió a más de veinte expertos en población y desarrollo para discutir sobre cómo los factores poblacionales promueven o impiden un desarrollo sustentable. La reunión contó con el apoyo del Fondo de Población de Naciones Unidas y se llevó a cabo en las instalaciones de iiasa, en Viena, del 30 de septiembre al 1 de octubre de 2011. El panel de expertos propuso cinco acciones amplias que recomienda en el marco de la Conferencia Río+20 de Naciones Unidas sobre Desarrollo Sustentable. A continuación se incluyen sus conclusiones y recomendaciones.

  14. Desarrollo de un drive para motores paso a paso y aplicación del filtro de Kalman para el sistema de colimación del LHC = Development of a stepper motor drive and Kalman Filter application for the LHC collimation system

    OpenAIRE

    Picatoste Ruilope, Ricardo

    2010-01-01

    Este proyecto describe el trabajo realizado durante 14 meses en una estancia en prácticas para estudiantes del CERN. El trabajo consiste en el desarrollo, implementación y testeo de un drive para motores paso a paso que se utilizará en el sistema de colimación del LHC. Se propone así mismo la utilización del filtro de Kalman para obtener una estimación del ángulo, desarrollandose una implementación del mismo aplicable en tiempo real.

  15. Evaluation of the influence of the TH-GEM detector components in dosimetric measurements of standard mammography beams

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natália F.; Castro, Maysa C.; Caldas, Linda V.E., E-mail: nsilva@ipen.br, E-mail: maysadecastro@gmail.com, E-mail: fbelonsi@gmail.com, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Silva, Tiago F.; Cintra, Felipe B.; Luz, Hugo N. da, E-mail: tfsilva@if.usp.br, E-mail: hugonluz@if.usp.br [Universidade de São Paulo (IF/USP), São Paulo, SP (Brazil). Instituto de Física

    2017-07-01

    GEM detectors have found applications in many areas due to their simplicity of construction, low cost, ruggedness and diversity of shape. A dosimeter with these qualities presents utility in several applications, as for example in diagnostic and therapeutic medicine, industrial radiography and nuclear meters. Furthermore, the high sensitivity provided by GEM detectors may extend their applications in low dose dosimetry. Based on these facts, it may be interesting to produce a prototype of a portable TH-GEM type detector with characteristics suitable for dosimetric use in X-rays with low and medium energies. The precise determination of the dosimeter characteristics is very important for laboratories of instrument calibration, as well as to determine how the various components of the detector may influence on the energy deposited in the sensitive volume. In this work, the results obtained about the influence of each one of the components present in this type of detector in standard mammography beams is presented. The code MCNP5 was used. The results allowed the adaptation of the detector to the desired conditions. (author)

  16. RURAL DEVELOPMENT: MORE THAN SINGLE AGRICULTURAL DEVELOPMENT DESARROLLO RURAL: MÁS QUE DESARROLLO AGRÍCOLA

    Directory of Open Access Journals (Sweden)

    Pachón Ariza Fabio Alberto

    2007-11-01

    Full Text Available Rural development as the notion of development has been strongly influenced by the idea of economic growth. Conversely, the rural development road has been focus on agricultural modernization of production systems, intensive use of chemical inputs to increase levels and technology transfer. The actual rural reality has conducted to a revaluation of what rural means and therefore its development. In these sense has grown the importance of rural related activities linked to the diversification and generating of extra revenues for rural families. This could be one of the cases behind this change in perceptions on previous rural development, giving more importance to other aspects such as cultural diversity, community participation, decision taking, decentralization processes, cultural values, and in consequence hot associate rural development with agricultural development.El desarrollo rural al igual que el sólo desarrollo, ha estado fuertemente influenciado por la idea que lo liga con el crecimiento económico. Concebido de esta forma, la manera como se ha intentado alcanzar desarrollo rural ha sido por medio de la modernización de los sistemas de producción agropecuaria, del uso indiscriminado de insumos químicos para aumentar los niveles productivos y de transferencia de tecnología. La realidad que se vive en el sector rural ha hecho que se evolucione hacia una revaloración de lo que significa lo rural y, de esta manera, también su desarrollo. Por este camino han tomado más importancia actividades conexas a lo productivo agropecuario y también la diversificación de las formas de generación de ingresos para las familias rurales. Ésta podría ser una de las causas para que también cambie la percepción que existía sobre el desarrollo rural y se brinde más importancia a otros aspectos como la aceptación de la diversidad, la participación de la comunidad en la toma de decisiones, la descentralización de la administración, el

  17. Development and design of an antropomorphic model for electron dosimetric purposes

    International Nuclear Information System (INIS)

    Geske, G.; Geske, J.

    1977-01-01

    After discussing some problems related to the planning of therapeutic irradiation with fast electron the benifit of phantoms for electron dosimetric purposes is pointed out. The selection of tissue-equivalent materials for constructing a phantom is dicussed in detail. Finally, a model representing the upper part of a female body is described. (author)

  18. The features of radiation induced lung fibrosis related with dosimetric parameters

    International Nuclear Information System (INIS)

    Oh, Young-Taek; Noh, O Kyu; Jang, Hyunsoo; Chun, Mison; Park, Kyung Joo; Park, Kwang Joo; Kim, Mi-Hwa; Park, Hae-Jin

    2012-01-01

    Background and purpose: Radiation induced lung fibrosis (RILF) is a major complication after lung irradiation and is very important for long term quality of life and could result in fatal respiratory insufficiency. However, there has been little information on dosimetric parameters for radiotherapy planning in the aspect of RILF. The features of RILF related with dosimetric parameters were evaluated. Methods and materials: Forty-eight patients with non-small cell lung carcinoma who underwent post-operative radiation therapy (PORT) without adjuvant chemotherapy were analyzed. The degree of lung fibrosis was estimated by fibrosis volume and the dosimetric parameters were calculated from the plan of 3-dimensional conformal radiotherapy. Results: The fibrosis volume and V-dose as dosimetric parameters showed significant correlation and the correlation coefficient ranged from 0.602 to 0.683 (P < 0.01). The degree of the correlation line was steeper as the dose increase and threshold dose was not found. Mean lung dose (MLD) showed strong correlation with fibrosis volume (correlation coefficient = 0.726, P < 0.01). Conclusions: The fibrosis volume is continuously increased with V-dose as the reference dose increases. MLD is useful as a single parameter for comparing rival plans in the aspect of RILF.

  19. Dosimetric study to voxel model applied to cardiac exams in Nuclear medicine

    International Nuclear Information System (INIS)

    Cassola, V.F.; Silva, A.M. Marques da; Hoff, G.

    2008-01-01

    The objective of this study is to analyze the dosimetry in a simplified model of the region of interest of myocardial perfusion studies considering different descriptions of Tc-99m emission spectra. It aims to assess the implications of these different approaches in the description of Tc-99m spectrum, as well as their dosimetric implications

  20. Tenon hospital 3-D dosimetric methodology for radiosurgery of complex AVMs

    International Nuclear Information System (INIS)

    Lefkopoulos, D.; Schlienger, M.; Plazas, M.C.; Laugier, A.

    1990-01-01

    This paper presents the methodology of the irradiation treatment planning for the calculation of the 3-D dose distribution developed at the Tenon Hospital since four years. This dosimetric method is independent of the Linac irradiation technique, thus is can be used with any other type of radiosurgery technique. (author)

  1. Geometric factors influencing dosimetric sparing of the parotid glands using IMRT

    International Nuclear Information System (INIS)

    Hunt, Margie A.; Jackson, Andrew; Narayana, Ashwatha; Lee, Nancy

    2006-01-01

    Purpose/Objective: To determine the relationship between the parotid volume, parotid-planning target volume (PTV) overlap, and dosimetric sparing of the parotid with intensity-modulated radiation therapy (IMRT). Methods and Materials: Parotid data were collected retrospectively for 51 patients treated with simultaneous boost IMRT. Unresectable patients received 54 or 59.4 Gy to subclinical disease, 70 Gy to gross disease. Patients treated postoperatively received 54, 60, and 66 Gy to low-risk, high-risk, and tumor bed regions. Volume and mean dose of each gland and gland segments outside of and overlapping the PTV were collected. Proximity of each gland to each PTV was recorded. Results: Dosimetric sparing (mean dose ≤26.5 Gy) was achieved in 66 of 71 glands with ≤21% parotid-PTV overlap and 8 of 23 glands with >21% overlap (p = 21%. Median mean dose was 25.9 Gy to glands overlapping PTV 54 or PTV 59 alone and 30.0 Gy to those abutting PTV 7 (p 7 was associated with higher parotid dose, satisfactory sparing was achieved in 24 of 43 ipsilateral glands. Conclusions: Dosimetric sparing of the parotid is feasible when the parotid-PTV overlap is less than approximately 20%. With more overlap, sparing may result in low doses within the overlap region, possibly leading to inadequate PTV coverage. Gland proximity to the high-dose PTV is associated with higher mean dose but does not always preclude dosimetric sparing

  2. Validation of the implementation of IMRT with three dosimetric methods of independent verification

    International Nuclear Information System (INIS)

    Tortosa Oliver, R. A.; Chinillach ferrando, N.; Alonso Arrizabalaga, S.; Campayo Esteban, J. M.; Morales Marco, J. C.; Soler Catalan, P.; Andreu Martinez, F. J.

    2013-01-01

    The TG119 is a simple and clear framework to verify the implementation of IMRT technique in a radiotherapy service. Verifications of this document recommended tests conducted with the three dosimetric methods listed above, allow to affirm that our Center is within the margins of tolerance considered suitable in the TG119 for the clinical implementation of IMRT. (Author)

  3. Dosimetric response evaluation of tooth enamel for accelerator-based neutron radiation

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

    2003-01-01

    To study the neutron response of human tooth enamel, a number of experiments with an accelerator-based neutron source have been designed. The neutron beam was produced with the low gamma yield, 7 Li(p,n) 7 Be type thick target, using the 3 MV McMaster K.N. Van de Graaff accelerator. The dosimetry was done using a pre-calibrated snoopy type neutron dosimeter. Neutron irradiation induces a dosimetric signal in the tooth enamel at the same defect site as gamma produced damage with the same g-values (g parallel =1.9973, width 0.4 mT g perpendicular =2.002, width 0.3 mT). The dosimetric signal grows linearly with neutron dose from 6-35 Gy tissue dose. Dosimetric response in two different grain sizes (300-500 μm, and grains <4 mm) has shown increased dosimetric amplitude in the larger grains. Dose build up effect on tooth inside the mouth due to cheek was simulated by placing a 4 mm thick paraffin wax layer between the beam and tooth, but had little effect. These results show that for mean neutron energy of 280 keV, the relative neutron response of the human tooth enamel ranges from 8% to 12% of the equivalent gamma ray response

  4. Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy-absorption...

  5. Internal dosimetric evaluation due to uranium aerosols; Evaluacion dosimetrica interna debido a aerosoles de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Juan, Garcia Aguilar; Gustavo, Delgado Avila [Instituto Nacional de Investigaciones Nucleares, Salazar (Mexico)

    1991-07-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research.

  6. La cooperación al desarrollo humano: visión y alcance del enfoque de desarrollo humano en la cooperación internacional del PNUD

    OpenAIRE

    De Angelis, Ignacio

    2010-01-01

    El objetivo del presente trabajo consiste en analizar el alcance del enfoque del desarrollo humano en los objetivos propuestos por los programas de las instituciones de cooperación internacional al desarrollo. La cooperación para el desarrollo es un concepto en constante movimiento, ya que a lo largo del tiempo su contenido se transforma adaptándose e incorporando en la actualidad lineamientos relativos al enfoque de desarrollo humano. Para explorar el alcance de este enfoque se adopta como r...

  7. Basic Principles and Practices of Integrated Dosimetric Passportization of the Settlements in Ukraine.

    Science.gov (United States)

    Likhtarov, I A; Kovgan, L M; Masiuk, S V; Ivanova, O M; Chepurny, M I; Boyko, Z N; Gerasymenko, V B

    2015-12-01

    The purpose of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of aftermath of the Chornobyl accident directed on recovery through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring.The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014.The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 raions in 12 oblasts during all the post-accident period. Thanks to the works of dosimetric passportization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number

  8. Basic principles and practices of integrated dosimetric passportization of the settlements in Ukraine

    International Nuclear Information System (INIS)

    Lyikhtar'ov, Yi.A.; Kovgan, L.M.; Masyuk, S.V.; Yivanova, O.M.; Chepurnij, M.Yi.; Bojko, Z. N.; Gerasimenko, V.B.

    2015-01-01

    The objective of the review is to demonstrate the results of dosimetric passportization (performed in 1991- 2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of after- math of the Chornobyl accident through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring. The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014. The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 districts in 12 regions during all the post-accident period. Thanks to the works of dosimetric passportization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important

  9. Non-dosimetric quality assurance for the three-dimensional radiation treatment planning systems using a multi-leaf collimator phantom

    International Nuclear Information System (INIS)

    Tateoka, Kunihiko; Nagase, Daiki; Sato, Takahito; Shimizume, Kazunari; Ouchi, Atsushi; Nakata, Kensei; Hareyama, Masato

    2008-01-01

    Evaluation of errors and limitations in simulation software for three-dimensional radiation treatment systems (3D-RTPS) is an important issue. Non-dosimetric quality assurance (QA) of the simulation software of 3D-RTPS was evaluated by graphical displays of JAW and multi-leaf collimator (MLC) settings in a 3D-RTPS. The influence of observations made using the phantom depends on human errors and several parameters of the CT scan set, such as slice thickness and spacing, pixel size, partial volume effects and the reconstructed image orientation. We explored the methods that were minimally influenced by these errors and parameters. The QA phantom (MLC phantom) has been designed for checking a JAW and MLC settings in a 3D-RTPS is used for non-dosimetric QA. We analyzed the CT value of the boundary the structures of the MLC phantom. The relative CT value for thickness 1 mm slice in border of each structure body of MLC phantom respectively shows a decrease of about 2%, 4%, 10% by 2 mm, 3 mm and 5 mm. In case of thickness 5 mm slice, the mean deference of border of virtual radiation beams and phantom was 0.8 mm, and standard deviation of them was 0.6 mm. And the mean difference of border of a DRR image and phantom was 0.08 mm and the standard deviation of them 0.6 mm. In case of thickness 2 mm slice, the mean deference of border of virtual radiation beams and phantom was -0.18 mm, and standard deviation of them was 0.32 mm. And the mean difference of border of a DRR image and phantom was 0.87 mm and the standard deviation of them 0.54 mm. The result of the study is useful for improvement in a precision of non-dosimetric QA. Our method of non-dosimetric QA can minimize human error and influence of several parameters of the CT scan set. The MLC phantom is a useful tool in the QA of radiation therapy with application to 3D-RTPS, CT simulators, and virtual simulation packages with MLC display capabilities. (author)

  10. SU-D-204-01: A Methodology Based On Machine Learning and Quantum Clustering to Predict Lung SBRT Dosimetric Endpoints From Patient Specific Anatomic Features

    Energy Technology Data Exchange (ETDEWEB)

    Lafata, K; Ren, L; Wu, Q; Kelsey, C; Hong, J; Cai, J; Yin, F [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: To develop a data-mining methodology based on quantum clustering and machine learning to predict expected dosimetric endpoints for lung SBRT applications based on patient-specific anatomic features. Methods: Ninety-three patients who received lung SBRT at our clinic from 2011–2013 were retrospectively identified. Planning information was acquired for each patient, from which various features were extracted using in-house semi-automatic software. Anatomic features included tumor-to-OAR distances, tumor location, total-lung-volume, GTV and ITV. Dosimetric endpoints were adopted from RTOG-0195 recommendations, and consisted of various OAR-specific partial-volume doses and maximum point-doses. First, PCA analysis and unsupervised quantum-clustering was used to explore the feature-space to identify potentially strong classifiers. Secondly, a multi-class logistic regression algorithm was developed and trained to predict dose-volume endpoints based on patient-specific anatomic features. Classes were defined by discretizing the dose-volume data, and the feature-space was zero-mean normalized. Fitting parameters were determined by minimizing a regularized cost function, and optimization was performed via gradient descent. As a pilot study, the model was tested on two esophageal dosimetric planning endpoints (maximum point-dose, dose-to-5cc), and its generalizability was evaluated with leave-one-out cross-validation. Results: Quantum-Clustering demonstrated a strong separation of feature-space at 15Gy across the first-and-second Principle Components of the data when the dosimetric endpoints were retrospectively identified. Maximum point dose prediction to the esophagus demonstrated a cross-validation accuracy of 87%, and the maximum dose to 5cc demonstrated a respective value of 79%. The largest optimized weighting factor was placed on GTV-to-esophagus distance (a factor of 10 greater than the second largest weighting factor), indicating an intuitively strong

  11. Normas farmacológicas cubanas: desarrollo e impacto

    Directory of Open Access Journals (Sweden)

    Celeste Aurora Sánchez González

    2003-08-01

    Full Text Available Se describió la importancia como instrumento de consulta, del compendio nacional de sustancias activas y asociaciones de uso farmacéutico industrial aceptadas y rechazadas en Cuba. Se identificó la información de seguridad para el uso racional que incorpora la clasificación terapéutica adoptada y la estructura organizativa de estas Normas Farmacológicas Cubanas (NFC. Se cuantificó su aplicación por el Centro para el Control de la Calidad de los Medicamentos (CECMED, usuarios cubanos y extranjeros durante el período 1996 al 2000, para determinar grados de novedad y caracterización terapéutica, mediante el análisis de Ensayos Clínicos Autorizados y Registros de Medicamentos otorgados. Se dimensionó el impacto en la Reglamentación Farmacéutica Nacional y la interacción con otras regulaciones. Se identificaron las perspectivas de desarrollo en su alcance y contenido. Se concluyó la utilidad de las NFC en la adecuada clasificación del grado de novedad de los productos, el ágil y preciso manejo y evaluación de trámites, así como en la caracterización del enfoque terapéutico.The importance as a consultation tool of the National Compendium of active ingredients for industrial pharmaceutical use and its combinations that are accepted and refused in Cuba was described. The safety information for their rational use that includes the adopted therapeutic classification and the organizational structuring of the Cuban Pharmacological Standards were identified. Its application was quantified by the Center for Drug Quality Control (CECMED , by national and foreign users in the period 1996-2000, in order to identify the degree of novelty of products and the therapeutical characterization by analysing the authorised clinical trials and the register of provided drugs. The impact on the National Pharmaceutical Regulation, and the interrelation with other regulations were shown. The scope and contents of the development prospects were stated

  12. Genómica Funcional de Plantas: Estudio del Desarrollo de Flores y Frutos Genómica Funcional de Plantas: Estudio del Desarrollo de Flores y Frutos

    Directory of Open Access Journals (Sweden)

    Octavio Rubén Salazar Moya

    2012-02-01

    Full Text Available La última fase del desarrollo floral es la fertilización de los óvulos y la formación de los frutos,que son muy importantes tanto biológica como económicamente. Notoriamente, más del 80% de los alimentos que son consumidos por el ser humano proviene de flores y frutos.La obtención de conocimientos acerca de las bases moleculares del desarrollo de frutos en especies modelo es de gran interés científico, y un paso indispensable para poder facilitar investigaciones y de ser factible, aplicaciones en frutos de consumo humano. Especialmente en un país como México, con tal riqueza en la diversidad de frutos, este tipo de estudios es necesario y científicamente muy interesante, y tiene repercusiones económicas potenciales importantes. La meta del laboratorio es descubrir genes nuevos involucrados en el desarrollo de frutos, empleando los recursos que brindan plantas modelo como Arabidopsisthaliana. Se hace un enfoque especial en genes que afectan la identidad celular, morfología y que causan partenocarpia (frutos carentes de semillas, para más tarde estudiarlos enotras especies y hacer ensayos para conocer sus alcances en dichas especies.The last stages of fl oral development are ovule fertilization and fruit formation. Fruits are very important both biologically and economically. Notably, more than 80% of human food is obtained from flowers and fruits. Gathering basic knowledge about the molecular mechanisms of fruit development from model species is of great scientific interest, and is an essential step to facilitate research and, when feasible, applications in fruits consumed by humans. Especially in countries like Mexico, which has such a great diversity of fruits, this kind of research is both necessary and scientifically interesting, and has potentially important economic repercussions. The goal of the lab is to discover new genes that are involved inflower development, making use of the resources provided by model plants like

  13. Patient feature based dosimetric Pareto front prediction in esophageal cancer radiotherapy.

    Science.gov (United States)

    Wang, Jiazhou; Jin, Xiance; Zhao, Kuaike; Peng, Jiayuan; Xie, Jiang; Chen, Junchao; Zhang, Zhen; Studenski, Matthew; Hu, Weigang

    2015-02-01

    To investigate the feasibility of the dosimetric Pareto front (PF) prediction based on patient's anatomic and dosimetric parameters for esophageal cancer patients. Eighty esophagus patients in the authors' institution were enrolled in this study. A total of 2928 intensity-modulated radiotherapy plans were obtained and used to generate PF for each patient. On average, each patient had 36.6 plans. The anatomic and dosimetric features were extracted from these plans. The mean lung dose (MLD), mean heart dose (MHD), spinal cord max dose, and PTV homogeneity index were recorded for each plan. Principal component analysis was used to extract overlap volume histogram (OVH) features between PTV and other organs at risk. The full dataset was separated into two parts; a training dataset and a validation dataset. The prediction outcomes were the MHD and MLD. The spearman's rank correlation coefficient was used to evaluate the correlation between the anatomical features and dosimetric features. The stepwise multiple regression method was used to fit the PF. The cross validation method was used to evaluate the model. With 1000 repetitions, the mean prediction error of the MHD was 469 cGy. The most correlated factor was the first principal components of the OVH between heart and PTV and the overlap between heart and PTV in Z-axis. The mean prediction error of the MLD was 284 cGy. The most correlated factors were the first principal components of the OVH between heart and PTV and the overlap between lung and PTV in Z-axis. It is feasible to use patients' anatomic and dosimetric features to generate a predicted Pareto front. Additional samples and further studies are required improve the prediction model.

  14. Dosimetric evaluation of whole-breast radiation therapy: Clinical experience

    International Nuclear Information System (INIS)

    Osei, Ernest; Darko, Johnson; Fleck, Andre; White, Jana; Kiciak, Alexander; Redekop, Rachel; Gopaul, Darin

    2015-01-01

    Radiation therapy of the intact breast is the standard the