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Wendling, M.
Westinghouse Hanford Co., Richland, WA (United States). Funding organisation: USDOE, Washington, DC (United States)1994
Westinghouse Hanford Co., Richland, WA (United States). Funding organisation: USDOE, Washington, DC (United States)1994
AbstractAbstract
[en] This report summarizes and documents the results of the radiological surveys conducted from February 11 through February 17 and March 30, 1993 over the 618-10 Burial Ground, Hanford Site, Richland, Washington. In addition, this report explains the survey methodology using the Ultrasonic Ranging and Data System (USRADS). The 618-10 Burial Ground radiological survey field task consisted of two activities: characterization of the specific background conditions and the radiological survey of the area. The radiological survey of the 618-10 Burial Ground, along with the background study, were conducted by Site Investigative Surveys Environmental Restoration Health Physics Organization of the Westinghouse Hanford Company. The survey methodology was based on utilization of the Ultrasonic Ranging and Data System (USRADS) for automated recording of the gross gamma radiation levels at or near six (6) inches and at three (3) feet from the surface soil
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26 May 1994; 14 p; CONTRACT AC06-87RL10930; Also available from OSTI as DE94014125; NTIS; US Govt. Printing Office Dep
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Report
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AbstractAbstract
No abstract available
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Dwyer, O.E. (ed.); p. 81-92; 1973; Pergamon Press, Inc; Elmsford, NY; 4. international seminar on heat and mass transfer in liquid metals; Trojir, Yugoslavia; 6 Sep 1971
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Book
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Wendling, M.; Ricque, R.; Martin, R.
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France). Dept. de Transfert et Conversion d'Energie1972
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France). Dept. de Transfert et Conversion d'Energie1972
AbstractAbstract
No abstract available
Original Title
Etude experimentale de la convection mixte en sodium
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Source
1972; 6 p; French hydrotechnical society. 12. Meeting on hydraulics; Paris, France; 06 Jun 1972; 18 refs.; 5 figs.
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Report
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Wendling, M.; Ricque, R.; Martin, R.
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)1971
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)1971
AbstractAbstract
No abstract available
Original Title
Convection mixte dans le sodium
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1971; 22 p; 4. International seminar on heat and mass transfer in liquid metals; Trogir, Yugoslavia; 06 Sep 1971
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Report
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Conference
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Wendling, M.; Martin, R.; Ricque, R.
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France). Service des Transferts Thermiques1971
CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France). Service des Transferts Thermiques1971
AbstractAbstract
No abstract available
Original Title
Etude experimentale de la convection mixte en canal
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Source
1971; 8 p; 14. Congress of the International Association for Hydraulic Research; Paris, France; 27 Aug 1971
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Report
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AbstractAbstract
No abstract available
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Dwyer, O.E. (ed.) (Brookhaven National Lab., Upton, N.Y. (USA)); Progress in Heat and Mass Transfer; v. 7; p. 81-92; ISBN 0080171265; ; 1973; Pergamon; Oxford, UK; International seminar on liquid-metal heat transfer; Trogir, Yugoslavia; 6 Sep 1971
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Book
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Wendling, M.; Martin, R.; Ricque, R.
14. Congress of the International Association for Hydraulic Research1971
14. Congress of the International Association for Hydraulic Research1971
AbstractAbstract
No abstract available
Original Title
Etude experimentale de la convection mixte en canal
Primary Subject
Source
Societe Hydrotechnique de France, 75 - Paris; p. 309-316; 1971; Societe Hydrotechnique de France; Paris, France; 14. Congress of the International Association for Hydraulic Research; Paris, France; 29 Aug 1971
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Book
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AbstractAbstract
[en] Irradiation of the heart is one of the major concerns during radiotherapy of breast cancer. Three-dimensional (3D) treatment planning would therefore be useful but cannot always be performed for left-sided breast treatments, because CT data may not be available. However, even if 3D dose calculations are available and an estimate of the normal tissue damage can be made, uncertainties in patient positioning may significantly influence the heart dose during treatment. Therefore, 3D reconstruction of the actual heart dose during breast cancer treatment using electronic imaging portal device (EPID) dosimetry has been investigated. A previously described method to reconstruct the dose in the patient from treatment portal images at the radiological midsurface was used in combination with a simple geometrical model of the irradiated heart volume to enable calculation of dose-volume histograms (DVHs), to independently verify this aspect of the treatment without using 3D data from a planning CT scan. To investigate the accuracy of our method, the DVHs obtained with full 3D treatment planning system (TPS) calculations and those obtained after resampling the TPS dose in the radiological midsurface were compared for fifteen breast cancer patients for whom CT data were available. In addition, EPID dosimetry as well as 3D dose calculations using our TPS, film dosimetry, and ionization chamber measurements were performed in an anthropomorphic phantom. It was found that the dose reconstructed using EPID dosimetry and the dose calculated with the TPS agreed within 1.5% in the lung/heart region. The dose-volume histograms obtained with EPID dosimetry were used to estimate the normal tissue complication probability (NTCP) for late excess cardiac mortality. Although the accuracy of these NTCP calculations might be limited due to the uncertainty in the NTCP model, in combination with our portal dosimetry approach it allows incorporation of the actual heart dose. For the anthropomorphic phantom, and for fifteen patients for whom CT data were available to test our method, the average difference between the NTCP values obtained with our method and those resulting from the dose distributions calculated with the TPS was 0.1% ±0.3% (1 SD). Most NTCP values were 1%-2% lower than those obtained using the method described by Hurkmans et al. [Radiother. Oncol. 62, 163-171 (2002)], using the maximum heart distance determined from a simulator image as a single pre-treatment parameter. A similar difference between the two methods was found for twelve patients using in vivo EPID dosimetry; the average NTCP value obtained with EPID dosimetry was 0.9%, whereas an average NTCP value of 2.2% was derived using the method of Hurkmans et al. The results obtained in this study show that EPID dosimetry is well suited for in vivo verification of the heart dose during breast cancer treatment, and can be used to estimate the NTCP for late excess cardiac mortality. To the best of our knowledge, this is the first study using portal dosimetry to calculate a DVH and NTCP of an organ at risk
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(c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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AbstractAbstract
[en] This study was carried out to determine the stability of the response of amorphous silicon (a-Si)-flat panel imagers for dosimetry applications. Measurements of the imager's response under reference conditions were performed on a regular basis for four detectors of the same manufacturer. We found that the ambient temperature influenced the dark-field, while the gain of the imager signal was unaffected. Therefore, temperature fluctuations were corrected for by applying a 'dynamic' dark-field correction. This correction method also removed the influence of a small, irreversible increase of the dark-field current, which was equal to 0.5% of the dynamic range of the imager per year and was probably caused by mild radiation damage to the a-Si array. By applying a dynamic dark-field correction, excellent stability of the response over the entire panel of all imagers of 0.5% (1 SD) was obtained over an observation period up to 23 months. However, two imagers had to be replaced after several months. For one imager, an image segment stopped functioning, while the image quality of the other imager degraded significantly. We conclude that the tested a-Si EPIDs have a very stable response and are therefore well suited for dosimetry. We recommend, however, applying quality assurance tests dedicated to both imaging and dosimetry
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(c) 2004 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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AbstractAbstract
[en] The aim of this study was to demonstrate how dosimetry with an amorphous silicon electronic portal imaging device (a-Si EPID) replaced film and ionization chamber measurements for routine pre-treatment dosimetry in our clinic. Furthermore, we described how EPID dosimetry was used to solve a clinical problem. IMRT prostate plans were delivered to a homogeneous slab phantom. EPID transit images were acquired for each segment. A previously developed in-house back-projection algorithm was used to reconstruct the dose distribution in the phantom mid-plane (intersecting the isocenter). Segment dose images were summed to obtain an EPID mid-plane dose image for each field. Fields were compared using profiles and in two dimensions with the γ evaluation (criteria: 3%/3 mm). To quantify results, the average γ (γavg), maximum γ (γmax), and the percentage of points with γ<1(Pγlt1) were calculated within the 20% isodose line of each field. For 10 patient plans, all fields were measured with EPID and film at gantry set to 0 deg. . The film was located in the phantom coronal mid-plane (10 cm depth), and compared with the back-projected EPID mid-plane absolute dose. EPID and film measurements agreed well for all 50 fields, with <γavg>=0.16, <γmax>=1.00, and < Pγlt1>=100%. Based on these results, film measurements were discontinued for verification of prostate IMRT plans. For 20 patient plans, the dose distribution was re-calculated with the phantom CT scan and delivered to the phantom with the original gantry angles. The planned isocenter dose (planiso) was verified with the EPID (EPIDiso) and an ionization chamber (ICiso). The average ratio, < EPIDiso/ICiso>, was 1.00 (0.01 SD). Both measurements were systematically lower than planned, with < EPIDiso/planiso> and < ICiso/planiso>=0.99 (0.01 SD). EPID mid-plane dose images for each field were also compared with the corresponding plane derived from the three dimensional (3D) dose grid calculated with the phantom CT scan. Comparisons of 100 fields yielded <γavg>=0.39, γmax=2.52, and < Pγlt1>=98.7%. Seven plans revealed under-dosage in individual fields ranging from 5% to 16%, occurring at small regions of overlapping segments or along the junction of abutting segments (tongue-and-groove side). Test fields were designed to simulate errors and gave similar results. The agreement was improved after adjusting an incorrectly set tongue-and-groove width parameter in the treatment planning system (TPS), reducing <γmax> from 2.19 to 0.80 for the test field. Mid-plane dose distributions determined with the EPID were consistent with film measurements in a slab phantom for all IMRT fields. Isocenter doses of the total plan measured with an EPID and an ionization chamber also agreed. The EPID can therefore replace these dosimetry devices for field-by-field and isocenter IMRT pre-treatment verification. Systematic errors were detected using EPID dosimetry, resulting in the adjustment of a TPS parameter and alteration of two clinical patient plans. One set of EPID measurements (i.e., one open and transit image acquired for each segment of the plan) is sufficient to check each IMRT plan field-by-field and at the isocenter, making it a useful, efficient, and accurate dosimetric tool
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(c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
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