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[PMID]:28749375
[Au] Autor:Kontaxis C; Bol GH; Stemkens B; Glitzner M; Prins FM; Kerkmeijer LGW; Lagendijk JJW; Raaymakers BW
[Ad] Endereço:Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, Utrecht 3584 CX, The Netherlands.
[Ti] Título:Towards fast online intrafraction replanning for free-breathing stereotactic body radiation therapy with the MR-linac.
[So] Source:Phys Med Biol;62(18):7233-7248, 2017 Aug 21.
[Is] ISSN:1361-6560
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The hybrid MRI-radiotherapy machines, like the MR-linac (Elekta AB, Stockholm, Sweden) installed at the UMC Utrecht (Utrecht, The Netherlands), will be able to provide real-time patient imaging during treatment. In order to take advantage of the system's capabilities and enable online adaptive treatments, a new generation of software should be developed, ranging from motion estimation to treatment plan adaptation. In this work we present a proof of principle adaptive pipeline designed for high precision stereotactic body radiation therapy (SBRT) suitable for sites affected by respiratory motion, like renal cell carcinoma (RCC). We utilized our research MRL treatment planning system (MRLTP) to simulate a single fraction 25 Gy free-breathing SBRT treatment for RCC by performing inter-beam replanning for two patients and one volunteer. The simulated pipeline included a combination of (pre-beam) 4D-MRI and (online) 2D cine-MR acquisitions. The 4DMRI was used to generate the mid-position reference volume, while the cine-MRI, via an in-house motion model, provided three-dimensional (3D) deformable vector fields (DVFs) describing the anatomical changes during treatment. During the treatment fraction, at an inter-beam interval, the mid-position volume of the patient was updated and the delivered dose was accurately reconstructed on the underlying motion calculated by the model. Fast online replanning, targeting the latest anatomy and incorporating the previously delivered dose was then simulated with MRLTP. The adaptive treatment was compared to a conventional mid-position SBRT plan with a 3 mm planning target volume margin reconstructed on the same motion trace. We demonstrate that our system produced tighter dose distributions and thus spared the healthy tissue, while delivering more dose to the target. The pipeline was able to account for baseline variations/drifts that occurred during treatment ensuring target coverage at the end of the treatment fraction.
[Mh] Termos MeSH primário: Fracionamento de Dose
Imagem por Ressonância Magnética
Aceleradores de Partículas
Radiocirurgia/instrumentação
Planejamento da Radioterapia Assistida por Computador/métodos
Radioterapia Guiada por Imagem/instrumentação
[Mh] Termos MeSH secundário: Seres Humanos
Movimento
Respiração
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1088/1361-6560/aa82ae


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[PMID]:29290555
[Au] Autor:Ben Salem L; Essadok A; Saidani I; Mahdouani M; Benna M; Mahjoubi K; Besbes M; Benna F
[Ad] Endereço:Unité de radiophysique, service de radiothérapie, institut Salah-Azaiz de Tunis, boulevard 9-Avril, 1006 Tunis, Tunisie. Electronic address: lotfi.bsalem@gmail.com.
[Ti] Título:[Experimental determination of correction factors of four detectors used in small field radiotherapy].
[Ti] Título:Détermination expérimentale des facteurs de correction de quatre détecteurs actifs utilisés pour la dosimétrie des minifaisceaux utilisés en radiothérapie..
[So] Source:Cancer Radiother;22(1):45-51, 2018 Feb.
[Is] ISSN:1769-6658
[Cp] País de publicação:France
[La] Idioma:fre
[Ab] Resumo:PURPOSE: The aim of this work is to determine experimentally the correction factors [Formula: see text] for four active commercial dosimeters: two microchambers and two diode detectors based on the output factor measured with radiochromic film for a radiotherapy linear accelerator equipped with circular cones. MATERIALS AND METHODS: Initially, a radiochromic film dosimetry measurement protocol with an accuracy of 2% was developed to approach the "reference output factor". Afterwards, the corrective factors of four detectors were determined for two ionization chambers (PinPoint PTW 31016 3D, Micropoint Extradin A16) and two diodes (PTW T60017 Diode, PTW-60019 Micro-Diamond). These measurements were carried out under conical BrainLAB collimators defining circular fields with diameters equal to 7.5mm, 10mm, 12.5mm, 15mm, 17.5mm, 20mm, 25mm, 30mm, 35mm and 45mm of a 6MV X-ray beam generated by the ClinaciX linear accelerator (Varian ). These factors are weakly dependent on the type of accelerator, whether the model and the collimation type. This allowed their comparisons with those published for the same type of detector and for an accelerator with the same index of beam quality. RESULTS: The correction factors obtained experimentally were comparable in maximum deviation of 1.9% with published ones of the works using the same type of detector (mark and model) and an accelerator delivering the same beam quality for the same field size at the measurement point. CONCLUSION: The measurement protocol using the EBT3 film, which was used as a passive dosimeter to determine the "reference output factor", was validated by comparing measured and published data of active detector correction factors.
[Mh] Termos MeSH primário: Radiometria/instrumentação
[Mh] Termos MeSH secundário: Seres Humanos
Método de Monte Carlo
Aceleradores de Partículas
Radiocirurgia
Planejamento da Radioterapia Assistida por Computador
Software
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180220
[Lr] Data última revisão:
180220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180102
[St] Status:MEDLINE


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[PMID]:28749813
[Au] Autor:Waller E; Ram R; Steadman I
[Ad] Endereço:*University of Ontario Institute of Technology, Faculty of Energy Systems and Nuclear Science Oshawa, Ontario Canada.
[Ti] Título:Preliminary Determination of Activation Products for a Varian Truebeam Linear Accelerator.
[So] Source:Health Phys;113(3):227-233, 2017 09.
[Is] ISSN:1538-5159
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Medical linear accelerators used to treat various forms of cancers are operated at a number of different energies. A by-product of the high-energy photons produced by accelerators is activation of components within the machine itself and its surrounding bunker. The activation products pose radiological and regulatory challenges during the operation of the accelerator as well as when it is time for final decommissioning. The Varian TrueBeam is a new state-of-the-art linear accelerator now operating in the Canadian market. There is currently limited information on the production of its activation products and the resulting impacts on operation and decommissioning. In this paper, activation products in the Varian TrueBeam accelerator are experimentally determined by performing gamma spectroscopy using a portable high purity germanium detector. A total of 10 isotopes are identified for the conditions tested, which include Na, Al, Mn, Ni, Cu, Cu, Br, Sb, Sb, W. The half-lives of these isotopes range from 2.3 min to 60.2 d. These preliminary results indicate that a decommissioning case similar to other radiotherapy accelerators can be made.
[Mh] Termos MeSH primário: Aceleradores de Partículas
[Mh] Termos MeSH secundário: Seres Humanos
Exposição Ocupacional
Dose de Radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1097/HP.0000000000000693


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[PMID]:28749809
[Au] Autor:Piper RK; Mozhayev AV; Murphy MK; Thompson AK
[Ad] Endereço:*Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352; †National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899.
[Ti] Título:Beyond Californium-A Neutron Generator Alternative for Dosimetry and Instrument Calibration in the U.S.
[So] Source:Health Phys;113(3):183-194, 2017 09.
[Is] ISSN:1538-5159
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Evaluations of neutron survey instruments, area monitors, and personal dosimeters rely on reference neutron radiations, which have evolved from the heavy reliance on (α,n) sources to a shared reliance on (α,n) and the spontaneous fission neutrons of californium-252 (Cf). Capable of producing high dose equivalent rates from an almost point source geometry, the characteristics of Cf are generally more favorable when compared to the use of (α,n) and (γ,n) sources or reactor-produced reference neutron radiations. Californium-252 is typically used in two standardized configurations: unmoderated, to yield a fission energy spectrum; or with the capsule placed within a heavy-water moderating sphere to produce a softened spectrum that is generally considered more appropriate for evaluating devices used in nuclear power plant work environments. The U.S. Department of Energy Cf Loan/Lease Program, a longtime origin of affordable Cf sources for research, testing and calibration, was terminated in 2009. Since then, high-activity sources have become increasingly cost-prohibitive for laboratories that formerly benefited from that program. Neutron generators, based on the D-T and D-D fusion reactions, have become economically competitive with Cf and are recognized internationally as important calibration and test standards. Researchers from the National Institute of Standards and Technology and the Pacific Northwest National Laboratory are jointly considering the practicality and technical challenges of implementing neutron generators as calibration standards in the U.S. This article reviews the characteristics of isotope-based neutron sources, possible isotope alternatives to Cf, and the rationale behind the increasing favor of electronically generated neutron options. The evaluation of a D-T system at PNNL has revealed characteristics that must be considered in adapting generators to the task of calibration and testing where accurate determination of a dosimetric quantity is necessary. Finally, concepts are presented for modifying the generated neutron spectra to achieve particular targeted spectra, simulating Cf or workplace environments.
[Mh] Termos MeSH primário: Califórnio/química
Nêutrons
Radiometria/instrumentação
[Mh] Termos MeSH secundário: Calibragem
Aceleradores de Partículas
Estados Unidos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
975X05H15A (Californium)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1097/HP.0000000000000689


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[PMID]:29254593
[Au] Autor:Veselsky T; Novotny J; Pastykova V; Koniarova I
[Ad] Endereço:Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Department of Dosimetry and Application of Ionizing Radiation, Prague, Brehova 78/7, 110 00, Czech Republic; Na Homolce Hospital, Medical Physics Department, Prague, Roentgenova 2/37, 150 30, Czech Republic;
[Ti] Título:Determination of small field synthetic single-crystal diamond detector correction factors for CyberKnife, Leksell Gamma Knife Perfexion and linear accelerator.
[So] Source:Phys Med;44:66-71, 2017 Dec.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements. MATERIALS AND METHODS: Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio M /M with Monte Carlo (MC) based field output factors Ω determined using Dosimetry Diode E or with MC simulation itself. Diode measurements were used for the CyberKnife and Varian Clinac 2100C/D linear accelerator. PTW microDiamond correction factors for Leksell Gamma Knife (LGK) were derived using MC simulated reference values from the manufacturer. RESULTS: PTW microDiamond correction factors for CyberKnife field sizes 25-5 mm were mostly smaller than 1% (except for 2.9% for 5 mm Iris field and 1.4% for 7.5 mm fixed cone field). The correction of 0.1% and 2.0% for 8 mm and 4 mm collimators, respectively, needed to be applied to PTW microDiamond measurements for LGK Perfexion. Finally, PTW microDiamond M /M for the linear accelerator varied from MC corrected Dosimetry Diode data by less than 0.5% (except for 1 × 1 cm field size with 1.3% deviation). CONCLUSIONS: Regarding low resulting correction factor values, the PTW microDiamond detector may be considered an almost ideal tool for relative small field dosimetry in a large variety of stereotactic and radiosurgery treatment devices.
[Mh] Termos MeSH primário: Diamante
Aceleradores de Partículas
Radiocirurgia/instrumentação
[Mh] Termos MeSH secundário: Radiometria
Incerteza
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
7782-40-3 (Diamond)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180130
[Lr] Data última revisão:
180130
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171220
[St] Status:MEDLINE


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[PMID]:29254588
[Au] Autor:Petoukhova A; Rüssel I; Nijst-Brouwers J; van Wingerden K; van Egmond J; Jacobs D; Marinelli A; van der Sijp J; Koper P; Struikmans H
[Ad] Endereço:Haaglanden Medical Center, Department of Medical Physics, Leidschendam, The Netherlands. Electronic address: a.petoukhova@haaglandenmc.nl.
[Ti] Título:In vivo dosimetry with MOSFETs and GAFCHROMIC films during electron IORT for Accelerated Partial Breast Irradiation.
[So] Source:Phys Med;44:26-33, 2017 Dec.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The purpose of this study was to compare the delivered dose to the expected intraoperative radiation therapy (IORT) dose with in vivo dosimetry. For IORT using electrons in accelerated partial breast irradiation, this is especially relevant since a high dose is delivered in a single fraction. METHODS: For 47 of breast cancer patients, in vivo dosimetry was performed with MOSFETs and/or GAFCHROMIC EBT2 films. A total dose of 23.33 Gy at d was given directly after completing the lumpectomy procedure with electron beams generated with an IORT dedicated mobile accelerator. A protection disk was used to shield the thoracic wall. RESULTS: The results of in vivo MOSFET dosimetry for 27 patients and GAFROMIC film dosimetry for 20 patients were analysed. The entry dose for the breast tissue, measured with MOSFETs, (mean value 22.3 Gy, SD 3.4%) agreed within 1.7% with the expected dose (mean value 21.9 Gy). The dose in breast tissue, measured with GAFCHROMIC films (mean value 23.50 Gy) was on average within 0.7% (SD = 3.7%, range -5.5% to 5.6%) of the prescribed dose of 23.33 Gy. CONCLUSIONS: The dose measured with MOSFETs and GAFROMIC EBT2 films agreed well with the expected dose. For both methods, the dose to the thoracic wall, lungs and heart for left sided patents was lower than 2.5 Gy even when 12 MeV was applied. The positioning time of GAFCHROMIC films is negligible and based on our results we recommend its use as a standard tool for patient quality assurance during breast cancer IORT.
[Mh] Termos MeSH primário: Neoplasias da Mama/radioterapia
Elétrons/uso terapêutico
Dosimetria Fotográfica/instrumentação
Metais/química
Óxidos/química
Dosímetros de Radiação
Transistores Eletrônicos
[Mh] Termos MeSH secundário: Neoplasias da Mama/cirurgia
Calibragem
Seres Humanos
Período Intraoperatório
Meia-Idade
Aceleradores de Partículas
Dosagem Radioterapêutica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Metals); 0 (Oxides)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180130
[Lr] Data última revisão:
180130
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171220
[St] Status:MEDLINE


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[PMID]:28886048
[Au] Autor:Nwankwo O; Glatting G; Wenz F; Fleckenstein J
[Ad] Endereço:Department of Radiation Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
[Ti] Título:A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.
[So] Source:PLoS One;12(9):e0183486, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation. MATERIALS AND METHODS: A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses. RESULTS: The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields. CONCLUSION: A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.
[Mh] Termos MeSH primário: Método de Monte Carlo
Aceleradores de Partículas
Fótons
[Mh] Termos MeSH secundário: Algoritmos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170909
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0183486


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[PMID]:28721904
[Au] Autor:Kerns JR; Stingo F; Followill DS; Howell RM; Melancon A; Kry SF
[Ad] Endereço:Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; Imaging and Radiation Oncology Core-Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas; Graduate School of Biomedical Sciences, The University of Texas Health Science Center-Ho
[Ti] Título:Treatment Planning System Calculation Errors Are Present in Most Imaging and Radiation Oncology Core-Houston Phantom Failures.
[So] Source:Int J Radiat Oncol Biol Phys;98(5):1197-1203, 2017 Aug 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The anthropomorphic phantom program at the Houston branch of the Imaging and Radiation Oncology Core (IROC-Houston) is an end-to-end test that can be used to determine whether an institution can accurately model, calculate, and deliver an intensity modulated radiation therapy dose distribution. Currently, institutions that do not meet IROC-Houston's criteria have no specific information with which to identify and correct problems. In the present study, an independent recalculation system was developed to identify treatment planning system (TPS) calculation errors. METHODS AND MATERIALS: A recalculation system was commissioned and customized using IROC-Houston measurement reference dosimetry data for common linear accelerator classes. Using this system, 259 head and neck phantom irradiations were recalculated. Both the recalculation and the institution's TPS calculation were compared with the delivered dose that was measured. In cases in which the recalculation was statistically more accurate by 2% on average or 3% at a single measurement location than was the institution's TPS, the irradiation was flagged as having a "considerable" institutional calculation error. The error rates were also examined according to the linear accelerator vendor and delivery technique. RESULTS: Surprisingly, on average, the reference recalculation system had better accuracy than the institution's TPS. Considerable TPS errors were found in 17% (n=45) of the head and neck irradiations. Also, 68% (n=13) of the irradiations that failed to meet the IROC-Houston criteria were found to have calculation errors. CONCLUSIONS: Nearly 1 in 5 institutions were found to have TPS errors in their intensity modulated radiation therapy calculations, highlighting the need for careful beam modeling and calculation in the TPS. An independent recalculation system can help identify the presence of TPS errors and pass on the knowledge to the institution.
[Mh] Termos MeSH primário: Imagens de Fantasmas/normas
Dosagem Radioterapêutica/normas
Planejamento da Radioterapia Assistida por Computador/normas
Radioterapia de Intensidade Modulada/normas
[Mh] Termos MeSH secundário: Algoritmos
Calibragem
Cabeça
Erros Médicos/estatística & dados numéricos
Aceleradores de Partículas/normas
Imagens de Fantasmas/estatística & dados numéricos
Planejamento da Radioterapia Assistida por Computador/métodos
Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos
Radioterapia de Intensidade Modulada/estatística & dados numéricos
Padrões de Referência
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170907
[Lr] Data última revisão:
170907
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170720
[St] Status:MEDLINE


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[PMID]:28639140
[Au] Autor:Endo S; Sato H; Shimazaki T; Nakajima E; Kotani K; Suda M; Hamano T; Kajimoto T; Tanaka K; Hoshi M
[Ad] Endereço:Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan. endos@hiroshima-u.ac.jp.
[Ti] Título:Determination of the thermal and epithermal neutron sensitivities of an LBO chamber.
[So] Source:Radiat Environ Biophys;56(3):269-276, 2017 Aug.
[Is] ISSN:1432-2099
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:An LBO (Li B O ) walled ionization chamber was designed to monitor the epithermal neutron fluence in boron neutron capture therapy clinical irradiation. The thermal and epithermal neutron sensitivities of the device were evaluated using accelerator neutrons from the Be(d, n) reaction at a deuteron energy of 4 MeV (4 MeV d-Be neutrons). The response of the chamber in terms of the electric charge induced in the LBO chamber was compared with the thermal and epithermal neutron fluences measured using the gold-foil activation method. The thermal and epithermal neutron sensitivities obtained were expressed in units of pC cm , i.e., from the chamber response divided by neutron fluence (cm ). The measured LBO chamber sensitivities were 2.23 × 10 ± 0.34 × 10 (pC cm ) for thermal neutrons and 2.00 × 10 ± 0.12 × 10 (pC cm ) for epithermal neutrons. This shows that the LBO chamber is sufficiently sensitive to epithermal neutrons to be useful for epithermal neutron monitoring in BNCT irradiation.
[Mh] Termos MeSH primário: Compostos de Boro
Nêutrons
Radiometria/instrumentação
Temperatura Ambiente
[Mh] Termos MeSH secundário: Aceleradores de Partículas
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Boron Compounds)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170912
[Lr] Data última revisão:
170912
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170623
[St] Status:MEDLINE
[do] DOI:10.1007/s00411-017-0700-y


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[PMID]:28587053
[Au] Autor:O'Daniel JC; Yin FF
[Ad] Endereço:Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina. Electronic address: jennifer.odaniel@duke.edu.
[Ti] Título:Quantitative Approach to Failure Mode and Effect Analysis for Linear Accelerator Quality Assurance.
[So] Source:Int J Radiat Oncol Biol Phys;98(1):56-62, 2017 May 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To determine clinic-specific linear accelerator quality assurance (QA) TG-142 test frequencies, to maximize physicist time efficiency and patient treatment quality. METHODS AND MATERIALS: A novel quantitative approach to failure mode and effect analysis is proposed. Nine linear accelerator-years of QA records provided data on failure occurrence rates. The severity of test failure was modeled by introducing corresponding errors into head and neck intensity modulated radiation therapy treatment plans. The relative risk of daily linear accelerator QA was calculated as a function of frequency of test performance. RESULTS: Although the failure severity was greatest for daily imaging QA (imaging vs treatment isocenter and imaging positioning/repositioning), the failure occurrence rate was greatest for output and laser testing. The composite ranking results suggest that performing output and lasers tests daily, imaging versus treatment isocenter and imaging positioning/repositioning tests weekly, and optical distance indicator and jaws versus light field tests biweekly would be acceptable for non-stereotactic radiosurgery/stereotactic body radiation therapy linear accelerators. CONCLUSIONS: Failure mode and effect analysis is a useful tool to determine the relative importance of QA tests from TG-142. Because there are practical time limitations on how many QA tests can be performed, this analysis highlights which tests are the most important and suggests the frequency of testing based on each test's risk priority number.
[Mh] Termos MeSH primário: Análise de Falha de Equipamento/métodos
Neoplasias de Cabeça e Pescoço/radioterapia
Análise do Modo e do Efeito de Falhas na Assistência à Saúde
Aceleradores de Partículas/normas
Garantia da Qualidade dos Cuidados de Saúde/métodos
Erros de Configuração em Radioterapia
[Mh] Termos MeSH secundário: Fracionamento de Dose
Análise de Falha de Equipamento/estatística & dados numéricos
Seres Humanos
Aceleradores de Partículas/estatística & dados numéricos
Controle de Qualidade
Radioterapia (Especialidade)/instrumentação
Radioterapia de Intensidade Modulada/instrumentação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170721
[Lr] Data última revisão:
170721
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170608
[St] Status:MEDLINE



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BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde