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[PMID]:27866897
[Au] Autor:Figueroa RG; Santibáñez M; Valente M
[Ad] Endereço:Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile; Centro de Física e Ingeniería en Medicina - CFIM, Universidad de La Frontera, Temuco, Chile. Electronic address: rodolfo.figueroa@ufrontera.cl.
[Ti] Título:Dosimetric and bremsstrahlung performance of a single convergent beam for teletherapy device.
[So] Source:Phys Med;32(12):1489-1494, 2016 Dec.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:The present work investigates preliminary feasibility and characteristics of a new type of radiation therapy modality based on a single convergent beam of photons. The proposal consists of the design of a device capable of generating convergent X-ray beams useful for radiotherapy. The main goal is to achieve high concentrated dose delivery. The first step is an analytical approach in order to characterize the dosimetric performance of the hypothetical convergent photon beam. Then, the validated FLUKA Monte Carlo main code is used to perform complete radiation transport to account also for scattering effects. The proposed method for producing convergent X-rays is mainly based on the bremsstrahlung effect. Hence the operating principle of the proposed device is described in terms of bremsstrahlung production. The work is mainly devoted characterizing the effect on the bremsstrahlung yield due to accessories present in the device, like anode material and geometry, filtration and collimation systems among others. The results obtained for in-depth dose distributions, by means of analytical and stochastic approaches, confirm the presence of a high dose concentration around the irradiated target, as expected. Moreover, it is shown how this spot of high dose concentration depends upon the relevant physical properties of the produced convergent photon beam. In summary, the proposed design for producing single convergent X-rays attained satisfactory performance for achieving high dose concentration around small targets depending on beam spot size that may be used for some applications in radiotherapy, like radiosurgery.
[Mh] Termos MeSH primário: Teleterapia por Radioisótopo/instrumentação
[Mh] Termos MeSH secundário: Estudos de Viabilidade
Método de Monte Carlo
Óptica e Fotônica
Fótons/uso terapêutico
Radiometria
Dosagem Radioterapêutica
Espalhamento de Radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170331
[Lr] Data última revisão:
170331
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161122
[St] Status:MEDLINE


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[PMID]:27538269
[Au] Autor:Muhammad W; Ullah A; Mahmood K; Matiullah
[Ti] Título:Assessment of national dosimetry quality audits results for teletherapy machines from 1989 to 2015.
[So] Source:J Appl Clin Med Phys;17(2):145-152, 2016.
[Is] ISSN:1526-9914
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The purpose of this study was to ensure accuracy in radiation dose delivery, external dosimetry quality audit has an equal importance with routine dosimetry performed at clinics. To do so, dosimetry quality audit was organized by the Secondary Standard Dosimetry Laboratory (SSDL) of Pakistan Institute of Nuclear Science and Technology (PINSTECH) at the national level to investigate and minimize uncertainties involved in the measurement of absorbed dose, and to improve the accuracy of dose measurement at different radiotherapy hospitals. A total of 181 dosimetry quality audits (i.e., 102 of Co-60 and 79 of linear accelerators) for teletherapy units installed at 22 different sites were performed from 1989 to 2015. The percent deviation between users' calculated/stated dose and evaluated dose (in the result of on-site dosimetry visits) were calculated and the results were analyzed with respect to the limits of ± 2.5% (ICRU "optimal model") ± 3.0% (IAEA on-site dosimetry visits limit) and ± 5.0% (ICRU minimal or "lowest acceptable" model). The results showed that out of 181 total on-site dosimetry visits, 20.44%, 16.02%, and 4.42% were out of acceptable limits of ± 2.5% ± 3.0%, and ± 5.0%, respectively. The importance of a proper ongoing quality assurance program, recommendations of the followed protocols, and properly calibrated thermometers, pressure gauges, and humidity meters at radiotherapy hospitals are essential in maintaining consistency and uniformity of absorbed dose measurements for precision in dose delivery.
[Mh] Termos MeSH primário: Neoplasias/radioterapia
Garantia da Qualidade dos Cuidados de Saúde/normas
Controle de Qualidade
Teleterapia por Radioisótopo/instrumentação
Planejamento da Radioterapia Assistida por Computador/normas
Radioterapia/normas
Dosimetria Termoluminescente/normas
[Mh] Termos MeSH secundário: Calibragem
Auditoria Clínica
Hospitais
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1701
[Cu] Atualização por classe:170907
[Lr] Data última revisão:
170907
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160820
[St] Status:MEDLINE
[do] DOI:10.1120/jacmp.v17i2.5984


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[PMID]:26755076
[Au] Autor:Merna C; Rwigema JC; Cao M; Wang PC; Kishan AU; Michailian A; Lamb J; Sheng K; Agazaryan N; Low DA; Kupelian P; Steinberg ML; Lee P
[Ad] Endereço:Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA.
[Ti] Título:A treatment planning comparison between modulated tri-cobalt-60 teletherapy and linear accelerator-based stereotactic body radiotherapy for central early-stage non-small cell lung cancer.
[So] Source:Med Dosim;41(1):87-91, 2016.
[Is] ISSN:1873-4022
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We evaluated the feasibility of planning stereotactic body radiotherapy (SBRT) for large central early-stage non-small cell lung cancer with a tri-cobalt-60 (tri-(60)Co) system equipped with real-time magnetic resonance imaging (MRI) guidance, as compared to linear accelerator (LINAC)-based SBRT. In all, 20 patients with large central early-stage non-small cell lung cancer who were treated between 2010 and 2015 with LINAC-based SBRT were replanned using a tri-(60)Co system for a prescription dose of 50Gy in 4 fractions. Doses to organs at risk were evaluated based on established MD Anderson constraints for central lung SBRT. R100 values were calculated as the total tissue volume receiving 100% of the dose (V100) divided by the planning target volume and compared to assess dose conformity. Dosimetric comparisons between LINAC-based and tri-(60)Co SBRT plans were performed using Student׳s t-test and Wilcoxon Ranks test. Blinded reviews by radiation oncologists were performed to assess the suitability of both plans for clinical delivery. The mean planning target volume was 48.3cc (range: 12.1 to 139.4cc). Of the tri-(60)Co SBRT plans, a mean 97.4% of dosimetric parameters per patient met MD Anderson dose constraints, whereas a mean 98.8% of dosimetric parameters per patient were met with LINAC-based SBRT planning (p = 0.056). R100 values were similar between both plans (1.20 vs 1.21, p = 0.79). Upon blinded review by 4 radiation oncologists, an average of 90% of the tri-(60)Co SBRT plans were considered acceptable for clinical delivery compared with 100% of the corresponding LINAC-based SBRT plans (p = 0.17). SBRT planning using the tri-(60)Co system with built-in MRI is feasible and achieves clinically acceptable plans for most central lung patients, with similar target dose conformity and organ at risk dosimetry. The added benefit of real-time MRI-guided therapy may further optimize tumor targeting while improving normal tissue sparing, which warrants further investigation in a prospective feasibility clinical trial.
[Mh] Termos MeSH primário: Carcinoma Pulmonar de Células não Pequenas/radioterapia
Radioisótopos de Cobalto/uso terapêutico
Teleterapia por Radioisótopo
Radiocirurgia
Planejamento da Radioterapia Assistida por Computador
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Feminino
Seres Humanos
Masculino
Meia-Idade
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cobalt Radioisotopes)
[Em] Mês de entrada:1612
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160113
[St] Status:MEDLINE


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[PMID]:26431578
[Au] Autor:Gul A; Liaquat M; Kanwal A; Abbasi NZ; Kakakhel MB; Ali A
[Ad] Endereço:Institute of Nuclear Medicine, Oncology and Radiotherapy (INOR), Abbottabad, Pakistan. Electronic address: attiagul@gmail.com.
[Ti] Título:Assessment of dose error due to nylon mesh of treatment couch.
[So] Source:Phys Med;31(8):1080-1084, 2015 Dec.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:PURPOSE: This study aims at the assessment of dose error in patients undergoing radiotherapy due to treatment couch of Co-60 teletherapy unit. MATERIALS AND METHODS: In this study beam attenuation due to treatment couch of Co-60 unit was measured in air for different gantry angles and field sizes. Polymethylmethacrylate (PMMA) phantom was used to estimate the effect of depth on attenuation. Impact of couch on surface dose was also evaluated. RESULTS: Beam attenuation due to couch was in the range of 0.5-28% for different gantry angles with standard field size of 10 × 10 cm(2) with optimum position of metallic cranks. Maximum attenuation (29%) was observed with smallest field size i.e. 5 × 5 cm(2). Beam attenuation has been found higher in phantom as compared to that in air However, no particular trend of attenuation has been noted with varying depth of phantom. A 6% increase in surface dose has also been observed due to couch insertion for normal beam incidence. Maximum error of 80% is also note-worthy for most unfavorable situation of irradiation at 180 degree through the metallic cranks. CONCLUSION: It has been determined that ignoring the treatment couch and its accessories can result in dose error of 0.5-80%, depending on gantry angle, field size and position of couch accessories. Therefore, consideration of dose error due to couch during treatment planning is recommended.
[Mh] Termos MeSH primário: Nylons
Dose de Radiação
Teleterapia por Radioisótopo/instrumentação
Erros de Configuração em Radioterapia
[Mh] Termos MeSH secundário: Dosagem Radioterapêutica
Pele/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Nylons)
[Em] Mês de entrada:1609
[Cu] Atualização por classe:171017
[Lr] Data última revisão:
171017
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151004
[St] Status:MEDLINE


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[PMID]:26348025
[Au] Autor:Figueroa RG; Valente M
[Ad] Endereço:Universidad de La Frontera, Francisco Salazar 1145, Temuco, IX Región, Chile.
[Ti] Título:Physical characterization of single convergent beam device for teletherapy: theoretical and Monte Carlo approach.
[So] Source:Phys Med Biol;60(18):7191-206, 2015 Sep 21.
[Is] ISSN:1361-6560
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The main purpose of this work is to determine the feasibility and physical characteristics of a new teletherapy device of radiation therapy based on the application of a convergent x-ray beam of energies like those used in radiotherapy providing highly concentrated dose delivery to the target. We have denominated it Convergent Beam Radio Therapy (CBRT). Analytical methods are developed first in order to determine the dosimetry characteristic of an ideal convergent photon beam in a hypothetical water phantom. Then, using the PENELOPE Monte Carlo code, a similar convergent beam that is applied to the water phantom is compared with that of the analytical method. The CBRT device (Converay(®)) is designed to adapt to the head of LINACs. The converging beam photon effect is achieved thanks to the perpendicular impact of LINAC electrons on a large thin spherical cap target where Bremsstrahlung is generated (high-energy x-rays). This way, the electrons impact upon various points of the cap (CBRT condition), aimed at the focal point. With the X radiation (Bremsstrahlung) directed forward, a system of movable collimators emits many beams from the output that make a virtually definitive convergent beam. Other Monte Carlo simulations are performed using realistic conditions. The simulations are performed for a thin target in the shape of a large, thin, spherical cap, with an r radius of around 10-30 cm and a curvature radius of approximately 70 to 100 cm, and a cubed water phantom centered in the focal point of the cap. All the interaction mechanisms of the Bremsstrahlung radiation with the phantom are taken into consideration for different energies and cap thicknesses. Also, the magnitudes of the electric and/or magnetic fields, which are necessary to divert clinical-use electron beams (0.1 to 20 MeV), are determined using electromagnetism equations with relativistic corrections. This way the above-mentioned beam is manipulated and guided for its perpendicular impact upon the spherical cap. The first results that were achieved show in-depth dose peaks, having shapes qualitatively similar to those from hadrontherapy techniques. The obtained results demonstrate that in-depth dose peaks are generated at the focus point or isocenter. These results are consistent with those obtained with Monte Carlo codes. The peak-focus is independent of the energy of the photon beam, though its intensity is not. The realistic results achieved with the Monte Carlo code show that the Bremsstrahlung generated on the thin cap is mainly directed towards the focus point. The aperture angle at each impact point depends primarily on the energy beam, the atomic number Z and the thickness of the target. There is also a poly-collimator coaxial to the cap or ring with many holes, permitting a clean convergent-exit x-ray beam with a dose distribution that is similar to the ideal case. The electric and magnetic fields needed to control the deflection of the electron beams in the CBRT geometry are highly feasible using specially designed electric and/or magnetic devices that, respectively, have voltage and current values that are technically achievable. However, it was found that magnetic devices represent a more suitable option for electron beam control, especially at high energies. The main conclusion is that the development of such a device is feasible. Due to its features, this technology might be considered a powerful new tool for external radiotherapy with photons.
[Mh] Termos MeSH primário: Modelos Teóricos
Método de Monte Carlo
Aceleradores de Partículas/instrumentação
Imagens de Fantasmas
Fótons/uso terapêutico
Teleterapia por Radioisótopo/instrumentação
Teleterapia por Radioisótopo/métodos
[Mh] Termos MeSH secundário: Fenômenos Eletromagnéticos
Elétrons
Desenho de Equipamento
Seres Humanos
Radiometria/métodos
Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1604
[Cu] Atualização por classe:150909
[Lr] Data última revisão:
150909
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150909
[St] Status:MEDLINE
[do] DOI:10.1088/0031-9155/60/18/7191


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[PMID]:25863565
[Au] Autor:Laé M; Lebel A; Hamel-Viard F; Asselain B; Trassard M; Sastre X; Kirova YM
[Ad] Endereço:Département de biologie des tumeurs, 26, rue d'Ulm, 75005 Paris, France.
[Ti] Título:Can c-myc amplification reliably discriminate postradiation from primary angiosarcoma of the breast?
[So] Source:Cancer Radiother;19(3):168-74, 2015 May.
[Is] ISSN:1769-6658
[Cp] País de publicação:France
[La] Idioma:eng
[Ab] Resumo:PURPOSE: Breast angiosarcomas are rare vascular malignancies that arise secondary to irradiation or de novo as primary tumours. The aim of this study is to know whether c-myc amplification can reliably discriminate these two entities. MATERIEL AND METHODS: Forty-seven patients treated for breast angiosarcomas were studied. Thirty-two patients were diagnosed with postradiation angiosarcomas after breast cancer treatment and 15 patients with primary angiosarcomas. Interphase fluorescence in situ hybridization (FISH) was performed by hybridization of probes covering C-MYC (chromosome 8q24.21) and CEP8 on tissue sections. RESULTS: Amplification (5- to 20-fold) of the c-myc oncogene was found in all breast radiation-induced angiosarcomas (32 tumours) but in none of the 15 primary angiosarcomas except one (7%). CONCLUSION: This study reinforces that there are true pathogenetic differences between the two types of breast angiosarcomas which are morphologically indistinguishable. These data point the pathways preferentially involved in the pathogenesis of post radiation angiosarcomas of the breast and may provide the basis for an additional targeted therapy.
[Mh] Termos MeSH primário: Neoplasias da Mama/diagnóstico
Amplificação de Genes
Genes myc
Hemangiossarcoma/diagnóstico
Neoplasias Induzidas por Radiação/diagnóstico
Segunda Neoplasia Primária/diagnóstico
Teleterapia por Radioisótopo/efeitos adversos
[Mh] Termos MeSH secundário: Adulto
Idoso
Idoso de 80 Anos ou mais
Neoplasias da Mama/química
Neoplasias da Mama/genética
Neoplasias da Mama/radioterapia
Neoplasias da Mama/cirurgia
Carcinoma Ductal de Mama/radioterapia
Carcinoma Ductal de Mama/cirurgia
Cromossomos Humanos Par 8/genética
Cromossomos Humanos Par 8/ultraestrutura
Terapia Combinada
DNA de Neoplasias/genética
Diagnóstico Diferencial
Feminino
Hemangiossarcoma/química
Hemangiossarcoma/genética
Seres Humanos
Hibridização in Situ Fluorescente
Interfase
Excisão de Linfonodo
Mastectomia
Meia-Idade
Neoplasias Induzidas por Radiação/química
Neoplasias Induzidas por Radiação/genética
Segunda Neoplasia Primária/química
Segunda Neoplasia Primária/genética
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (DNA, Neoplasm)
[Em] Mês de entrada:1507
[Cu] Atualização por classe:150522
[Lr] Data última revisão:
150522
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150413
[St] Status:MEDLINE


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[PMID]:25562678
[Au] Autor:Nogueira LB; Silva HL; de Campos TP
[Ad] Endereço:Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte, Brazil. Electronic address: lucibn19@yahoo.com.br.
[Ti] Título:Experimental dosimetry in conformal breast teletherapy compared with the planning system.
[So] Source:Appl Radiat Isot;97:93-100, 2015 Mar.
[Is] ISSN:1872-9800
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The objective of this study was to compare and analyse the absorbed dose profiles from the conformal radiotherapy planning and experimental dosimetry taken in a breast anthropomorphic and anthropometric phantom. Conformal radiotherapy planning was elaborated in the Treatment Planning System (TPS). EBT2 Gafchromic radiochromic films were applied as dosimeters, positioned internally and superficially in the breast phantom. The standard radiation protocol was applied in the breast phantom. The films were digitalised, and their responses were analysed in RGB. The optical densities were processed, reproducing the spatial dose distribution.
[Mh] Termos MeSH primário: Neoplasias da Mama/radioterapia
Teleterapia por Radioisótopo/métodos
Planejamento da Radioterapia Assistida por Computador/métodos
Radioterapia Conformacional/métodos
[Mh] Termos MeSH secundário: Neoplasias da Mama/diagnóstico por imagem
Calibragem
Feminino
Dosimetria Fotográfica/estatística & dados numéricos
Seres Humanos
Imagens de Fantasmas
Teleterapia por Radioisótopo/estatística & dados numéricos
Dosagem Radioterapêutica
Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos
Radioterapia Conformacional/estatística & dados numéricos
Tomografia Computadorizada por Raios X
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1511
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150107
[St] Status:MEDLINE


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[PMID]:25671926
[Au] Autor:Memon SA; Cheema AA; Laghari NA; Mangi FH
[Ti] Título:Dose measurement of cobalt-60 radiotherapy beams in treatment fields.
[So] Source:J Ayub Med Coll Abbottabad;26(3):279-82, 2014 Jul-Sep.
[Is] ISSN:1025-9589
[Cp] País de publicação:Pakistan
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Radiation-therapy is a complex process with multiple steps, each of which has an impact on the quality of treatment. Accurate dosimetry is a critical step during the radiotherapy of cancer patients.The aim of the present study was to measure and evaluate the doses of two cobalt- 60 (60Co) teletherapy units GWXJ80 of NPIC China and Theratron 780 of AECL Canada at various points within fields for different field sizes. METHODS: This cross-sectional descriptive study was done to measure the 60Co doses in the treatment fields.The dose measurements were done in air and 30x30x30 cm3 Phantom at 80 cm SSD by using calibrated NE 2570 Farmer Electrometer & NE 2571 Farmer Ionization Chamber and percentage of doses were calculated. RESULTS: The results showed that 60% central area of all fields ranging from 100-98.79% and 100-96.12% for GWXJ80 in the air and phantom, whereas for Theratron 780, they were ranging from 100-98.50% and 100-96.45% in air and phantom respectively. The percentages of doses at the edges for GWXJ80 and Theratron 780 in the air were 75.39-38.66% & 85.65-46.47% respectively and they were 82.22-40.39% & 49.05-24.55% respectively in phantom. CONCLUSIONS: The doses within 60% central area of fields in air were higher than phantom for both teletherapy units. The doses at field edges in air were lower in GWXJ80 than Theratron 780 whereas in phantom they were vice versa. But all were in the acceptable range as recommended by International Commission on Radiation Units and Measurements.
[Mh] Termos MeSH primário: Radioisótopos de Cobalto/uso terapêutico
Dose de Radiação
Teleterapia por Radioisótopo/instrumentação
[Mh] Termos MeSH secundário: Ar
Estudos Transversais
Dosagem Radioterapêutica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cobalt Radioisotopes)
[Em] Mês de entrada:1503
[Cu] Atualização por classe:150212
[Lr] Data última revisão:
150212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150213
[St] Status:MEDLINE


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[PMID]:25312317
[Au] Autor:Luna-Martínez J; Molina-Ramírez D; Mata-Quintero CJ; García-Arrona LR; Peña-Rosas DP; Mondragón-Pinzón EE
[Ad] Endereço:Servicio de Cirugía General, Hospital Central Sur de Alta Especialidad, PEMEX, México DF, Mexico.
[Ti] Título:[Myxoid liposarcoma of the anterior mediastinum. A case report and bibliography review].
[Ti] Título:Liposarcoma mixoide de mediastino anterior. Reporte de caso y revisión de la bibliografía..
[So] Source:Cir Cir;82(2):177-82, 2014 Mar-Apr.
[Is] ISSN:0009-7411
[Cp] País de publicação:Spain
[La] Idioma:spa
[Ab] Resumo:UNLABELLED: Five cases per year. Of those cases 50% are located in the extremities and 40% are located in the trunk and retroperitoneum. Primary mediastinal liposarcomas represent less than 1% of mediastinal tumors. CLINICAL CASE: A 53 year old female, native and resident of Tabasco, with a history of anterior mediastinal tumor was treated with resection at the National Institute of Cancerology about 16 years ago with histopathological diagnosis of pleomorphic liposarcoma. She started her condition with chest pain, cough and hyaline expectoration, managed as pneumonia in her unit. Other symptoms occurred, moderate exertion dyspnea and edema of lower limbs, chest computed tomography prompted for documenting mediastinal tumor measured to be 9 × 9 cm and sent to our unit which is managed with resection.
[Mh] Termos MeSH primário: Lipossarcoma Mixoide/cirurgia
Neoplasias do Mediastino/terapia
Recidiva Local de Neoplasia/cirurgia
Segunda Neoplasia Primária/cirurgia
[Mh] Termos MeSH secundário: Terapia Combinada
Diagnóstico Diferencial
Dispneia/etiologia
Feminino
Seres Humanos
Lipossarcoma/patologia
Lipossarcoma/radioterapia
Lipossarcoma/cirurgia
Lipossarcoma Mixoide/complicações
Lipossarcoma Mixoide/diagnóstico
Metástase Linfática
Neoplasias do Mediastino/complicações
Neoplasias do Mediastino/diagnóstico
Meia-Idade
Recidiva Local de Neoplasia/diagnóstico
Segunda Neoplasia Primária/diagnóstico
Pneumonia/diagnóstico
Gravidez
Complicações Neoplásicas na Gravidez/radioterapia
Complicações Neoplásicas na Gravidez/cirurgia
Teleterapia por Radioisótopo
[Pt] Tipo de publicação:CASE REPORTS; ENGLISH ABSTRACT; JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1506
[Cu] Atualização por classe:141014
[Lr] Data última revisão:
141014
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141015
[St] Status:MEDLINE


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[PMID]:24599345
[Au] Autor:Janiszewska M; Polaczek-Grelik K; Raczkowski M; Szafron B; Konefal A; Zipper W
[Ad] Endereço:Medical Physics Department, Lower Silesian Oncology Center, Hiszfeld Square 12, 53-413, Wroclaw, Poland, janiszewska.m@dco.com.pl.
[Ti] Título:Secondary radiation dose during high-energy total body irradiation.
[So] Source:Strahlenther Onkol;190(5):459-66, 2014 May.
[Is] ISSN:1439-099X
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:AIM: The goal of this work was to assess the additional dose from secondary neutrons and γ-rays generated during total body irradiation (TBI) using a medical linac X-ray beam. BACKGROUND: Nuclear reactions that occur in the accelerator construction during emission of high-energy beams in teleradiotherapy are the source of secondary radiation. Induced activity is dependent on the half-lives of the generated radionuclides, whereas neutron flux accompanies the treatment process only. MATERIALS AND METHODS: The TBI procedure using a 18 MV beam (Clinac 2100) was considered. Lateral and anterior-posterior/posterior-anterior fractions were investigated during delivery of 2 Gy of therapeutic dose. Neutron and photon flux densities were measured using neutron activation analysis (NAA) and semiconductor spectrometry. The secondary dose was estimated applying the fluence-to-dose conversion coefficients. RESULTS: The main contribution to the secondary dose is associated with fast neutrons. The main sources of γ-radiation are the following: (56)Mn in the stainless steel and (187)W of the collimation system as well as positron emitters, activated via (n,γ) and (γ,n) processes, respectively. In addition to 12 Gy of therapeutic dose, the patient could receive 57.43 mSv in the studied conditions, including 4.63 µSv from activated radionuclides. CONCLUSION: Neutron dose is mainly influenced by the time of beam emission. However, it is moderated by long source-surface distances (SSD) and application of plexiglass plates covering the patient body during treatment. Secondary radiation gives the whole body a dose, which should be taken into consideration especially when one fraction of irradiation does not cover the whole body at once.
[Mh] Termos MeSH primário: Nêutrons Rápidos/uso terapêutico
Raios gama/uso terapêutico
Neoplasias/radioterapia
Teleterapia por Radioisótopo/métodos
Radioterapia de Alta Energia/métodos
Irradiação Corporal Total/métodos
[Mh] Termos MeSH secundário: Fracionamento de Dose
Física Sanitária
Seres Humanos
Análise de Ativação de Nêutrons
Teleterapia por Radioisótopo/instrumentação
Radiometria
Dosagem Radioterapêutica
Radioterapia de Alta Energia/instrumentação
Análise Espectral
Irradiação Corporal Total/instrumentação
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1406
[Cu] Atualização por classe:170916
[Lr] Data última revisão:
170916
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140307
[St] Status:MEDLINE
[do] DOI:10.1007/s00066-014-0635-z



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