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Pesquisa : G09.772.705.349 [Categoria DeCS]
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[PMID]:28463165
[Au] Autor:Li G; Wei J; Kadbi M; Moody J; Sun A; Zhang S; Markova S; Zakian K; Hunt M; Deasy JO
[Ad] Endereço:Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York. Electronic address: lig2@mskcc.org.
[Ti] Título:Novel Super-Resolution Approach to Time-Resolved Volumetric 4-Dimensional Magnetic Resonance Imaging With High Spatiotemporal Resolution for Multi-Breathing Cycle Motion Assessment.
[So] Source:Int J Radiat Oncol Biol Phys;98(2):454-462, 2017 06 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To develop and evaluate a super-resolution approach to reconstruct time-resolved 4-dimensional magnetic resonance imaging (TR-4DMRI) with a high spatiotemporal resolution for multi-breathing cycle motion assessment. METHODS AND MATERIALS: A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board-approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm ) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm ). To examine the image fidelity of 3D cine and super-resolution TR-4DMRI, a mobile gel phantom with multi-internal targets was scanned at 3 speeds and compared with the 3D static image. Image similarity among 3D cine, 4DMRI, and 3D static was evaluated visually using difference image and quantitatively using voxel intensity correlation and Dice index (phantom only). Multi-breathing-cycle waveforms were extracted and compared in both phantom and volunteer images using the 3D cine as the references. RESULTS: Mild imaging artifacts were found in the 3D cine and TR-4DMRI of the mobile gel phantom with a Dice index of >0.95. Among 7 volunteers, the super-resolution TR-4DMRI yielded high voxel-intensity correlation (0.92 ± 0.05) and low voxel-intensity difference (<0.05). The detected motion differences between TR-4DMRI and 3D cine were -0.2 ± 0.5 mm (phantom) and -0.2 ± 1.9 mm (diaphragms). CONCLUSION: Super-resolution TR-4DMRI has been reconstructed with adequate temporal (2 Hz) and spatial (2 × 2 × 2 mm ) resolutions. Further TR-4DMRI characterization and improvement are necessary before clinical applications. Multi-breathing cycles can be examined, providing patient-specific breathing irregularities and motion statistics for future 4D radiation therapy.
[Mh] Termos MeSH primário: Suspensão da Respiração
Aumento da Imagem/métodos
Imagem Tridimensional/métodos
Imagem Cinética por Ressonância Magnética/métodos
Movimento
Respiração
[Mh] Termos MeSH secundário: Artefatos
Análise de Fourier
Seres Humanos
Imagem Tridimensional/normas
Imagem Cinética por Ressonância Magnética/normas
Movimento (Física)
Imagens de Fantasmas
[Pt] Tipo de publicação:JOURNAL ARTICLE; VALIDATION STUDIES; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180228
[Lr] Data última revisão:
180228
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


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[PMID]:29390488
[Au] Autor:Liu M; Liu W; Li H; Shu X; Tao X; Zhai Z
[Ad] Endereço:Department of Radiology.
[Ti] Título:Evaluation of takayasu arteritis with delayed contrast-enhanced MR imaging by a free-breathing 3D IR turbo FLASH.
[So] Source:Medicine (Baltimore);96(51):e9284, 2017 Dec.
[Is] ISSN:1536-5964
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The primary aim of our case-control study was to observe delayed contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with Takayasu arteritis (TA) in comparison with magnetic resonance angiography (MRA). Twenty-seven patients including 15 with active TA and 12 with stable TA who underwent both aortic MRA and DCE-MRI were included. A total of 27 sex- and age-matched healthy volunteers were enrolled as the control group. MRA were obtained with T1WI-volume-interpolated breath-hold examination sequence or fast low-angle shot (FLASH) sequence. DCE-MRI was acquired with a free-breathing three-dimensional inversion recovery Turbo fast low-angle shot (3D IR Turbo FLASH). Neither stenosis nor delayed enhancement of arterial wall was shown in the control group. In patients with stable TA, arterial stenosis was observed on MRA. On DCE-MR, delayed enhancement of arterial walls could be observed in the active TA group but not in the stable TA group or the control group. Stenotic arteries on MRA were comparable in the active TA and stable TA (χ = 2.70, P = .259); however, delayed enhancement of arterial walls in the active-TA group were more than those in the stable group (χ = 27.00, P < .001). Our results suggest that DCE-MRI with the free-breathing 3D IR Turbo FLASH sequence could assess TA and delayed enhancement on DCE-MRI is one characteristics of the active TA.
[Mh] Termos MeSH primário: Imagem Tridimensional
Angiografia por Ressonância Magnética/métodos
Intensificação de Imagem Radiográfica/métodos
Arterite de Takayasu/diagnóstico por imagem
[Mh] Termos MeSH secundário: Adulto
Suspensão da Respiração
Estudos de Casos e Controles
Meios de Contraste
Feminino
Seres Humanos
Masculino
Sensibilidade e Especificidade
Arterite de Takayasu/fisiopatologia
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; OBSERVATIONAL STUDY
[Nm] Nome de substância:
0 (Contrast Media)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:180203
[St] Status:MEDLINE
[do] DOI:10.1097/MD.0000000000009284


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[PMID]:28464744
[Au] Autor:Gorgisyan J; Perrin R; Lomax AJ; Persson GF; Josipovic M; Engelholm SA; Weber DC; Munck Af Rosenschold P
[Ad] Endereço:a Paul Scherrer Institute , Villigen PSI , Switzerland.
[Ti] Título:Impact of beam angle choice on pencil beam scanning breath-hold proton therapy for lung lesions.
[So] Source:Acta Oncol;56(6):853-859, 2017 Jun.
[Is] ISSN:1651-226X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:INTRODUCTION: The breath-hold technique inter alia has been suggested to mitigate the detrimental effect of motion on pencil beam scanned (PBS) proton therapy dose distributions. The aim of this study was to evaluate the robustness of incident proton beam angles to day-to-day anatomical variations in breath-hold. MATERIALS AND METHODS: Single field PBS plans at five degrees increments in the transversal plane were made and water-equivalent path lengths (WEPLs) were derived on the planning breath-hold CT (BHCT) for 30 patients diagnosed with locally-advanced non-small cell lung cancer (NSCLC), early stage NSCLC or lung metastasis. Our treatment planning system was subsequently used to recalculate the plans and derive WEPL on a BHCT scan acquired at the end of the treatment. Changes to the V , D and mean target dose were evaluated. RESULTS: The difference in WEPL as a function of the beam angle was highly patient specific, with a median of 3.3 mm (range: 0.0-41.1 mm). Slightly larger WEPL differences were located around the lateral or lateral anterior/posterior beam angles. Linear models revealed that changes in dose were associated to the changes in WEPL and the tumor baseline shift (p < 0.05). CONCLUSIONS: WEPL changes and tumor baseline shift can serve as reasonable surrogates for dosimetric uncertainty of the target coverage and are well-suited for routine evaluation of plan robustness. The two lateral beam angles are not recommended to use for PBS proton therapy of lung cancer patients treated in breath-hold, due to the poor robustness for several of the patients evaluated.
[Mh] Termos MeSH primário: Suspensão da Respiração
Carcinoma Pulmonar de Células não Pequenas/radioterapia
Neoplasias Pulmonares/radioterapia
Movimento/efeitos da radiação
Terapia com Prótons
Planejamento da Radioterapia Assistida por Computador/métodos
[Mh] Termos MeSH secundário: Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem
Estudos de Coortes
Fracionamento de Dose
Feminino
Tomografia Computadorizada Quadridimensional
Seres Humanos
Processamento de Imagem Assistida por Computador/métodos
Neoplasias Pulmonares/diagnóstico por imagem
Masculino
Dosagem Radioterapêutica
Radioterapia de Intensidade Modulada/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180213
[Lr] Data última revisão:
180213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170504
[St] Status:MEDLINE
[do] DOI:10.1080/0284186X.2017.1287950


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[PMID]:29205080
[Au] Autor:Berg M; Lorenzen EL; Jensen I; Thomsen MS; Lutz CM; Refsgaard L; Nissen HD; Offersen BV
[Ad] Endereço:a Department of Medical Physics , Vejle Hospital , Vejle , Denmark.
[Ti] Título:The potential benefits from respiratory gating for breast cancer patients regarding target coverage and dose to organs at risk when applying strict dose limits to the heart: results from the DBCG HYPO trial.
[So] Source:Acta Oncol;57(1):113-119, 2018 Jan.
[Is] ISSN:1651-226X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The potential benefits from respiratory gating (RG) compared to free-breathing (FB) regarding target coverage and dose to organs at risk for breast cancer patients receiving post-operative radiotherapy (RT) in the DBCG HYPO multicentre trial are reported. MATERIAL AND METHODS: Patients included in the DBCG HYPO trial were randomized between 50 Gy in 25 fractions (normofractionated) versus 40 Gy in 15 fractions (hypofractionated). A tangential forward field-in-field dose planning technique was used to cover the clinical target volume (CTV) with the intent to limit dose to the left anterior descending coronary artery (LADCA) to 20 Gy and 17 Gy in the normo- and hypofractionated arms, respectively. Treatment plan data for 1327 patients from four Danish centres was retrospectively analyzed. FB right-sided patients served as control group for the left-sided patients regarding CTV V (relative volume receiving at least 95% of the prescribed dose), mean heart dose (MHD) and mean lung dose (MLD). RESULTS: Median CTV V was for FB right-sided, FB left-sided and RG left-sided patients 94.6, 92.6 and 94.7% for normofractionated therapy, respectively, and 94.6, 91.8 and 94.4% for hypofractionated therapy and did not differ significantly for RG left-sided plans compared to FB right-sided in either study arm. CTV V was significantly lower for FB versus RG for left-sided plans in both arms. Median MHD was 0.7, 1.8 and 1.5 Gy (normofractionated therapy) versus 0.6, 1.5 and 1.2 Gy (hypofractionated therapy), respectively. The corresponding median MLD was 9.0, 8.3 and 7.3 Gy versus 7.3, 6.4 and 5.8 Gy, respectively. CONCLUSIONS: RG for left-sided breast cancer patients ensured similar CTV V as for FB right-sided patients. MLD was lower for RG due to the increased lung volume. MHD was generally low due to strict protocol-defined maximum dose to LADCA, but for left-sided patients RG led to significantly lower MHD.
[Mh] Termos MeSH primário: Órgãos em Risco
Dosagem Radioterapêutica
Planejamento da Radioterapia Assistida por Computador
Neoplasias da Mama Unilaterais/radioterapia
[Mh] Termos MeSH secundário: Adulto
Idoso
Idoso de 80 Anos ou mais
Suspensão da Respiração
Vasos Coronários/diagnóstico por imagem
Fracionamento de Dose
Feminino
Coração/diagnóstico por imagem
Seres Humanos
Meia-Idade
Tomografia Computadorizada por Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE; MULTICENTER STUDY; RANDOMIZED CONTROLLED TRIAL
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180201
[Lr] Data última revisão:
180201
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171206
[St] Status:MEDLINE
[do] DOI:10.1080/0284186X.2017.1406139


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[PMID]:28743616
[Au] Autor:van Haaren P; Claassen-Janssen F; van de Sande I; Boersma L; van der Sangen M; Hurkmans C
[Ad] Endereço:Department of Radiation Oncology, Catharina Hospital, Eindhoven, The Netherlands. Electronic address: paul.v.haaren@catharinaziekenhuis.nl.
[Ti] Título:Heart position variability during voluntary moderate deep inspiration breath-hold radiotherapy for breast cancer determined by repeat CBCT scans.
[So] Source:Phys Med;40:88-94, 2017 Aug.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:Voluntary moderate deep inspiration breath hold (vmDIBH) in left-sided breast cancer radiotherapy reduces cardiac dose. The aim of this study was to investigate heart position variability in vmDIBH using CBCT and to compare this variability with differences in heart position between vmDIBH and free breathing (FB). For 50 patients initial heart position with respect to the field edge (HP-FE) was measured on a vmDIBH planning CT scan. Breath-hold was monitored using an in-house developed vertical plastic stick. On pre-treatment CBCT scans, heart position variability with respect to the field edge (Δ ) was measured, reflecting heart position variability when using an offline correction protocol. After registering the CBCT scan to the planning CT, heart position variability with respect to the chest wall (Δ ) was measured, reflecting heart position variability when using an online correction protocol. As a control group, vmDIBH and FB computed tomography (CT) scans were acquired for 30 patients and registering both scans on the chest wall. For 34 out of 50 patients, the average HP-FE and HP-CW increased over the treatment course in comparison to the planning CT. Averaged over all patients and all treatment fractions, the Δ and the Δ was 0.8±4.2mm (range -9.4-+10.6mm) and 1.0±4.4mm (range -8.3-+10.4mm) respectively. The average gain in heart to chest wall distance was 11.8±4.6mm when using vmDIBH instead of FB. In conclusion, substantial variability in heart position using vmDIBH was observed during the treatment course.
[Mh] Termos MeSH primário: Neoplasias da Mama/radioterapia
Suspensão da Respiração
Coração/diagnóstico por imagem
Planejamento da Radioterapia Assistida por Computador
Tomografia Computadorizada por Raios X
[Mh] Termos MeSH secundário: Seres Humanos
Movimento
Radioterapia Adjuvante
Radioterapia de Intensidade Modulada
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180119
[Lr] Data última revisão:
180119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170727
[St] Status:MEDLINE


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[PMID]:28462867
[Au] Autor:Beilla S; Younes T; Vieillevigne L; Bardies M; Franceries X; Simon L
[Ad] Endereço:CRCT UMR 1037 INSERM/UPS, 2 avenue Hubert Curien, Toulouse 31037, France.
[Ti] Título:Monte Carlo dose calculation in presence of low-density media: Application to lung SBRT treated during DIBH.
[So] Source:Phys Med;41:46-52, 2017 Sep.
[Is] ISSN:1724-191X
[Cp] País de publicação:Italy
[La] Idioma:eng
[Ab] Resumo:PURPOSE: Commercial algorithms used in Radiotherapy include approximations that are generally acceptable. However their limits can be seen when confronted with small fields and low-density media. These conditions exist during the treatment of lung cancers with Stereotactic Body Radiation Therapy (SBRT) achieved with the "Deep Inspiration Breath Hold" (DIBH) technique. A Monte Carlo (MC) model of a linear accelerator was used to assess the performance of two algorithms (Varian Acuros and AAA) in these conditions. This model is validated using phantoms with different densities. Lastly, results for SBRT cases are compared to both Acuros and AAA. METHODS: A Varian TrueBeam linac was modeled using GATE/Geant4 and validated by comparing dose distributions for simple fields to measurements in water and in heterogeneous phantoms composed of PMMA and two types of cork (corresponding to lung densities during free-breathing and DIBH). Experimental measurements are also compared to AAA and Acuros. Finally, results of Acuros/AAA are compared to MC for a clinical case (SBRT during DIBH). RESULTS: Based on 1D gamma index comparisons with measurements in water, the TrueBeam model was validated (>97% of points passed this test). In heterogeneous phantoms, and in particular for small field sizes, very low density (0.12g.cm ) and at the edge of the field, MC model was still in good agreement with measurements whilst AAA and Acuros showed discrepancies. With the patient CT, similar differences between MC and AAA/Acuros were observed for static fields but disappeared using an SBRT arc field. CONCLUSIONS: Our MC model is validated and limits of commercial algorithms are shown in very low densities.
[Mh] Termos MeSH primário: Neoplasias Pulmonares/radioterapia
Radiocirurgia
Planejamento da Radioterapia Assistida por Computador
[Mh] Termos MeSH secundário: Algoritmos
Suspensão da Respiração
Seres Humanos
Modelos Teóricos
Método de Monte Carlo
Imagens de Fantasmas
Dosagem Radioterapêutica
[Pt] Tipo de publicação:JOURNAL ARTICLE; VALIDATION STUDIES
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180118
[Lr] Data última revisão:
180118
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


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[PMID]:27773445
[Au] Autor:Lens E; Gurney-Champion OJ; Tekelenburg DR; van Kesteren Z; Parkes MJ; van Tienhoven G; Nederveen AJ; van der Horst A; Bel A
[Ad] Endereço:Department of Radiation Oncology, Academic Medical Center/University of Amsterdam, The Netherlands. Electronic address: e.lens@amc.uva.nl.
[Ti] Título:Abdominal organ motion during inhalation and exhalation breath-holds: pancreatic motion at different lung volumes compared.
[So] Source:Radiother Oncol;121(2):268-275, 2016 11.
[Is] ISSN:1879-0887
[Cp] País de publicação:Ireland
[La] Idioma:eng
[Ab] Resumo:PURPOSE: Contrary to what is commonly assumed, organs continue to move during breath-holding. We investigated the influence of lung volume on motion magnitude during breath-holding and changes in velocity over the duration of breath-holding. MATERIALS AND METHODS: Sixteen healthy subjects performed 60-second inhalation breath-holds in room-air, with lung volumes of ∼100% and ∼70% of the inspiratory capacity, and exhalation breath-holds, with lung volumes of ∼30% and ∼0% of the inspiratory capacity. During breath-holding, we obtained dynamic single-slice magnetic-resonance images with a time-resolution of 0.6s. We used 2-dimensional image correlation to obtain the diaphragmatic and pancreatic velocity and displacement during breath-holding. RESULTS: Organ velocity was largest in the inferior-superior direction and was greatest during the first 10s of breath-holding, with diaphragm velocities of 0.41mm/s, 0.29mm/s, 0.16mm/s and 0.15mm/s during BH , BH , BH and BH , respectively. Organ motion magnitudes were larger during inhalation breath-holds (diaphragm moved 9.8 and 9.0mm during BH and BH , respectively) than during exhalation breath-holds (5.6 and 4.3mm during BH and BH , respectively). CONCLUSION: Using exhalation breath-holds rather than inhalation breath-holds and delaying irradiation until after the first 10s of breath-holding may be advantageous for irradiation of abdominal tumors.
[Mh] Termos MeSH primário: Suspensão da Respiração
Inalação/fisiologia
Pulmão/fisiologia
Movimento/fisiologia
Pâncreas/fisiologia
[Mh] Termos MeSH secundário: Adulto
Diafragma/diagnóstico por imagem
Diafragma/fisiologia
Expiração/fisiologia
Feminino
Seres Humanos
Pulmão/diagnóstico por imagem
Medidas de Volume Pulmonar/métodos
Imagem por Ressonância Magnética/métodos
Masculino
Pâncreas/diagnóstico por imagem
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180119
[Lr] Data última revisão:
180119
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


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[PMID]:29125799
[Au] Autor:Noren SR; Poll CP; Edwards MS
[Ti] Título:Body Growth and Rapid Hematological Development Support Breath Hold of Baby Belugas (Delphinapterus leucas) during Subice Transit.
[So] Source:Physiol Biochem Zool;91(1):691-704, 2018 Jan/Feb.
[Is] ISSN:1537-5293
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Body size and oxygen stores in the blood and muscle set breath-hold limits in marine mammals, yet these characteristics are understudied in immature cetaceans. We examined body mass and hematology from birth through adulthood in beluga whales (Delphinapterus leucas). At birth, body mass was 8% and 6% of the maximum mass recorded for adult females and males, respectively. Body mass then increased rapidly, approaching an asymptote around 12 yr for females and 18 yr for males. Interestingly, red blood cell counts, hemoglobin content, and hematocrit levels decreased after birth; this neonatal anemia was reversed as levels increased after 2 mo postpartum. Mature levels were obtained at approximately 8, 9, and 11 mo postpartum, respectively. Neonatal mean corpuscular hemoglobin also increased with ontogeny; mature levels were achieved by approximately 13 mo after birth. In contrast, mean corpuscular volume and mean corpuscular hemoglobin concentration demonstrated a significant but subtle increase throughout ontogeny. Our results indicate that postnatal maturation was required and that maturation occurred far earlier than the age at weaning (i.e., 2-3 yr postpartum). This is atypical of marine mammals, which generally achieve mature hemoglobin levels at weaning. Hematological maturation before maternal independence undoubtedly supports the prolonged breath holds of young belugas transiting under sea ice. This assessment enhances our knowledge of cetacean physiology and provides important inputs for determining age-specific dive capacity, yielding insights into age-specific flexibility to alter underwater behaviors, as will be required for future regime shifts and disturbances.
[Mh] Termos MeSH primário: Envelhecimento
Beluga/sangue
Beluga/crescimento & desenvolvimento
Suspensão da Respiração
Hemoglobinas/metabolismo
[Mh] Termos MeSH secundário: Animais
Comportamento Animal
Peso Corporal
Feminino
Camada de Gelo
Masculino
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Hemoglobins)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:171215
[Lr] Data última revisão:
171215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171111
[St] Status:MEDLINE
[do] DOI:10.1086/694920


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[PMID]:28816159
[Au] Autor:Chang JY; Zhang X; Knopf A; Li H; Mori S; Dong L; Lu HM; Liu W; Badiyan SN; Both S; Meijers A; Lin L; Flampouri S; Li Z; Umegaki K; Simone CB; Zhu XR
[Ad] Endereço:Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: jychang@mdanderson.org.
[Ti] Título:Consensus Guidelines for Implementing Pencil-Beam Scanning Proton Therapy for Thoracic Malignancies on Behalf of the PTCOG Thoracic and Lymphoma Subcommittee.
[So] Source:Int J Radiat Oncol Biol Phys;99(1):41-50, 2017 Sep 01.
[Is] ISSN:1879-355X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Pencil-beam scanning (PBS) proton therapy (PT), particularly intensity modulated PT, represents the latest advanced PT technology for treating cancers, including thoracic malignancies. On the basis of virtual clinical studies, PBS-PT appears to have great potential in its ability to tightly tailor the dose to the target while sparing critical structures, thereby reducing treatment-related toxicities, particularly for tumors in areas with complicated anatomy. However, implementing PBS-PT for moving targets has several additional technical challenges compared with intensity modulated photon radiation therapy or passive scattering PT. Four-dimensional computed tomography-based motion management and robust optimization and evaluation are crucial for minimizing uncertainties associated with beam range and organ motion. Rigorous quality assurance is required to validate dose delivery both before and during the course of treatment. Active motion management (eg, breath hold), beam gating, rescanning, tracking, or adaptive planning may be needed for cases involving significant motion or changes in motion or anatomy over the course of treatment.
[Mh] Termos MeSH primário: Movimento
Guias de Prática Clínica como Assunto
Terapia com Prótons/métodos
Radioterapia de Intensidade Modulada/métodos
Neoplasias Torácicas/radioterapia
[Mh] Termos MeSH secundário: Suspensão da Respiração
Esôfago
Tomografia Computadorizada Quadridimensional
Seres Humanos
Pulmão
Órgãos em Risco
Melhoria de Qualidade
Respiração
Treinamento por Simulação/métodos
Neoplasias Torácicas/diagnóstico por imagem
Neoplasias Torácicas/patologia
Carga Tumoral
Incerteza
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170821
[Lr] Data última revisão:
170821
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170818
[St] Status:MEDLINE


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[PMID]:28708735
[Au] Autor:Wong OL; Goh Lo G; Yuan J; Chung WK; Ho WHB; Noseworthy MD
[Ad] Endereço:From the *Department of Medical Physics and Applied Radiation Science, McMaster University; †Imagins Research Center, St. Joseph's Healthcare, Hamilton, Ontario, Canada; ‡Medical Physics and Research Department, and §Interventional and Radiology Department, Hong Kong Sanatorium & Hospital, Hong Kong Special Administrative Region (SAR), China; ∥School of Biomedical Engineering, and ¶Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada.
[Ti] Título:Evaluation and Minimization of the Pseudohepatic Anisotropy Artifact in Liver Intravoxel Incoherent Motion.
[So] Source:J Comput Assist Tomogr;41(5):679-687, 2017 Sep/Oct.
[Is] ISSN:1532-3145
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: The aim of this study was to evaluate the effect of the pseudohepatic anisotropy artifact on liver intravoxel incoherent motion (IVIM) metrics and whether the use of multiple gradient directions in the IVIM acquisition minimizes the artifact. MATERIALS AND METHODS: Multiple breath-holding and forced shallow free-breathing IVIM scans were performed on 8 healthy volunteers using 1 and 6 gradient directions. Cluster analysis was carried out to separate motion-contaminated parenchyma from liver parenchyma and vessels. Nonlinear motion analysis was also performed to look for a possible link between IVIM metrics and nonlinear liver motion. RESULTS: On the basis of the resulted clusters, motion-contaminated parenchyma is often noted in the left liver lobe, where the prominent pseudohepatic artifact has previously been identified. A significant reduction in outliers was obtained with the acquisition of 6 noncoplanar gradient directions and when using forced shallow free-breathing. CONCLUSION: The pseudohepatic anisotropy artifact can be minimized when using multiple diffusion-encoding gradient directions and forced free-breathing during IVIM acquisition.
[Mh] Termos MeSH primário: Artefatos
Processamento de Imagem Assistida por Computador/métodos
Fígado/anatomia & histologia
Imagem por Ressonância Magnética/métodos
[Mh] Termos MeSH secundário: Adulto
Anisotropia
Suspensão da Respiração
Análise por Conglomerados
Feminino
Seres Humanos
Masculino
Movimento (Física)
Valores de Referência
Reprodutibilidade dos Testes
Respiração
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171003
[Lr] Data última revisão:
171003
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170715
[St] Status:MEDLINE
[do] DOI:10.1097/RCT.0000000000000604



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