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1.
Radiat Oncol ; 11: 66, 2016 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-27142674

RESUMO

BACKGROUND: To establish the feasibility of the dosimetric compliance criteria of the RTOG 1308 trial through testing against Intensity Modulation Radiation Therapy (IMRT) and Passive Scattering Proton Therapy (PSPT) plans. METHODS: Twenty-six lung IMRT and 26 proton PSPT plans were included in the study. Dose Volume Histograms (DVHs) for targets and normal structures were analyzed. The quality of IMRT plans was assessed using a knowledge-based engineering tool. RESULTS: Most of the RTOG 1308 dosimetric criteria were achieved. The deviation unacceptable rates were less than 10 % for most criteria; however, a deviation unacceptable rate of more than 20 % was computed for the planning target volume minimum dose compliance criterion. Dose parameters for the target volume were very close for the IMRT and PSPT plans. However, the PSPT plans led to lower dose values for normal structures. The dose parameters in which PSPT plans resulted in lower values than IMRT plans were: lung V5Gy (%) (34.4 in PSPT and 47.2 in IMRT); maximum spinal cord dose (31.7 Gy in PSPT and 43.5 Gy in IMRT); heart V5Gy (%) (19 in PSPT and 47 in IMRT); heart V30Gy (%) (11 in PSPT and 19 in IMRT); heart V45Gy (%) (7.8 in PSPT and 12.1 in IMRT); heart V50% (Gy) (7.1 in PSPT and 9.8 in IMRT) and mean heart dose (7.7 Gy in PSPT and 14.9 Gy in IMRT). CONCLUSIONS: The revised RTOG 1308 dosimetric compliance criteria are feasible and achievable.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Quimiorradioterapia/métodos , Neoplasias Pulmonares/radioterapia , Fótons , Radiometria/métodos , Radioterapia de Intensidade Modulada/métodos , Estudos de Viabilidade , Humanos , Terapia com Prótons/métodos , Garantia da Qualidade dos Cuidados de Saúde , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
2.
Front Oncol ; 6: 47, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26973814

RESUMO

Radiotherapy clinical-trial quality assurance is a crucial yet challenging process. This note presents a tool that automatically extracts dose/volume statistics for determining dosimetry compliance review with improved efficiency and accuracy. A major objective of this study is to develop an automated solution for clinical-trial radiotherapy dosimetry review.

3.
J Appl Clin Med Phys ; 17(1): 4-11, 2016 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-26894343

RESUMO

Our previous study demonstrated the application of the Dempster-Shafer theory of evidence to dose/volume/outcome data analysis. Specifically, it provided Yager's rule to fuse data from different institutions pertaining to radiotherapy pneumonitis versus mean lung dose. The present work is a follow-on study that employs the optimal unified combination rule, which optimizes data similarity among independent sources. Specifically, we construct belief and plausibility functions on the lung cancer radiotherapy dose outcome datasets, and then apply the optimal unified combination rule to obtain combined belief and plausibility, which bound the probabilities of pneumonitis incidence. To estimate the incidence of pneumonitis at any value of mean lung dose, we use the Lyman-Kutcher-Burman (LKB) model to fit the combined belief and plausibility curves. The results show that the optimal unified combination rule yields a narrower uncertainty range (as represented by the belief-plausibility range) than Yager's rule, which is also theoretically proven.


Assuntos
Neoplasias Pulmonares/radioterapia , Modelos Teóricos , Humanos , Dosagem Radioterapêutica
4.
Oncotarget ; 6(35): 38327-35, 2015 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-26413811

RESUMO

The risk of local recurrence (LR), distant metastases (DM) and overall survival (OS) of locally advanced rectal cancer after preoperative chemoradiation can be estimated by prediction models and visualized using nomograms, which have been trained and validated in European clinical trial populations. Data of 277 consecutive locally advanced rectal adenocarcinoma patients treated with preoperative chemoradiation and surgery from Shanghai Cancer Center, were retrospectively collected and used for external validation. Concordance index (C-index) and calibration curves were used to assess the performance of the previously developed prediction models in this routine clinical validation population. The C-index for the published prediction models was 0.72 ± 0.079, 0.75 ± 0.043 and 0.72 ± 0.089 in predicting 2-year LR, DM and OS in the Chinese population, respectively. Kaplan-Meier curves indicated good discriminating performance regarding LR, but could not convincingly discriminate a low-risk and medium-risk group for distant control and OS. Calibration curves showed a trend of underestimation of local and distant control, as well as OS in the observed data compared with the estimates predicted by the model. In conclusion, we externally validated three models for predicting 2-year LR, DM and OS of locally advanced rectal cancer patients who underwent preoperative chemoradiation and curative surgery with good discrimination in a single Chinese cohort. However, the model overestimated the local control rate compared to observations in the clinical cohort. Validation in other clinical cohorts and optimization of the prediction model, perhaps by including additional prognostic factors, may enhance model validity and its applicability for personalized treatment of locally advanced rectal cancer.


Assuntos
Adenocarcinoma/diagnóstico , Adenocarcinoma/terapia , Técnicas de Apoio para a Decisão , Neoplasias Retais/diagnóstico , Neoplasias Retais/terapia , Adenocarcinoma/etnologia , Adenocarcinoma/mortalidade , Adenocarcinoma/secundário , Idoso , Povo Asiático , Quimiorradioterapia Adjuvante , China , Análise Discriminante , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Recidiva Local de Neoplasia , Nomogramas , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Neoplasias Retais/etnologia , Neoplasias Retais/mortalidade , Neoplasias Retais/patologia , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
5.
Proc Natl Acad Sci U S A ; 109(16): 6088-93, 2012 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-22492931

RESUMO

Crystalline biominerals do not resemble faceted crystals. Current explanations for this property involve formation via amorphous phases. Using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), here we examine forming spicules in embryos of Strongylocentrotus purpuratus sea urchins, and observe a sequence of three mineral phases: hydrated amorphous calcium carbonate (ACC · H(2)O) → dehydrated amorphous calcium carbonate (ACC) → calcite. Unexpectedly, we find ACC · H(2)O-rich nanoparticles that persist after the surrounding mineral has dehydrated and crystallized. Protein matrix components occluded within the mineral must inhibit ACC · H(2)O dehydration. We devised an in vitro, also using XANES-PEEM, assay to identify spicule proteins that may play a role in stabilizing various mineral phases, and found that the most abundant occluded matrix protein in the sea urchin spicules, SM50, stabilizes ACC · H(2)O in vitro.


Assuntos
Materiais Biocompatíveis/química , Calcificação Fisiológica , Carbonato de Cálcio/química , Transição de Fase , Animais , Materiais Biocompatíveis/metabolismo , Carbonato de Cálcio/metabolismo , Cristalização , Embrião não Mamífero/química , Embrião não Mamífero/metabolismo , Embrião não Mamífero/ultraestrutura , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Microscopia Eletrônica/métodos , Minerais/química , Minerais/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Strongylocentrotus purpuratus/química , Strongylocentrotus purpuratus/embriologia , Strongylocentrotus purpuratus/metabolismo , Água/química , Espectroscopia por Absorção de Raios X/métodos
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