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Song B, Wang Y, Zhao X, Liu L, Wang C, Wang A, Du W, Wang Y. Association between statin use and short-term outcome based on severity of ischemic stroke: a cohort study. PLoS One 2014; 9:e84389. [PMID: 24465409 PMCID: PMC3897364 DOI: 10.1371/journal.pone.0084389] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 11/14/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Statins reportedly improve clinical outcomes for ischemic stroke patients. However, it is unclear whether the contribution of statin treatment varies depending on the severity of stroke. We sought to investigate the relationship between statin use and the outcome of acute first-ever ischemic stroke patients stratified by stroke severity. METHODS A total of 7,455 acute first-ever ischemic stroke patients without statin treatment before onset were eligible from the China National Stroke Registry. A National Institutes of Health Stroke Scale (NIHSS) score of 0 to 4 was defined as minor stroke, and a NIHSS score of >4 was defined as non-minor stroke. We analyzed the association between statin use during hospitalization and mortality as well as functional outcome (measured by a modified Rankin Scale score of 0-5) at 3 months after onset using multivariable logistic regression models. RESULTS A total of 3,231 (43.3%) patients received statin treatment during hospitalization. Multivariable analysis showed that statin use during hospitalization decreased mortality of ischemic stroke patients (OR, 0.51; 95%CI, 0.38-0.67), but did not improve poor functional outcomes (OR, 0.95; 95CI%, 0.81-1.11) at 3 months. The interaction between statin use and stroke severity was significant both in dependence and death outcome (P = 0.04 for dependence outcome, P = 0.03 for death outcome). After stratification by stroke severity, statin use during hospitalization decreased the mortality of stroke (OR, 0.44; 95%CI, 0.31-0.62) and poor functional outcome (OR, 0.73; 95%CI, 0.57-0.92) at 3 months in the non-minor stroke group. CONCLUSIONS Statin use during hospitalization may improve the clinical outcome of acute first-ever ischemic stroke depending on the severity of stroke. Non-minor stroke patients may obtain benefit from statin treatment with improvements in poor functional outcomes and mortality.
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Looi CY, Sasahara Y, Watanabe Y, Satoh M, Hakozaki I, Uchiyama M, Wong WF, Du W, Uchiyama T, Kumaki S, Tsuchiya S, Kure S. The open conformation of WASP regulates its nuclear localization and gene transcription in myeloid cells. Int Immunol 2014; 26:341-52. [DOI: 10.1093/intimm/dxt072] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Zou YM, Tan JP, Li N, Yang JS, Yu BC, Yu JM, Du W, Zhang WJ, Cui LQ, Wang QS, Xia XN, Li JJ, Zhou PY, Zhang BH, Liu ZY, Zhang SG, Sun LY, Liu N, Deng RX, Ma LH, Chen WJ, Zhang YQ, Liu J, Zhang SM, Lan XY, Zhao YM, Wang LN. The prevalence of Parkinson's disease continues to rise after 80 years of age: a cross-sectional study of Chinese veterans. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2014; 18:3908-3915. [PMID: 25555883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE The purpose of this study was to examine whether the prevalence of Parkinson's disease (PD) continues to rise after 80 years of age. METHODS This is a two-stage, multi-center, cross-sectional study using a stratified cluster sampling approach was employed. Subjects included veterans at ≥ 60 years of age living in veterans' communities for at least one month in 18 major cities across China. In the first step, possible PD was screened using a PD screening scale. Demographic and relevant information were collected. In the second step, PD diagnosis was established using the United Kingdom Parkinson's Disease Society Brain Bank (UKPDSBB) diagnostic criteria. RESULTS The study was conducted during the period from December 2009 to December 2012. The study included 277 veterans' communities. Among the approached 11,593 subjects, 9676 subjects, (9096 men, 580 women) responded. The response rate was 83.46%.The age was ≥ 80 years in 6722 (69.47%) subjects. A diagnosis of PD was established in 228 subjects (2.36%) in the entire sample. The rate of PD was 2.65% in those with an age of ≥ 80 years. The rate of PD increased with increasing age (0%, 1.84%, 2.60% and 3.68% in the subjects at < 70, 70-79, 80-89 and ≥ 90 years of age, respectively; χ2 = 10.891, p = 0.001 in chi-square test). The rate of PD was higher in men (2.44%) than in women (1.46%) on the surface. However, no significant difference was detected (p = 0.241). CONCLUSIONS The prevalence of PD continues to increase beyond the age of 80 years. The prevalence of PD in Chinese veterans is not lower than that in other countries and regions.
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Zhao L, Du W, Zhao X, Liu L, Wang C, Wang Y, Wang A, Liu G, Wang Y, Xu Y. Favorable functional recovery in overweight ischemic stroke survivors: findings from the China National Stroke Registry. J Stroke Cerebrovasc Dis 2013; 23:e201-6. [PMID: 24231138 DOI: 10.1016/j.jstrokecerebrovasdis.2013.10.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 10/06/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Obesity paradox has been reported because of the inverse relationship between the body mass index (BMI) and mortality in stroke patients. The relationship between BMI and functional recovery in stroke survivors is less well established. We explored the impact of BMI on functional recovery and mortality in stroke patients in the China National Stroke Registry (CNSR). METHODS Patients were consecutively recruited based on a standard protocol and prospectively followed up for outcomes at 3 months after disease onset. Patients were divided into 5 groups according to their BMI: underweight (<18.5 kg/m(2)), normal weight (18.5-22.9 kg/m(2)), overweight (23-27.4 kg/m(2)), obese (27.5-32.4 kg/m(2)), or severely obese (≥32.5 kg/m(2)). Multivariate logistic regression was performed to analyze the association between BMI and functional recovery or mortality. RESULTS CNSR enrolled 22,216 patients hospitalized for acute cerebrovascular events, and 10,905 eligible acute ischemic stroke patients were analyzed in our study. Favorable functional recovery (modified Rankin Scale score 0-1) was seen in 52.4% of underweight, 55.0% of normal weight, 61.0% of overweight, 59.2% of obese, and 60.3% of severely obese stroke survivors (P < .001). Overweight was independently associated with favorable 3-month functional recovery (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.12-1.38). Mortality rate was 14.9% in underweight, 7.8% in normal weight, 7.1% in overweight, 7.2% in obese, and 11.5% in severely obese patients (P < .001). Severe obesity was independently associated with higher 3-month mortality (OR 2.01; 95% CI 1.10-3.69). CONCLUSIONS The stroke obesity paradox can be extended to include functional recovery but should not be interpreted as the fatter the better.
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Takabe R, Baba M, Nakamura K, Du W, Khan MA, Koike S, Toko K, Hara KO, Usami N, Suemasu T. Fabrication and characterizations of phosphorus-doped n-type BaSi2epitaxial films grown by molecular beam epitaxy. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pssc.201300326] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Harris K, Du W, Cowley C, Forbes T, Kim D. A Prospective Multicenter Study of Balloon Angioplasty for the Treatment of Native and Recurrent Coarctation of the Aorta. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Guo F, Li J, Zhang S, Du W, Amarachintha S, Sipple J, Phelan J, Grimes HL, Zheng Y, Pang Q. mTOR kinase inhibitor sensitizes T-cell lymphoblastic leukemia for chemotherapy-induced DNA damage via suppressing FANCD2 expression. Leukemia 2013; 28:203-6. [PMID: 23852546 DOI: 10.1038/leu.2013.215] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Du W, Casey K, Kudchadker R. SU-E-T-134: Automated Analysis of Leaf Position Accuracy for Multi-Leaf Collimator Quality Assurance. Med Phys 2013. [DOI: 10.1118/1.4814569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Cummins HZ, Li G, Du W, Hwang YH, Shen GQ. Light Scattering Spectroscopy of Orthoterphenyl: Idealized and Extended Mode Coupling Analysis. ACTA ACUST UNITED AC 2013. [DOI: 10.1143/ptp.126.21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Du W, Feng D, Xu J, Wei W. Computational Fluid Dynamics Modeling of Gas-Liquid Two-Phase Flow around a Spherical Particle. Chem Eng Technol 2013. [DOI: 10.1002/ceat.201200486] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Guo F, Li J, Du W, Zhang S, O'Connor M, Thomas G, Kozma S, Zingarelli B, Pang Q, Zheng Y. mTOR regulates DNA damage response through NF-κB-mediated FANCD2 pathway in hematopoietic cells. Leukemia 2013; 27:2040-2046. [PMID: 23538752 DOI: 10.1038/leu.2013.93] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 02/14/2013] [Accepted: 03/20/2013] [Indexed: 12/16/2022]
Abstract
Hematopoietic stem/progenitor cells (HSPCs) function to give rise to mature blood cells. Effective DNA damage response (DDR) and maintenance of genomic stability are crucial for normal functioning of HSPCs. Mammalian target of rapamycin (mTOR) integrates signals from nutrients and growth factors to control protein synthesis, cell growth, survival and metabolism, and has been shown to regulate DDR in yeast and human cancer cells through the p53/p21 signaling cascade. Here, we show that gene targeting of mTOR in HSPCs causes a defective DDR due to a variety of DNA damage agents, mimicking that caused by deficient FANCD2, a key component of the Fanconi anemia (FA) DDR machinery. Mechanistically, mTOR(-/-) HSPCs express drastically reduced FANCD2. Consistent with these genetic findings, inactivation of mTOR in human lymphoblast cells by pp242 or Torin 1, mTOR kinase inhibitors, suppresses FANCD2 expression and causes a defective DDR that can be rescued by reconstitution of exogenous FANCD2. Further mechanistic studies show that mTOR deficiency or inactivation increases phosphorylation and nuclear translocation of nuclear factor (NF)-κB, which results in an enhanced NF-κB binding to FANCD2 promoter to suppress FANCD2 expression. Thus, mTOR regulates DDR and genomic stability in hematopoietic cells through a noncanonical pathway involving NF-κB-mediated FANCD2 expression.
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Lin T, Li N, Du W, Song X, Zheng X. Road traffic disability in China: prevalence and socio-demographic disparities. J Public Health (Oxf) 2013; 35:541-7. [DOI: 10.1093/pubmed/fdt003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Yao CJ, Du W, Zhang Q, Zhang F, Zeng F, Chen FP. Fanconi anemia pathway--the way of DNA interstrand cross-link repair. DIE PHARMAZIE 2013; 68:5-11. [PMID: 23444773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The study of rare genetic diseases usually inspires the research of cancer biology. Fanconi anemia (FA), is a rare cancer susceptibility syndrome with an incidence of only 1 per 350,000 births. FA is an autosomal recessive disease with three main features: chromosome instability, hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC), cisplatin and so on, and susceptible to a number of cancer types, mainly leukemia and squamous cell carcinomas of the head and neck or gynecologic system. DNA crosslinking agents may led to DNA cross-linking lesion, and Fanconi anemia pathway plays a key role in repairing its cross-linking. However, FA pathway is closely linked with carcinogenesis and tumor drug resistance. This paper mainly focuses on the FA pathway and its progress in cancer research.
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He X, Ruan J, Du W, Chen G, Zuo X, Cao Y. PRM1 variant RS35576928 (R34S) was associated with defect spermatogenesis in the Chinese han population. Fertil Steril 2012. [DOI: 10.1016/j.fertnstert.2012.07.535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Jin HR, Zhao J, Zhang Z, Liao Y, Wang CZ, Huang WH, Li SP, He TC, Yuan CS, Du W. The antitumor natural compound falcarindiol promotes cancer cell death by inducing endoplasmic reticulum stress. Cell Death Dis 2012; 3:e376. [PMID: 22914324 PMCID: PMC3434669 DOI: 10.1038/cddis.2012.122] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Falcarindiol (FAD) is a natural polyyne with various beneficial biological activities. We show here that FAD preferentially kills colon cancer cells but not normal colon epithelial cells. Furthermore, FAD inhibits tumor growth in a xenograft tumor model and exhibits strong synergistic killing of cancer cells with 5-fluorouracil, an approved cancer chemotherapeutic drug. We demonstrate that FAD-induced cell death is mediated by induction of endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). Decreasing the level of ER stress, either by overexpressing the ER chaperone protein glucose-regulated protein 78 (GRP78) or by knockout of components of the UPR pathway, reduces FAD-induced apoptosis. In contrast, increasing the level of ER stress by knocking down GRP78 potentiates FAD-induced apoptosis. Finally, FAD-induced ER stress and apoptosis is correlated with the accumulation of ubiquitinated proteins, suggesting that FAD functions at least in part by interfering with proteasome function, leading to the accumulation of unfolded protein and induction of ER stress. Consistent with this, inhibition of protein synthesis by cycloheximide significantly decreases the accumulation of ubiquitinated proteins and blocks FAD-induced ER stress and cell death. Taken together, our study shows that FAD is a potential new anticancer agent that exerts its activity through inducing ER stress and apoptosis.
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Du W, Wang S, Zhou Q, Li X, Chu J, Chang Z, Tao Q, Ng EKO, Fang J, Sung JJY, Yu J. ADAMTS9 is a functional tumor suppressor through inhibiting AKT/mTOR pathway and associated with poor survival in gastric cancer. Oncogene 2012; 32:3319-28. [PMID: 22907434 DOI: 10.1038/onc.2012.359] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 06/27/2012] [Accepted: 06/30/2012] [Indexed: 12/15/2022]
Abstract
Using genome-wide promoter methylation analysis, we identified a disintegrin-like and metalloprotease with thrombospondin type 1 motif 9 (ADAMTS9) is methylated in cancer. We aim to clarify its epigenetic inactivation, biological function and clinical implication in gastric cancer. ADAMTS9 was silenced in 6 out of 8 gastric cancer cell lines. The loss of ADAMTS9 expression was regulated by promoter hypermethylation and could be restored by demethylation agent. Ectopic expression of ADAMTS9 in gastric cancer cell lines (AGS, BGC823) inhibited cell growth curve in both the cell lines (P<0.0001), suppressed colony formation (P<0.01) and induced apoptosis (P<0.001 in AGS, P<0.01 in BGC823). Moreover, conditioned culture medium from ADAMTS9-transfected cell lines significantly disrupted the human umbilical vein endothelial cell tube formation capacity on Matrigel (P<0.01 in AGS, P<0.001 in BGC823). The in vivo growth of ADAMTS9 cells in nude mice was also markedly diminished after stable expression of ADAMTS9 (P<0.001). On the other hand, ADAMTS9 knockdown promoted cell proliferation (P<0.001). We further revealed that ADAMTS9 inhibited tumor growth by blocking activation of Akt and its downstream target the mammalian target of rapamycin (mTOR). ADAMTS9 also reduced phosphorylation of mTOR downstream targets p70 ribosomal S6 kinase, eIF4E-binding protein and downregulated hypoxia-inducible factor-1α. Therefore, this is the first demonstration that ADAMTS9 is a critical tumor suppressor of gastric cancer progression at least in part through suppression of oncogenic AKT/mTOR signaling. Moreover, promoter methylation of ADAMTS9 was detected in 29.2% (21/72) of primary gastric tumors. Multivariate analysis showed that patients with ADAMTS9 methylation had a poorer overall survival (relative risk (RR)=2.788; 95% confidence interval, 1.474-5.274; P=0.002). Kaplan-Meier survival curves showed that ADAMTS9 methylation was significantly associated with shortened survival in gastric cancer patients (P=0.001, log-rank test). In conclusion, ADAMTS9 acts as a functional tumor suppressor in gastric cancer through inhibiting oncogenic AKT/mTOR signaling pathway. Methylation of ADAMTS9 is an independent prognostic factor of gastric cancer.
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Dong S, Hu Y, Du W, Tao W, Zhang X, Zhuang P, Li Y. Changes in Spontaneous Dorsal Horn Potentials after Dorsal Root Entry Zone Lesioning in Patients with Pain after Brachial Plexus Avulsion. J Int Med Res 2012; 40:1499-506. [PMID: 22971502 DOI: 10.1177/147323001204000429] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES: This study investigated spontaneous dorsal horn potentials in patients with pain after brachial plexus avulsion and determined the effect of dorsal root entry zone (DREZ) lesioning on these potentials and on pain levels. METHODS: Electrospinography (ESG) recordings were undertaken in seven patients using a noninvasive electrocorticography strip electrode. Measurements were taken from the DREZ on the intact side of the spinal cord before lesioning of the injured DREZ and from the injured DREZ before and after lesioning. RESULTS: DREZ lesioning had a significant positive effect on pain at 12 months postoperatively. At 15.0 Hz, the mean ESG power from the injured DREZ before lesioning was significantly higher than that from the intact DREZ. In addition, the mean ESG power from the injured DREZ after successful DREZ lesioning was significantly lower than that from the intact DREZ and that from the injured DREZ before lesioning. CONCLUSIONS: The ESG power from the injured DREZ increases in patients with pain after brachial plexus avulsion compared with that of the intact DREZ; this increase is reduced by successful DREZ lesioning.
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Gao S, Du W, Balter P. SU-C-213CD-04: Evaluation of IsoCal Imaging Isocenter Calibration System for Varian OBI Machines. Med Phys 2012. [DOI: 10.1118/1.4734633] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wang X, Zhao Z, Du W, Li X, Yang J. SU-E-J-49: Reliability Study of ExacTrac- System Image Isocenter Using an On-Demand QA Procedure. Med Phys 2012; 39:3663. [DOI: 10.1118/1.4734884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Anand A, Du W, Chung H, Frank S, Pugh T, Kudchadker R. SU-E-T-46: M.D. Anderson Prostate Seed Implant Dose Calculator. Med Phys 2012. [DOI: 10.1118/1.4735102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Du W, Yue Y, Tian X. Variation of isoflavones production in red clover as related to environment, growth stage and year. ACTA ALIMENTARIA 2012. [DOI: 10.1556/aalim.41.2012.2.8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Du W, Gao S, Wang X, Kudchadker R. SU-E-T-88: Evaluating Gantry Sag on Linear Accelerators and Introducing an MLC-Based Compensation Strategy. Med Phys 2012; 39:3722-3723. [PMID: 28517157 DOI: 10.1118/1.4735145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Gantry sag is one of the well-known sources of mechanical imperfections that compromise the spatial accuracy of radiation dose delivery. This study aims to quantify the gantry sag on multiple linacs and to investigate a multiple leaf collimator (MLC)-base strategy to compensate for gantry sag. METHODS We used the Winston-Lutz method to measure the gantry sag on three Varian linacs. A ball-bearing phantom was imaged with a square radiation field during gantry rotation. The images were analyzed to derive the radiation isocenter and subsequently the gantry sag, that is, the superior-inferior wobble of the radiation field center from the radiation isocenter as a function of gantry angle. Compensation for gantry sag was attempted by offsetting the MLC leaves at 90-degree collimator angle. The amount of offset was the opposite of measured gantry sag, which was gantry angle-specific. RESULTS Gantry sag was reproducible within a six-month period. On the three linacs, the maximum gantry sag was found to vary from 0.7 mm to 1.0 mm, depending on the linac and the collimator angle. The radiation field center moved inferiorly, or away from the gantry, when the gantry was rotated from 0 to 180 degrees. Comparison of gantry sag at 0- and 90-degree collimator angles showed that the uncertainty in MLC leaf positions did not increase the gantry sag. Instead, gantry sag was caused primarily by nonideal gantry rotation. After the MLC compensation was applied, the maximum gantry sag was reduced to less than 0.2 mm. CONCLUSIONS The results indicated that gantry sag on a linac can be quantitatively measured with sub-millimeter precision, using a simple ball-bearing phantom and the electronic portal imaging device. Reduction of gantry sag is feasible by applying a gantry angle-specific correction to MLC leaf positions at 90 degree collimator angle.
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Anand A, Kerns J, Du W, Kudchadker R. SU-E-T-69: A Novel Method Using Agfa-Kodak- Computer Radiography System for Routine Quality Assurance Tests on Linear Accelerators. Med Phys 2012. [DOI: 10.1118/1.4735125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Yang M, Du W, Frank S, Pugh T, Bruno T, Kudchadker R. SU-E-T-260: Radiation Exposure Estimation for 131Cs Prostate Implant Patient Release Determination. Med Phys 2012; 39:3763. [PMID: 28517343 DOI: 10.1118/1.4735327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Due to the short half-life and high energy of Cesium-131 (131Cs), the exposure rate outside the patient could potentially increase radiation exposure to hospital staff and exceed the maximum patient release exposure rate limit. A calculation technique has been developed to estimate the exposure rate at 1 meter from the patient, for prostate patients receiving 131Cs implants. METHODS In our calculation for each patient, all 131Cs sources were treated as one single source, and the point on the prostate with the shortest distance to skin surface was selected as the effective source position. Attenuation inside the patient was calculated based on the attenuation coefficient of 30 keV photons in water, assuming homogeneous patient density. This calculation technique was evaluated on our first 25 131Cs implant patients. For comparison, the exposure rate at approximately 1 meter inferior to patient perineum was measured prior to patient release using the Inovision 451P-RYR survey meter. RESULTS The distance from the edge of the prostate to skin surface along the inferior direction was the shortest in all 25 patients. The mean of the calculated exposure rates at 1 meter from skin surface was 0.53 mR/hr, 0.53 mR/hr, 0.04 mR/hr, 0.04 mR/hr and 1.5 mR/hr along the anterior, posterior, left, right and inferior directions, respectively. The mean of the measured exposure rate at 1 meter inferior to patient perineum was 1.1 mR/hr. The mean ratio of the measured versus calculated exposure rate was 0.74 (standard deviation = 0.23). CONCLUSIONS Our calculation technique is useful in determining in advance whether a patient may require hospitalization after his implant. The exposure rate at 1 meter inferior to patient perineum is a good indicator for determining whether the exposure rate along any direction might exceed the maximum allowed patient release exposure rate of 6 mR/hr.
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