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find Keyword "误差" 19 results
  • Comparative Study on Calculation Methods of Seasonal Index for Outpatient Volume in a Hospital

    目的:在移动平均趋势剔除法、最小二乘法两种趋势剔除法中找出一种能较好反映某医院门诊量季节变化规律的方法。方法:根据该医院2005~2008年各月门诊数据,运用移动平均趋势剔除法、最小二乘法分别计算该医院门诊患者的季节指数(seasonal index)和各月预测值,并对预测结果进行平均绝对偏差(MAD)、平均平方误差(MSE)、平均预测误差(AFE)、平均绝对百分误差(MAPE)分析。同时,判断实际值与预测值的容许区间的关系。结果:移动平均趋势剔除法和最小二乘法预测值的MAD、MSE、AFE、MAPE分别为766.94,888236.8542,-0.23,5.478249.8%和739.0196,802281.2,0.125,5.259-453%。移动平均趋势剔除法有4个实际值落在容许区间之外,最小二乘法有2个。结论:最小二乘法能够更好反映出该院门诊量季节变化的规律,是预测的最佳选择方案。

    Release date:2016-09-08 10:01 Export PDF Favorites Scan
  • Magnitude image-guided phase unwrapping algorithm of susceptibility weighted images

    To better use the phase information to compensate the influence of blood flow, the phase unwrapping problem in susceptibility weighted imaging (SWI) is studied in this paper. In order to improve the accuracy of unwrapping, this paper proposes a magnitude image-guided phase unwrapping algorithm of SWI. The basic idea is as follows: (1) reduce the influence of noise by improving the rotational invariant non-local principal component analysis method (PRI-NL-PCA); (2) extract the corresponding solid region in the phase image to avoid the influence of the background noise on the phase unwrapping method; (3) use the phase compensation method to constrain the phase image reconstructed by the K-space. Finally, the reliability of the unwrapping method is evaluated by using four kinds of statistics as quantification index: the number, mean (M), variance (Var), and positive percentage (Pos) and negative percentage (Neg) of phasic error points. By comparing the simulated data with 226 sets of true head SWI data, the results show that the proposed algorithm has high accuracy compared with the classical branch cut method and the least squares method.

    Release date:2017-10-23 02:15 Export PDF Favorites Scan
  • 摆位系统误差对乳腺癌调强放射治疗剂量分布的影响

    目的探究摆位系统误差对乳腺癌患者实施调强放射治疗的剂量学影响。 方法2012年10月对一典型乳腺癌改良根治术后患者分别设计常规三维适形切线野(CRT)、多野静态调强(s-IMRT)、旋转调强(VMAT)3种不同治疗技术的计划,在计划中将治疗中心点向患者左、右、腹、背、头、脚方向分别平移3、6 mm模拟2种不同程度的系统误差,共计39个计划与原计划进行比较,观察不同治疗技术间、不同平移距离,不同方向上的靶区及主要危及器官患侧肺和心脏的剂量变化。 结果对于3 mm摆位系统误差,靶区D95%于向背侧s-IMRT降低4.0%,VMAT降低3.5%,向右(患侧)s-IMRT降低3.0%,VMAT降低2.8%,其余均方向降低且<1.6%。对于主要危及器官,系统误差对s-IMRT技术的患侧肺接受20 Gy剂量的体积影响大,对VMAT技术的患侧肺接受10 Gy剂量的体积影响大。除此外,对主要危及器官患侧肺及其他剂量参数影响均小(3 mm<3%,6 mm<6%)。系统误差对3D-CRT技术的影响小(3 mm<3%,6 mm<6%)。6 mm的系统误差对靶区及危及器官的影响与3 mm趋势一致,仅变化程度更大,两种调强技术的靶区D95%降低>5%。 结论对乳腺癌改良根治术后的呈弧段状、位于胸廓表面的放射治疗靶区,s-IMRT和VMAT方式的调强治疗技术对治疗摆位系统误差的影响程度相当,但较CRT技术更敏感,其中以向患者背侧、健侧方向偏移影响最大。改良根治术后乳腺癌调强治疗的实施需要有较三维治疗更高的位置精度保证。

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  • A Comparative Study on the Results of Liver Function between Olympus AU1000 and Backman CX7 Detection Systems

    Objective To study the comparability of liver function results between the two detection systems. Methods Based on the NCCLS EP9-A document, 8 fresh serum samples were collected daily for the assay of 10 routine liver function parameters by utilizing the Olympus AU1000 and Backman CX7 detection systems respectively. The results were recorded over 5 days consecutively. Linearity equation and relative deviations were calculated. The comparability between the results obtained from different detection systems was evaluated according to the systematic error at medical decision level of CLIA, 88. Results The paired t-test showed that the results of the fresh serum samples had no significant difference between the two detection systems (Pgt;0.05). Except that the systematic error of albumin at low medical decision level exceeded the allowable error, all the other systematic errors at medical decision level were acceptable. Conclusion The results of liver function are comparable between the two detection systems, and the systematic errors between the two detection systems are clinically acceptable.

    Release date:2016-08-25 03:34 Export PDF Favorites Scan
  • Research on Recognizing Gastric Cancer Cell Based on Back Propagation Neural Network

    Objective To investigate the value of back propagation (BP) neural network for recognizing gastric cancer cell. Methods A total of 510 cells was selected from 308 patients. There were 210 gastric adenocarcinoma cells and 300 non-cancer gastric cells. Ten morphological parameters were measured for each cell. These data were randomly divided into two groups: training dataset (A) and test dataset (B). A three-layer BP neural network was built and trained by using dataset A. The network was then tested with dataset A and B.Results For data A, the sensitivity of network was 99%, specificity 99%, positive predictive value 98%, negative predictive value 99%, and accuracy 99%. For data B, the sensitivity of network was 99%, specificity 97%, positive predictive value 96%, negative predictive value 99%, the accuracy 98%. With receiver operator characteristic (ROC) curve evaluation, the area under ROC curve was 0.99.Conclusion The model based on BP neural network is very effective. A BP neural network can be used for effectively recognizing gastric cancer cell.

    Release date:2016-09-07 02:16 Export PDF Favorites Scan
  • Rotation Errors Due to Neck Deformation in Nasopharyngeal Cancer Radiotherapy with Image Guiding

    【摘要】 目的 利用不同匹配区域对锥形束CT(CBCT)与定位CT(FBCT)分别配准,测量出鼻咽癌放射治疗中颈部的变形误差。 方法 分析2007年4月-2008年12月收治鼻咽癌患者23例,调整治疗床前198次CBCT扫描。将鼻咽部扫描CBCT图像匹配区域分为上下两个区域进行对比分析。其中上匹配区域为:上界为蝶窦上缘,下界为颈4下缘,侧界包括下颌骨外轮廓,前界为上颌窦1/2,后界为平棘突后缘;下匹配区域为:上界约颈4下缘,下界约胸2-3下缘,侧界包括椎体外轮廓,前界包括皮肤,后界平棘突后缘。匹配方式选择骨,比较匹配结果差异。 结果 选择上与下匹配区域结果除Y(头脚)方向旋转误差无统计学差异外,余均有统计学差异(Plt;0.05) 。差值在X(左右)、Z(前后)、Y(头脚)方向平移分别为(1.14±2.80)、(0.47±1.41)、(0.58±3.88) mm,旋转误差X、Y、Z方向分别为(0.90±1.98)、(0.80±2.03)、(0.68±1.90)°。 结论 鼻咽癌放射治疗中颈部区域存在一定变形误差,通过CBCT引导发现变形误差并进行正确纠正是必须的,结合临床实际及靶区与危及器官的变化为重新计划提供依据。【Abstract】 Objective To investigate the rotation errors due to neck deformation in nasopharyngeal cancer (NPC) radiotherapy with different match areas to register conebeam CT(CBCT) from image guiding and fanbeam (FBCT) from simulation. Methods A total of 198 pre-correction CBCT data sets from 23 NPC patients from April 2007 to December 2008 were retrospectively analyzed. The matching areas in CBCT images were divided into up and down region of interest (ROI). For the up ROI, the superior, inferior, left and right, anterior, and posterior boundary were set parallel with sphenoid sinus up side, C4 down side, mandible outside, and 1/2 of maxillary air sinus and acanthi. For the down ROI, the lines were set parallel with C4 down side, T2-3 down side, neck outside, skin surface and acanthi respectively in all directions. All registrations were performed automatically by bony anatomy and the results were compared. Results The registration results by the up and the down ROI showed significant difference except Y direction for rotation. The translation error was (1.14±2.80),(0.47±1.41),and (0.58±3.88) mm, respectively; and the rotation error was (0.90±1.98),(0.80±2.03),and (0.68±1.90) ° in X, Y, and Z direction, respectively. 〖WTHZ〗Conclusions〖WTBZ〗There are some significant deformation errors at neck areas in NPC radiotherapy. It is important to find out the deformation and correct it with CBCT image guiding. This kind of error information may provide clues for re-planning in addition to clinical practice and the changes of clinical targets and involved organs.

    Release date:2016-08-26 02:21 Export PDF Favorites Scan
  • Interpretation of COSMIN risk of bias checklist in evaluating risk of bias of studies on reliability, measurement error and criteria validity of patient-reported outcome measures

    The COSMIN-RoB checklist includes three sections with a total of 10 boxes, which is used to evaluate risk of bias of studies on content validity, internal structure, and other measurement properties. COSMIN classifies reliability, measurement error, criteria validity, hypothesis testing for construct validity, and responsiveness as other measurement properties, which primarily focus on the quality of the (sub)scale as a whole, rather than on the item level. Among the five measurement properties, reliability, measurement error and criteria validity are the most widely used in the studies. Therefore, this paper aims to interpret COSMIN-RoB checklist with examples to guide researchers to evaluate the risk of bias of the studies on reliability, measurement error and criteria validity of PROMs.

    Release date:2020-12-25 01:39 Export PDF Favorites Scan
  • Assessment of the Accuracy of Continuous Glucose Monitoring and Its Correlated Factors

    【摘要】 目的 评价2型糖尿病(type 2 diabetes mellitus,T2DM)患者动态血糖监测(continuous glucose monitoring,CGM)的准确性及其相关因素。 方法 2009年1月—2010年1月共纳入患者530例,其中口服降糖药治疗者和胰岛素强化治疗者各265例。应用动态血糖监测系统(美国Medtronic MiniMed公司)连续监测3 d,同时每天输入4次指尖血糖值(self-monitoring of blood glucose,SMBG)进行校正。用直线回归分析CGM值与SMBG的相关性,用Clarke误差表格分析一致性,用平均绝对差(mean absolute relative difference,MAD)评价准确性,并分析MAD的相关因素。 结果 ①共收集到6 350对CGM值[(9.66±3.54) mmol/L]与SMBG值[(9.64±3.38) mmol/L],两者差异无统计学意义(Pgt;0.05)。Pearson相关性分析显示,两者呈正相关(r=0.959,Plt;0.001)。②Clarke误差表格分析显示:99.89%的点位于A区和B区,其中92.37%血糖值位于A区,7.72%位于B区,其余7对(0.11%)位于D区。③总体MAD值为7.2%(5.5%~9.5%),通过分析每天的MAD值见到,随着监测时间的延长,CGM结果的MAD值逐渐降低,而准确性逐渐升高。 ④胰岛素强化治疗组患者MAD值高于口服药治疗组患者(Plt;0.05),多元逐步回归分析显示,MAD值与糖化血清白蛋白水平呈独立负相关(β=-0.134, Plt;0.01),与胰岛素强化治疗呈独立正相关(β=0.117, Plt;0.05)。 结论 ①动态血糖与毛细血管血糖具有良好的相关性、一致性及准确性。 ②CGM结果的准确性除了受监测时间的影响外,还可能与患者的降糖治疗方案有关。【Abstract】 Objective To assess the accuracy of continuous glucose monitoring (CGM) for patients with type 2 diabetes mellitus (T2DM), and its correlated factors. Methods From January 2009 to January 2010, 530 patients with T2DM were enrolled in this study, including 265 subjects taking oral hypoglycemic agents and the other 265 subjects taking intensive insulin treatment. All the subjects underwent CGM (American Medtronic MiniMed) for three days. Meanwhile, capillary glucose values through self-monitoring of blood glucose (SMBG) were inputted four times a day for adjustment. The correlation of CGM value and capillary glucose value was analyzed by linear regression method. The consistency was analyzed by Clarke error grid. Mean absolute relative difference (MAD) was used to assess accuracy and correlated factors of MAD were also analyzed. Results ① A total of 6 350 pairs of CGM and SMBG values were collected [(9.66±3.54) mmol/L vs. 9.64±3.38) mmol/L,Pgt;0.05]. Pearson correlation analysis showed that CGM value was positively correlated with SMBG value (r=0.959,Plt;0.001). ② Clarke error grid demonstrated that 99.89% of paired SMBG-CGM values were located in zone A and zone B and the remaining seven pairs (0.11%) of glucose values were located in zone D. ③ The overall MAD value was 7.2% (5.5%-9.5%). According to the analysis of daily MAD value, MAD value decreased, while accuracy elevated gradually with monitoring time. ④ MAD value of intensive insulin treatment group was higher than that of the oral hypoglycemic agent treatment group (Plt;0.05). And stepwise multiple regression analysis indicated that MAD value had negative correlation with glycated albumin level (β=-0.134, Plt;0.01) and positive correlation with intensive insulin treatment (β= 0.117,Plt;0.05). Conclusions ① The results of CGM are accurate, and have good correlation and consistency with capillary glucose. ② Besides monitoring time, the accuracy of continuous glucose monitoring may be also associated with hypoglycemic treatment strategy.

    Release date:2016-09-08 09:26 Export PDF Favorites Scan
  • Analysis and Research on Grading Error in Nursing Basic Technique Examination

    【摘要】 目的 分析护理基本技能考核评分误差产生的原因。 方法 使用单因素方差分析法对我校高中起点三年制护理专业2006级440名学生及2007年某校护理专业高中起点三年制护理专业2006级281名学生的护理基本技能考核成绩进行分析,并从2006级440名学生中随机抽取129名学生利用自制问卷进行调查。 结果 考核项目和监考教师不同是造成学生护理基本技能考核成绩评分存在误差的主要原因。 结论 监考教师应统一并细化考核标准及制定护理基本技能考核项目难度系数。【Abstract】 Objective To analyze the reasons of grading error in nursing basic technique examination.  Methods The results of nursing basic technique examination of 440 three-year-college students in grade 2006 majored in nursing in Cangzhou Medical College and 281 three-year-college students in grade 2007 majored in nursing in Hebei Provincial Medical College were retrospectively analyzed by one-factor analysis of variance, and 129 students who were selected randomly from the students in grade 2006 were investigated via a self-made questionnaire. Results The reasons of grading error were different assessment items and different invigilators. Conclusion Unifying the difficulty level and the standard of the assessment may decrease the grading errors in nursing basic technique examination.

    Release date:2016-09-08 09:25 Export PDF Favorites Scan
  • Study on the inverse problem of electrical impedance tomography based on self-diagnosis regularization

    The inverse problem of electrical impedance tomography (EIT) is seriously ill-posed, which restricts the clinical application of EIT. Regularization is an important numerical method to improve the stability of the EIT inverse problem as well as the resolution of the imaging. This paper proposes a self-diagnosis regularization method based on Tikhonov regularization and diagonal weight regularization method (DWRM). Firstly, the ill-posedness of the inverse problem is analyzed by sensitivity. Then, the performance of the self-diagnosis regularization is analyzed through the singular value theory. Finally, some simulated experiments including simulations and flume experiment are carried out and verify that the self-diagnosis regularization has better image quality and anti-noise ability than those of traditional regularization methods. The self-diagnosis regularization method weakens the ill-posedness of inverse problem of EIT and can prompt the practical application of EIT.

    Release date:2018-08-23 03:47 Export PDF Favorites Scan
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