Precision and Accuracy of Measurements on CT Scout View

ObjectivesThe purposes of this study were to (1) investigate the limits of measurements on scout view in three computed tomography axes, x, y and z and (2) develop a model to provide better understanding of measurement accuracy.MethodsFor the first objective, anteroposterior and lateral scout views of a Catphan phantom 200 mm in diameter and length were acquired with a GE scanner at 21 different table heights. Phantom measurements on scout view were performed by two experienced readers. The comparison of their measures provided estimation of precision. The accuracy was assessed by determining the bias, calculated as the difference between the values measured on scout view and the real phantom size. Second, a model was developed investigating the relationship between the dimensions of the object, its image, and the table height. This relationship was tested on our data.ResultsScout view measurements were precise, with less than 0.53% difference between readers. In addition, small biases of about 1 mm were detected in the z-axis, whatever the table height. In the other axes, serious biases from −13 to +73 mm were measured. Furthermore, at isocentre, overestimations up to 7 mm were shown. The results also indicated that biases in scout view measurements are because of the geometrical projection related to the object-detector distance.ConclusionsMeasurements in the table movement axis are precise and accurate, conferring to scout views an added value for preoperative planning in orthopedic surgery.     

Validation of PATHFx 2.0: An open-source tool for estimating survival in patients undergoing pathologic fracture fixation

Treatment decisions in patients with metastatic bone disease rely on accurate survival estimation. We developed the original PATHFx models using expensive, proprietary software and now seek to provide a more cost-effective solution. Using open-source machine learning software to create PATHFx version 2.0, we asked whether PATHFx 2.0 could be created using open-source methods and externally validated in two unique patient populations. The training set of a well-characterized, database records of 189 patients and the bnlearn package within R Version 3.5.1 (R Foundation for Statistical Computing), was used to establish a series of Bayesian belief network models designed to predict survival at 1, 3, 6, 12, 18, and 24 months. Each was externally validated in both a Scandinavian (n = 815 patients) and a Japanese (n = 261 patients) data set. Brier scores and receiver operating characteristic curves to assessed discriminatory ability. Decision curve analysis (DCA) evaluated whether models should be used clinically. DCA showed that the model should be used clinically at all time points in the Scandinavian data set. For the 1-month time point, DCA of the Japanese data set suggested to expect better outcomes assuming all patients will survive greater than 1 month. Brier scores for each curve demonstrate that the models are accurate at each time point. Statement of Clinical Significance: we successfully transitioned to PATHFx 2.0 using open-source software and externally validated it in two unique patient populations, which can be used as a cost-effective option to guide surgical decisions in patients with metastatic bone disease.     

铁路系统医院136篇口腔修复、正畸学论文的统计分析

通过对铁路系统医院１３６篇口腔修复、正畸学论文的统计分析，来评价医院口腔修复、正畸的科研水平，同时也揭示了科研工作中存在的问题。指出只有加强科研协作、扩大学术交流、增加科研投入，提高科研水平，使科研成果更趋完善。     

阿拉善黄鼠疫源地动物鼠疫预报的数学模型

根据我国阿拉善黄鼠鼠疫自然疫源地1981～1993年鼠疫监测资料，采用多元逐步曲线回归分析，建立了预报阿拉善黄鼠鼠疫流行的数学模型，其拟合率为100%，并得出影响鼠疫流行的主要因子为黄鼠密度和巢蚤指数。     

摆动筛运动的数学分析

本文分析了摆动筛的运动规律,并计算了位移、速度和加速度,分析了筛面上颗粒物体的受力情况,可供设计、制造和使用作参考。     

Using Computer Simulated Results of a Bulk Drug Substance Assay to Determine Acceptance Criteria for Method Validation

Purpose. To determine the statistical variability expected for a well designed HPLC assay of a bulk drug substance (BDS). The results are used to develop appropriate acceptance criteria for a method validation protocol as well as to evaluate the level of uncertainty expected for assay results using a variety of sampling/injection schemes. Methods. Computer simulation was used to generate a large quantity of data and the variability of the mock results was evaluated. Error propagation was also calculated, whenever possible, to confirm results obtained from the simulations. Results. Protocol acceptance criteria were developed that were consistent with the expected variability for data resulting from the execution of the validation protocol. In certain cases simulations provided the only avenue of obtaining results that could not otherwise be readily determined. Conclusions. Computer modeling can be used to obtain suitable acceptance criteria for validation results which are consistent with method variability. This is particularly significant in the case of linearity where it has been difficult to develop acceptance criteria based on anything other than analyst intuition and experience. Assay simulations clearly demonstrated that the variability expected for a typical BDS assay is large relative to the average specification range and therefore little insight about relative purity can be gained comparing individual passing assay results.     

Novel ROC-type method for testing the efficiency of multivariate statistical methods in fMRI.

The receiver operating characteristic (ROC) method is a useful and popular tool for testing the efficiency of various diagnostic tests applicable to functional MRI (fMRI) data. Typically, the diagnostic tests are applied on simulated and pseudo-human fMRI data, and the area under the ROC curve is used as a measure of the efficiency of the diagnostic test. The effectiveness of such a method depends on how well the simulated data approximate the real data. For multivariate statistical methods, however, this technique is usually inadequate, as the spatial dependence among voxels is ignored for simulated data. In this work a modified ROC method using real fMRI data with a broader scope is proposed. This method can be applied to most fMRI postprocessing techniques, including multivariate analyses such as canonical correlation analysis (CCA). Also, the relationship of the modified ROC method with the conventional ROC method is discussed in detail.     

医院统计在医院要素分配中的作用

目的 为支持医院内部要素分配调整改革，医院统计应展开与要素分配有关的项目进行统计，为医院要素分配向高、精、尖、绩效好的医务人员倾斜提供统计数据。方法 应用ExCEL软件的合并功能对病人信息和病案信息进行深层次的挖掘、提取、重新整合统计，制成简明易懂的统计报表给予反馈公布，作为医师提取个人奖酬、职称晋升或聘任竞岗的考核依据。结果通过统计作用实现了劳动价值创造，调动了广大医务人员的积极性，促使医院经营理念成为引导个人自觉行为的杠杆，实现了医院提高综合竞争实力的整体效应。结论 要素分配中统计工作应遵循公平、合理、反映医院经营理念的原则和利用网络科技实现高效管理并且应与改革同步，深化统计内涵，完善医院的统计方法。