Dual-color tumor-host imaging models

髋关节中心（HJC）的估计通常基于解剖标志和人体测量指标（如骨盆宽度）的预测。人们担心这种方法在肥胖或骨盆畸形患者中的相关性。最近的研究探索估计HJC使用功能的方法。目前的文献往往未能披露这些测试中使用的算法的形式，虽然存在三种不同的形式。此外，以前的研究忽略了算法之间的相互作用，由数据表示的球面部分，数据中包含的噪声的性质和大小，以及不同标记放置策略的影响。本项目的目标是了解这些相互作用，以便了解何时临床实施功能方法是适当的，何时可能产生错误的结果。他的项目的具体目标是：1）将运动面积和径向扰动值建模为与功能算法相关联的误差的函数，2）确定运动面积对在非承重条件下测量的HJC估计的影响，3）确定标记放置对非承重条件下径向扰动和HJC估计的影响，4）将功能算法与来自预测方法的估计以及基于超声和DEXA成像的已知HJC位置进行比较，以及5）确定功能算法和标记放置策略对在负重期间测量的HJC估计的特性。在本研究的计算机建模部分中，将系统地改变髋关节屈曲/伸展、abd/add和随机径向噪声的范围，以生成质心位移图。从这些模拟中计算出的地图将用于 为算法在临床中的使用建立理论约束。在本研究的临床部分，将使用DEXA和超声确定HJC定位的标准。在站立和行走试验期间收集的运动分析数据将用于根据1）不同算法、2）不同虚拟膝关节标记重建方法和3）限定量的球面重建HJC。将分析与不同放置策略相关的标记噪声的特性。将所得HJC与标准品进行比较，以确定每个变量的相互作用，以及每个变量的可接受值范围，这些值将在标准品的1 cm范围内产生HJC。

Estimates of the hip joint centers (HJC) are usually based on predictions from anatomical landmarks and anthropometrical measures such as pelvic breadth. There is concern regarding the relevance of this approach in patients characterized by obesity or pelvic deformity. Recent investigations have explored estimating HJCs using the functional method. Current literature often fails to disclose the form of the algorithm used in these tests, although three distinct forms exist. In addition, previous research has ignored the interaction between the algorithms, the portion of sphere surface represented by the data, the nature and magnitude of noise contained in the data, and the effect of different marker placement strategies. The goal of this project is to understand these interactions in order to know when clinical implementation of the functional method is appropriate and when it is likely to produce erroneous results. The specific aims of his project are: 1) to model the area of motion and radial perturbation values as a function of the error associated with the functional algorithms, 2) to determine the effect of area of motion on HJC estimates measured under non weight-bearing conditions, 3) to determine the effect of marker placement on radial perturbations and HJC estimates under non weight-bearing conditions, 4) to compare the functional algorithms to estimates from prediction methods and with known HJC locations based on ultrasound and DEXA imaging, and 5) to determine the characteristics of functional algorithms and marker placement strategies on HJC estimates measured during weight-bearing. In the computer modeling component of this study, the range of hip flex/ext, abd/add, and random radial noise will be systematically altered in order to produce maps of the centroid displacement. The maps calculated from these simulations will be used to establish theoretical constraints for use of the algorithms in clinic. In the clinical component of the study, the standard for HJC location will be determined with DEXA and ultrasound. Motion analysis data collected during standing and walking trials will be used to reconstruct HJCs from 1) different algorithms, 2) different virtual knee marker reconstruction methods, and 3) delimited amounts of sphere surface. The characteristics of marker noise associated with different placement strategies will be analyzed. Resulting HJCs will be compared to the standard to determine the interactions of each variable, and the acceptable range of values from each variable that will produce HJCs within 1 cm of the standard.