Esthappan J, Harauchi H, Hoffmann K R
Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, University of Chicago, Illinois, USA.
Med Phys. 1998 Jun;25(6):965-75. doi: 10.1118/1.598275.
A technique is developed that will calculate accurate and reliable imaging geometries and three-dimensional (3D) positions from biplane images of a calibration phantom. The calculated data provided by our technique will facilitate accurate 3D analysis in various clinical applications. Biplane images of a Lucite cube containing lead beads 1 mm in diameter were acquired. After identifying corresponding beads in both images and calculating their image positions, the 3D positions of the beads relative to each focal spot were determined. From these data, the transformation relating the 3D configurations were calculated to give the imaging geometry relating the biplane views. The 3D positions of objects were determined from the biplane images along with the corresponding imaging geometries. In addition, methods are developed to evaluate the quality of the calculated results on a case-by-case basis in the clinical setting. Methods are presented for evaluating the reproducibility of the calculated geometries and 3D positions, the accuracy of calculated object sizes, and the effects of errors due to time jitter, variation in user-indication, centering, and distortions on the calculated geometries and 3D reconstructions. The precision of the translation vectors and rotation matrices of the calculated geometries were within 1% and 1 degree, respectively, in phantom studies, with estimated accuracies of approximately 0.5% and 0.4 degree, respectively, in simulation studies. The precisions of the absolute 3D positions and orientations of the calculated 3D reconstructions were approximately 2 mm and 0.5 degree, respectively, in phantom studies, with estimated accuracies of approximately 1.5 mm and 0.4 degree, respectively, in simulation studies. This technique will provide accurate and precise imaging geometries as well as 3D positions from biplane images, thereby facilitating 3D analysis in various clinical applications. We believe that the study presented here is unique in that it represents the first steps toward understanding and evaluating the reliability of these 3D calculations in the clinical situation.
开发了一种技术，该技术将根据校准体模的双平面图像计算准确可靠的成像几何形状和三维（3D）位置。我们的技术提供的计算数据将有助于在各种临床应用中进行准确的3D分析。采集了包含直径1mm铅珠的有机玻璃立方体的双平面图像。在识别出两幅图像中的对应珠子并计算它们的图像位置后，确定珠子相对于每个焦点的3D位置。根据这些数据，计算出与3D配置相关的变换，以给出与双平面视图相关的成像几何形状。从双平面图像以及相应的成像几何形状中确定物体的3D位置。此外，还开发了在临床环境中逐案评估计算结果质量的方法。提出了评估计算几何形状和3D位置的可重复性、计算物体尺寸的准确性以及时间抖动、用户指示变化、对中以及失真对计算几何形状和3D重建的误差影响的方法。在体模研究中，计算几何形状的平移向量和旋转矩阵的精度分别在1%和1度以内，在模拟研究中估计精度分别约为0.5%和0.4度。在体模研究中，计算的3D重建的绝对3D位置和方向的精度分别约为2mm和0.5度，在模拟研究中估计精度分别约为1.5mm和0.4度。该技术将从双平面图像中提供准确精确的成像几何形状以及3D位置，从而便于在各种临床应用中进行3D分析。我们认为，此处提出的研究具有独特性，因为它代表了在临床情况下理解和评估这些3D计算可靠性的第一步。
