Fleming J S, Alaamer A S
Department of Medical Physics, Southampton General Hospital, UK.
Phys Med Biol. 1998 Aug;43(8):2309-23. doi: 10.1088/0031-9155/43/8/022.
Robust techniques for automatic or semi-automatic segmentation of objects in single photon emission computed tomography (SPECT) are still the subject of development. This paper describes a threshold based method which uses empirical rules derived from analysis of computer simulated images of a large number of objects. The use of simulation allowed the factors affecting the threshold which correctly segmented objects to be investigated systematically. Rules could then be derived from these data to define the threshold in any particular context. The technique operated iteratively and calculated local context sensitive thresholds along radial profiles from the centre of gravity of the object. It was evaluated in a further series of simulated objects and in human studies, and compared to the use of a global fixed threshold. The method was capable of improving accuracy of segmentation and volume assessment compared to the global threshold technique. The improvements were greater for small volumes, shapes with large surface area to volume ratio, variable surrounding activity and non-uniform distributions. The method was applied successfully to simulated objects and human studies and is considered to be a significant advance on global fixed threshold techniques.
单光子发射计算机断层扫描（SPECT）中用于自动或半自动分割物体的稳健技术仍在不断发展。本文描述了一种基于阈值的方法，该方法使用从大量物体的计算机模拟图像分析中得出的经验规则。模拟的使用使得能够系统地研究影响正确分割物体的阈值的因素。然后可以从这些数据中得出规则，以在任何特定情况下定义阈值。该技术迭代运行，并沿着从物体重心出发的径向轮廓计算局部上下文敏感阈值。它在一系列进一步的模拟物体和人体研究中进行了评估，并与使用全局固定阈值进行了比较。与全局阈值技术相比，该方法能够提高分割精度和体积评估。对于小体积、表面积与体积比大的形状、可变的周围活性和不均匀分布，改进更为显著。该方法已成功应用于模拟物体和人体研究，被认为是全局固定阈值技术的重大进步。
