School of Electrical Engineering and Computer Science, ASRI, Seoul National University, Seoul, 151-744, South Korea.
J Digit Imaging. 2012 Feb;25(1):110-20. doi: 10.1007/s10278-011-9384-z.
In this paper, we present an effective method to determine the reference point of symphysis pubis (SP) in an axial stack of CT images to facilitate image registration for pelvic cancer treatment. In order to reduce the computational time, the proposed method consists of two detection parts, the coarse detector, and the fine detector. The detectors check each image patch whether it contains the characteristic structure of SP. The coarse detector roughly determines the location of the reference point of SP using three types of information, which are the location and intensity of an image patch, the SP appearance, and the geometrical structure of SP. The fine detector examines around the location found by the coarse detection to refine the location of the reference point of SP. In the experiment, the average location error of the propose method was 2.23 mm, which was about the side length of two pixels. Considering that the average location error by a radiologist is 0.77 mm, the proposed method finds the reference point quite accurately. Since it takes about 10 s to locate the reference point from a stack of CT images, it is fast enough to use in real time to facilitate image registration of CT images for pelvic cancer treatment.
在本文中，我们提出了一种在 CT 图像轴堆栈中确定耻骨联合（SP）参考点的有效方法，以方便骨盆癌治疗的图像配准。为了减少计算时间，所提出的方法包括两个检测部分，粗检测器和细检测器。这些检测器检查每个图像块是否包含 SP 的特征结构。粗检测器使用三种类型的信息大致确定 SP 参考点的位置，这三种信息是图像块的位置和强度、SP 的外观以及 SP 的几何结构。细检测器检查粗检测找到的位置周围，以细化 SP 参考点的位置。在实验中，该方法的平均位置误差为 2.23 毫米，大约是两个像素的边长。考虑到放射科医生的平均位置误差为 0.77 毫米，该方法可以非常准确地找到参考点。由于从 CT 图像堆栈中定位参考点大约需要 10 秒，因此其速度足够快，可以实时使用，以方便骨盆癌治疗的 CT 图像配准。
