Anam Choirul, Naufal Ariij, Dwihapsari Yanurita, Fujibuchi Toshioh, Dougherty Geoff
Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Tembalang, Semarang, Central Java, Surabaya, East Java, Indonesia.
Department of Physics, Faculty of Science and Data Analytics, Sepuluh Nopember Institute of Technology (ITS), Kampus ITS Sukolilo, Surabaya, East Java, Indonesia.
J Med Phys. 2024 Jan-Mar;49(1):103-109. doi: 10.4103/jmp.jmp_155_23. Epub 2024 Mar 30.
The slice spacing has a crucial role in the accuracy of computed tomography (CT) images in sagittal and coronal planes. However, there is no practical method for measuring the accuracy of the slice spacing.
This study proposes a novel method to automatically measure the slice spacing using the American Association of Physicists in Medicine (AAPM) CT performance phantom.
The AAPM CT performance phantom module 610-04 was used to measure slice spacing. The process of slice spacing measurement involves a pair of axial images of the module containing ramp aluminum objects located at adjacent slice positions. The middle aluminum plate of each image was automatically segmented. Next, the two segmented images were combined to produce one image with two stair objects. The centroid coordinates of two stair objects were automatically determined. Subsequently, the distance between these two centroids was measured to directly indicate the slice spacing. For comparison, the slice spacing was calculated by accessing the slice position attributes from the DICOM header of both images. The proposed method was tested on phantom images with variations in slice spacing and field of view (FOV).
The results showed that the automatic measurement of slice spacing was quite accurate for all variations of slice spacing and FOV, with average differences of 9.0% and 9.3%, respectively.
A new automated method for measuring the slice spacing using the AAPM CT phantom was successfully demonstrated and tested for variations of slice spacing and FOV. Slice spacing measurement may be considered an additional parameter to be checked in addition to other established parameters.
层厚间距在计算机断层扫描（CT）矢状面和冠状面图像的准确性中起着关键作用。然而，目前尚无测量层厚间距准确性的实用方法。
本研究提出一种使用美国医学物理学家协会（AAPM）CT性能模体自动测量层厚间距的新方法。
使用AAPM CT性能模体模块610 - 04测量层厚间距。层厚间距测量过程涉及该模块的一对轴向图像，其中包含位于相邻切片位置的斜坡状铝质物体。对每个图像中的中间铝板进行自动分割。接下来，将两个分割后的图像合并，生成一个带有两个阶梯状物体的图像。自动确定两个阶梯状物体的质心坐标。随后，测量这两个质心之间的距离，以直接指示层厚间距。为作比较，通过访问两个图像的DICOM头文件中的切片位置属性来计算层厚间距。所提出的方法在具有不同层厚间距和视野（FOV）的模体图像上进行了测试。
结果表明，对于层厚间距和FOV的所有变化，层厚间距的自动测量都相当准确，平均差异分别为9.0%和9.3%。
成功展示并测试了一种使用AAPM CT模体测量层厚间距的新自动化方法，该方法可用于不同层厚间距和FOV的情况。除了其他既定参数外，层厚间距测量可被视为一个需要检查的附加参数。
