Biophysical Science and Medical Physics, University of Minnesota, Minneapolis, MN 55455, USA.
Microsc Microanal. 2013 Aug;19(4):907-13. doi: 10.1017/S1431927613001396. Epub 2013 May 30.
The objective of this study is to determine the optimal physical parameters of a rotating gantry micro-CT system to assess in vivo changes to the trabecular bone of mice. Magnification, binning, peak kilovoltage, beam filtration, and tissue thickness are examined on a commercially available micro-CT system. The X-ray source and detector geometry provides 1.3×, 1.8×, or 3.3× magnification. Binning is examined from no binning to 2 to 4. Energy is varied from 40 to 80 kVp in 10 kVp increments and filter thickness is increased from no filtration to 1.5 mmAl in 0.5 mmAl increments. Mice are imaged at different magnifications and binning combinations to evaluate changes to image quality and microstructure estimation. Increasing magnification from 1.3× to 3.3× and lowering binning from 4 to 1 varies the spatial resolution from 2.5 to 11.8 lp/mm. Increasing the beam energy or filtration thickness decreases Hounsfield unit (HU) estimation, with a maximum rate of change being -286 HU/kVp for 80 kVp. Images for murine trabecular bone are blurred at effective pixel sizes above 60 μm. By comparing resolution, signal-to-noise ratio, and radiation dose, we find that a 3.3× magnification, binning of 2.80 kVp beam with a 0.5 mmAl filter comprises the optimal parameters to evaluate murine trabecular bone for this rotating gantry micro-CT.
本研究旨在确定旋转式龙门微计算机断层扫描系统的最佳物理参数，以评估小鼠小梁骨的体内变化。在商用微计算机断层扫描系统上检查放大倍数、 binning、峰值千伏、射线束过滤和组织厚度。X 射线源和探测器几何形状提供 1.3×、1.8×或 3.3×的放大倍数。Binning 从无 binning 到 2 到 4 进行检查。能量从 40 到 80 kVp 以 10 kVp 的增量变化，过滤厚度从无过滤增加到 1.5 mmAl，增量为 0.5 mmAl。在不同的放大倍数和 binning 组合下对小鼠进行成像，以评估图像质量和微观结构估计的变化。从 1.3×放大到 3.3×，并从 4 降低到 1，放大倍数的变化将空间分辨率从 2.5 变化到 11.8 lp/mm。增加射线束能量或过滤厚度会降低 Hounsfield 单位（HU）的估计值，最大变化率为 80 kVp 时为-286 HU/kVp。对于有效像素尺寸大于 60 μm 的小鼠小梁骨图像会变得模糊。通过比较分辨率、信噪比和辐射剂量，我们发现 3.3×的放大倍数、2.80 kVp 的 binning 以及 0.5 mmAl 的过滤是评估这种旋转式龙门微计算机断层扫描小鼠小梁骨的最佳参数。
