Schematic describing the developed micro-CT system. The x-ray source continuously irradiates an object fixed onto a jig, which is rotated at a constant angular velocity, and the 2D imaging detector acquires a projection view at a given integration time. All the operations of components are computer controlled. The source status, such as potential and current, is separately monitored. Two variable distances, SOD and SDD, determine the system magnification factor, the actual cone-beam angle, and FOV of the object.
Homemade phantoms to evaluate the tomographic imaging performance of the micro-CT system. (a) The cylindrical acrylic vessel, which contains water, is scanned for the estimation of the voxel noise and SNR. (b) Low-contrast inserts, which are immersed in water inside the cylindrical acrylic vessel and scanned for the estimation of CNR. Each insert has three different diameters: 1.5, 3.0, and 5.0 mm.
Fourier analyses for the imaging characteristics of the CMOS detector. (a) The measured system MTF and theoretical MTFs representing physical parameters affecting the overall MTF, the focal spot of x-ray source, the pixel aperture of detector, and the width of slit camera. (b) The measured NNPS and the least-squares fits to analyze the NNPS. (c) The measured DQE.
Radiograph of the line-pair test phantom, which supports the result of measured MTF.
Cross-sectional images of the contrast phantom with respect to various imaging parameters, such as the dose, the diameters of inserts, and the slice thickness. Reference images of (a)–(c) depict the effect of the insert diameter, (d) and (e) the effect of the dose, and (f) and (g) the effect of the slice thickness. Note that and denote the insert diameter and the slice thickness, respectively.
The CNR, calculated from the images obtained for low-contrast inserts having a diameter of 1.5 mm, as a function of dose. The dotted lines are trend curves that are proportional to the square root of the dose.
The SNR, calculated from the images obtained for the water phantom, as a function of dose. The solid lines show a trend curve proportional to the square root of the dose.
Screenshot of the main window describing the developed graphical toolbox.
Experimental simulation with a chessman, bishop, using the developed toolkit. (a) Original CAD data, which were as an input file for the RP machine, and the manufactured RP bishop sample. (b) 3D-rendered images of voxel data obtained from the CT scan. Two different visualizations, ray casting, and MIP, are shown. (c) Extracted CAD files from the voxel data by using the developed toolkit. The left is the extracted, as is, and the right is after decimation and smoothening processes. (d) A map describing the difference between the original and the extracted CAD files.
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