Cone-beam Micro-CT Using Flat-panel Detector

Computed Tomography(CT) is one of the key technologies in contemporary medical image and nondestructive testing. The art of medical CT is evolving rapidly and the last years have seen micro-CT systems with flat-panel detectors. These tomographs are able to collect high resolution three-dimensional datasets of small samples. Flat-panel micro-CT systems have merits of high-resolution, easier in image processing, smaller cubage, lower dose, etc.; which make the systems perfect for scanning small samples in medical images.Based on a micro-CT prototype, key technologies in designing flat-panel micro-CT systems have been researched here. Projective method has been applied for measuring the accurate position of X-ray source relative to the flat-panel detector. Because the detector is combined with two CCD instruments, a mathematic method is founded here to measure the otherness of the two CCD. To the question of fixed platform of micro-CT systems, cone-beam reconstruction formulas with a nonstationary shift of X-ray source are represented .Voltage of X-ray source used here is 10～35 kV, hard-beam effect is measured and adjusted in cone-beam reconstruction algorithms. To make reconstruction more rapidly with non-decreased image quality, half-scan FDK algorithm has been applied in software. Through micro-CT collecting projective images of samples, the software can reconstruct any part of three-dimensional dataset of samples with normal personal computers. Slice images and visualization of three-dimensional datasets showed the good performance of the micro-CT system and the capability of scanning small samples with high resolution.