Feldkamp Cone-beam Reconstruction Algorithm Research Articles

Tilted plane Feldkamp type reconstruction algorithm for spiral cone beam CT

An approximate image reconstruction method for spiral cone beam computed tomography (CT), called tilted plane Feldkamp type reconstruction algorithm (TPFR), is presented in this paper, which extends Feldkamp cone beam reconstruction algorithm to deal with its inaccuracy and artifact problems caused by large cone angle. This is done by tilting the reconstructing planes to minimize the cone angle and optimally fit the spiral segment of the source. The tilted plane image reconstruction requires reforming the three-dimensional projection data set for the tilted plane and application of Feldkamp algorithm to the reformed data set. Analytical and computational results can show that the image reconstruction performance of the proposed TPFR algorithm is superior to that of the Feldkamp reconstruction algorithm in the image quality, volume coverage speed, maximum achievable pitch value, and slice sensitivity profiles. Moreover, it provides more accurate image reconstruction than the existing two-dimensional reconstruction algorithms.

Near Real-Time X-Ray Cone-Beam Microtomography

Abstract Due to the penetration ability and absorption contrast mechanism, cone-beam X-ray microtomography is a powerful tool in studying 3D microstructures in opaque specimens. In contrast to the conventional parallel and fan-beam geometry, the cone-beam tomography set up is highly desirable for faster data acquisition, build-in magnification, better radiation utilization and easier hardware implementation. However, the major draw back of the cone-beam reconstruction is its computational complexity. In an effort to maximize the reconstruction speed, we have developed a generalized Feldkamp cone-beam reconstruction algorithm to optimize the reconstruction process. We report here the use of curved voxels in a cylindrical coordinate system and mapping tables to further improve the reconstruction efficiency. The generalized Feldkamp cone-beam image reconstruction algorithm is reformulated utilizing mapping table in the discrete domain as: , where .

Cone-beam X-ray microtomography of small specimens

Microtomography is a technique for creating three-dimensional images of the internal structure of objects with high spatial resolution. This can potentially allow inspection of the architecture of breast lumpectomy specimens and visualisation of tumours in small animals and also has an application as a tool for nondestructive testing. An efficient method to perform microtomography is to use an area detector and cone-beam reconstruction techniques. Here the authors report on the development of an instrument for microtomography and show example images. The equipment consists of a microfocal X-ray tube (energies and currents up to 30 kVp, 0.2 mA, focal spot size <5 mu m), a rotating specimen stage and a high-resolution X-ray image intensifier optically coupled to a CCD video camera. Data acquisition and 3D image reconstruction are performed by a desktop computer. The well-known Feldkamp cone-beam reconstruction algorithm is used to produce tomographic images from the recorded X-ray projections. The instrument can image samples with diameters of 5-50 mm and create tomographic images with spatial resolution of the order 10-100 mu m and signal-to-noise ratio of better than 5:1. This work is a continuation and improvement of an earlier instrument with a low-energy X-ray source and detector.