A 3D microtomographic system with stacked fan-beam geometry

The move from 2D to 3D analysis, and the increase in spatial resolution cha racterize recent improvements in CT-based structure assessment. A new deskt op micro-CT system with high scanning speed has been developed. The instrum ent makes use of a novel multiple fan-beam technique: radiation from a line -focus X-ray tube is divided into a stack of fan-beams by a foil collimator with a 30 mu m pitch. The stacked fan-beam geometry allows to design compa ct CT scanners with a source-to-detector distance of only 18 cm. The comple te system fits into a standard 19 in. rack. Image reconstruction is based o n standard fan-beam algorithms, which eliminates the difficulties and limit ations associated with cone-beam reconstruction. The detector comprises a l ow-noise area CCD sensor, a fiber-optic light guide and a scintillator scre en. A complete examination requires 2 min only. The new micro-CT system has a voxel size of 20 x 20 x 26 mu m(3). Each 3D image contains a quarter of a billion voxels or a multiple of it. Samples up to 20 mm in diameter and u p to 40 mm in length can be imaged. The instrument can be operated in a nor mal lab environment. (C) 2000 Elsevier Science B.V. All rights reserved.