CONE-BEAM X-RAY MICROTOMOGRAPHY OF SMALL SPECIMENS

Microtomography is a technique for creating three-dimensional images o f the internal structure of objects with high spatial resolution. This can potentially allow inspection of the architecture of breast lumpec tomy specimens and visualization of tumours in small animals and also has an application as a tool for non-destructive testing. An efficient method to perform microtomography is to use an area detector and cone -beam reconstruction techniques. In this paper we report on the develo pment of an instrument for microtomography and show example images. Th e equipment consists of a microfocal x-ray tube (energies and currents up to 30 kV(p), 0.2 mA, focal spot size < 5 mu m), a rotating specime n stage and a high-resolution x-ray image intensifier optically couple d to a CCD video camera. Data acquisition and 30 image reconstruction are performed by a desktop computer. The well-known Feldkamp cone-beam reconstruction algorithm is used to produce tomographic images from t he recorded x-ray projections. The instrument can image samples with d iameters of 5-50 mm and create tomographic images with spatial resolut ion 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 instrum ent with a low-energy x-ray source and detector.