ABSTRACT

Microcomputed tomography (CT) is a three-dimensional x-ray imaging technique based upon the principles of clinical CT. Specialized equipment has become available that tailors the micro-CT scanner to high-resolution imaging of small objects or small animals. Micro-CT scanners all consist of an x-ray source, an area detector, and a means of producing images at regularly spaced angular intervals around the object being imaged. Prototype micro-CT scanners built in individual research labs can be more flexible in adopting new technologies, such as carbon nanotube field emission micro-focus x-ray sources. There are two categories of detectors employed in micro-CT imaging: indirect and direct conversion detectors. Indirect detectors have some similarities with film-screen imaging by employing a phosphorescent material as a conversion layer that is often made from the same material as x-ray screen. Direct conversion detectors absorb the incident x-rays, creating charge pairs that are separated to opposing sides of the detector using a bias voltage.