A new X-ray computed tomography system for laboratory mouse imaging

Two versions of a new high-resolution x-ray computed tomography system are being developed to screen mutagenized mice in the Oak Ridge National Labora tory Mammalian Genetics Research Facility. The first prototype employs a si ngle-pixel cadmium zinc telluride detector with a pinhole collimator operat ing in pulse counting mode. The second version employs a phosphor screen/CC D detector operating in current mode. The major system hardware includes a low-energy x-ray tube, two linear translation stages and a rotational stage . For the single-pixel detector, image resolution is determined by the step size of the detector stage; preliminary images have been acquired at 100 I rm and 250 mu m resolutions. The resolution of the phosphor screen detector Is determined by the modulation transfer function of the phosphor screen; images with resolutions approaching 50 mu m have been acquired. The system performance with the two detectors is described and recent images are prese nted.