Evolution of PIRL Micro-CT Scanning

  • Our First Micro-CT Scanner

    Basic configuration of our first micro-CT scanner, built in 1993 for scanning specimens. The specimen rotates within a stationary x-ray source/detector array x-ray image system. The x-ray image-to-light conversion is performed by a thin CsI (Tl) crystal layering deposited on a thin, transparent, glass-like window. This light image is projected onto the CCD imaging array via an optical lens. Magnification of the x-ray image is achieved altering the lens position between the CsI and CCD. Because the x-ray source is a relatively long way from the specimen and the specimen is relatively close to the CsI crystal plate, the x-ray focal spot size can be fairly large, thus allowing increased power.

  • Micro-CT 2
    Micro-CT 2

    This system consists of an x-ray source with a small focal spot and a flat panel, large array, x-ray imaging detector. Large specimens can be imaged or movement of the x-ray source towards the specimen can be used to magnify the image. This system can also be used to record the small angle (coherent) x-ray scatter from within a specimen when it is illuminated by a pencil or, a 1D collimator grid is used, a sheet beam of x-ray. In this system the specimen is rotated or translated.

  • Medipix Spectral X-ray Imaging Detector Array
    Medipix Spectral X-ray Imaging Detector Array

    Our most recent acquisition is a Medipix spectral x-ray imaging detector array –based micro-CT scanner. In this scanner the specimen (or small animal) lies horizontally centered on the axis of rotation of the rotating x-ray source and its opposing imaging array. The imaging array provides direct x-ray to current conversion, photon counting and energy allocation of the photons. This makes it particularly useful for dual energy (esp. K edge) subtraction imaging.

  • Multi-source Micro-CT Scanner
    Multi-source Micro-CT Scanner

    In the future we need to image transient events such as the passage of a bolus of contrast agent, peristalsis of the gut or ureters or the beat to beat variation of cardiac contraction when there is an irregular heart cycle. In order to reduce scan time to less then 50 msec a multi-source Micro-CT scanner has been designed. It is a micro-CT version of the previously built Dynamic Spatial Reconstructor — a multi-x-ray source/detector scanner that performed scans in 10 msec with a 60/sec repetition rate. This micro-CT scanner will involve, for instance, 12 x-ray source-detector array pairs arranged on a semi-circle around 165° at 15° intervals. This arrangement can acquire a 180 degree scan data set in <50 msec when it rotates at 1 rotation per second. This speed is needed to provide 3D images of non-reproducible transient events which cannot be imaged in a mode gated to a physiological signal such as the ECG or diaphragmatic movement.