Construction and Operation of the MARS-CT Scanner

The aim of this project is to build a spectroscopic CT scanner capable of taking multiple energy CT images of small animal and pathology specimens. The current prototype scanner uses a conventional x-ray tube and a Medipix2 x-ray detector (developed by the European Organisation for Nuclear Research - CERN) that is capable of photon counting and energy discrimination. The scanner is referred to as the Medipix All Resolution System-CT (MARS-CT). We designed and constructed the gantry and control electronics so that the detector and x-ray tube could be rotated around an object of up to 100 mm diameter. Software was written to control the scanner and reconstruct the spectroscopic projection data into a 3D volume, using cone beam filtered back projection. The scanner successfully takes 3D images at 43 µm resolution. The use is able to define the energy ranges known as energy bins. The scanner's stability, accuracy and image quality was proven and tested. We successfully scanned a range of small objects including mice