The MARS scanner incorporates the Medipix detector chip, a new generation x-ray detector. It is both energy resolving and photon counting which allows true quantitative images. It has been developed by the Medipix3 Collaboration, which comprises CERN in Geneva and 18 research institutions worldwide.
Spectral imaging offers to revolutionize the field of CT and provide a significant new technology platform for diagnostic imaging. MARS promises not only images with new and improved diagnostic information, but allows faster and lower cost radiology procedures while working with significantly lower radiation dose. This will significantly broaden both the value and use of CT as a diagnostic tool.
The MARS spectral molecular imaging technology is based on counting the number of photons at multiple narrow energy bands. This is often referred to as spectral, spectroscopic or multi-energy imaging. The Medipix chip is made up of a specially fabricated CMOS semiconductor chip with a detector material bonded to it. Each chip has 65,536 pixels. Every pixel accurately counts the number of photons that reach it within specified energy bands. Black and white CT cannot distinguish different density tissue as they absorb similar amounts of photons. MARS advances this as body tissue of similar density interacts differently with certain energies. The Medipix chip can detect these different interactions. In addition the energy of a photon can change based on interactions with the electron shells of the atoms in the body tissues it encounters. These effects mean that information about both the density and the atomic make-up of a tissue can be imaged and can be assigned to colors on an image.