Compton scatter imaging of transverse sections: corrections for multiple scatter and attenuation.

The electron density (e cm-3) of a tissue sample can be determined by measuring the fluence of photons which it Compton scatters from a narrow incident beam of X- or gamma-radiation. This technique has been applied successfully to diagnostic denistometry (bone, lung), and less successfully to whole body tomography. In this work, the physics of Compton scatter tomography is examined with emphasis on transverse section scanning. The two major limitations of the scatter technique, attenuation of the single scatter photon fluence (of interest), and contamination of this fluence by multiply-scattered photons, are studied and corrective procedures are proposed. The methods described are applied to a simple test phantom; it is concluded that transverse images with an electron density precision of approximately 5% are possible.