Multiple Photon Interactions in the Compton Scattering Measurement of Lung Density

The Compton scattering measurement of lung density using an external source relies on the linear dependence of the number of singly scattered photons on electron density. Multiply scattered photons are however inherently present in the spectrum and lead to significant errors even for objects of known geometry and composition. The properties and extent of the multiple scattering contribution are investigated and methods by which it may be accounted for in the lung density system are explored.