Scattered X-rays in medical diagnostics

The VolumeScope, a prototype X-ray scanner based on Compton backscatter detection, is described. The device was designed for measurement of 3D electron density distribution of biological objects. General principles and technical parameters of the device are presented. A few test phantoms and biological objects were examined to evaluate an image quality of the device: a human forearm phantom, a CT calibration phantom and a young pig. 3D electron density distributions were reconstructed and represented as gray-scale sections and 3D surfaces of internal structures. Cartilages, bones, and other internal objects inside the pig head are well visible. Electron density contrast of bones in the objects is in qualitative agreement with real parameters of used tissue-equivalent materials. Some underestimation of the electron density was obtained in deep slices and most pronounced under the bones.