The determination of electron density by the dual-energy Compton scatter method.

The intensity of Compton scattered photons is directly proportional to the electron density of a substance; therefore it is possible to detect changes in electron density by this noninvasive method. The source-detector geometry has been varied to study the effects of geometry on the calculated electron density values, using a 90 degrees scattering angle. The dual-energy Compton scatter method provides a determination of electron density in known samples, with an uncertainty of less than 1% for the optimal geometry. The effective linear attenuation coefficient for Compton scatter has been determined with an uncertainty of 2.1%-3.6% for the optimal geometry used. The applications of the dual-energy Compton scattering technique in radiotherapy dosimetry and skeletal bone densitometry are being investigated.