High-resolution x-ray imaging using Rowland-circle Bragg optics

A new approach to high-resolution imaging of radio-labeled agents based on Rowland circle x-ray optics is presented. Perfect-crystal Bragg optics is widely used in x-ray research due to its high reflectivity and excellent energy resolution. The nature of Bragg reflections directly correlates energy and spatial resolution, therefore yielding good imaging properties. Applied in a one to one focusing Rowland geometry, an array of spherically bent Bragg crystals can provide a large solid angle acceptance required for efficient imaging. The potential advantage over e.g. SPECT is twofold. First, focusing optics provides a ´virtual pinhole´ which can effectively be inside the object under investigation and does not suffer from edge effects and scattering. Second, Bragg optics has an energy resolution of a few eV and discriminates against inelastic Compton scattering, a common source for image blurring. Studies using ⁵⁵Fe and ^95mTc phantoms are presented, where a spatial resolution of less than 1 mm and 2 mm was achieved respectively.