Sampling strategies and resolution in limited data cone-beam tomography

This paper addresses the prediction of tomographic capabilities of limited-data cone-beam tomographic systems. We introduce the notion of "local directional resolution" to predict these capabilities and illustrate its usefulness in a simulation of SPECT breast imaging. The paper considers cone-beam tomography from limited data. Cone-beam tomography is a technique used to visualize the interior of a three-dimensional (3-D) object in a non-invasive way. This technique involves two steps. In the first step, measurements called cone-beam projections are taken. In the second step, digital signal processing techniques are used to process the measurements to form a 3-D image. The 3-D image represents a function f (x_) which associates each voxel x_ in the object with the value of a physical quantity. In X-ray imaging, this quantity is the X-ray attenuation factor which roughly corresponds to the density of the object. In single photon emission computed tomography (SPECT), the physical quantity is the concentration of a radioactive tracer injected into the 3-D object (the patient)