Statistical limitations in transaxial tomography

A general analysis is presented of the limitations on transaxial tomographic imaging due to the quantum statistics of the radiation source. An idealized model is used in which reconstruction errors due to divergence of the X-ray beam, the finite number of projections, and the finite detector size are neglected. The results, therefore, represent an upper bound to the performance attainable with this method. An operator formalism is introduced to describe the various linear reconstruction algorithms, all of which are shown to be statistically equivalent. Expressions are derived for the mean signal, rms noise, resolution, and required radiation dose for a given signal-to-noise ratio. The results are valid for any object and any linear reconstruction algorithm.