Improved image reconstruction in positron emission tomography using a priori anatomical information

High resolution anatomical images provided by magnetic resonance imaging or X-ray computed tomography can be registered with functional images obtained from emission tomography, to obtain accurate anatomical localization of the functional images. The anatomical data provide prior knowledge which is used to infer radionuclide concentration in the organ of interest. In this paper, a maximum a posteriori estimation method is presented which uses this information to obtain improved image reconstructions. The a prior probability distribution of the radionuclide concentration is modelled by a Gibbs distribution. The contribution here is the introduction of a new 'potential function' that facilitates coding of the prior anatomical information in the reconstruction process. Computer simulations are presented which indicate marked improvements can be achieved in reconstructions when the prior information is used.