A Conway-Maxwell-Poisson (CMP) model to address data dispersion on positron emission tomography

The deviation from Poisson statistics in PET data could be described by the Conway-Maxwell-Poisson (CMP) distribution model, which is characterized by the centring parameter 2 and the dispersion parameter nu, the latter quantifying the deviation from a Poisson distribution model. In particular, the parameter nu allows quantifying over-dispersion (nu < 1) or under-dispersion (nu > 1) of data. A simple and efficient method for lambda and nu parameters estimation is introduced and assessed using Monte Carlo simulation for a wide range of activity values.