A simple data loss model for positron camera systems

A simple model to describe data losses in PET cameras is presented. The model is not intended to be used primarily for dead time corrections in existing scanners, even if this may be possible. Instead the model is intended to be used for data simulations in order to determine the figures of merits of future camera systems based on data handling state-of-art solutions. The model assumes the data loss to be factorized into two components, one describing the detector or block-detector performance and the other the remaining data handling such as coincidence determinations, data transfer and data storage. Two modern positron camera systems have been investigated in terms of this model. These are the new Siemens-CTI systems, Ecat Exact and Ecat Exact HR, both with an axial field-of-view (FOV) covering around 15 cm. They both have retractable septa and can acquire data from the whole volume within the FOV and can reconstruct volume image data. An example is given how to use the model for live time calculations in a futuristic large axial FOV cylindrical system