Patent Document ID: 8676744
Application ID: 12259198
Patent Flag: 1

Claim One:
1. A photon-by-photon sequential radionuclide detection method comprising: detecting an event mode sequence (EMS) comprising a sequence of measured photon events each uniquely characterized by an energy amplitude-interarrival time parameter pair; for an n th photon event of the EMS: selecting a monoenergy processing channel from a set of parallel monoenergy processing channels derived from a monoenergetic decomposition of a target radionuclide into monoenergetic sources in which to process the n th photon event, said selection based on a determination that both of the energy amplitude and interarrival time values of the n th photon event satisfy respective energy amplitude and interarrival time confidence interval conditions of the selected monoenergy channel; upon selecting the monoenergy channel, using a sequential Bayesian processor of said selected monoenergy channel to update energy amplitude and interarrival time parameter estimates with the measured energy amplitude and interarrival time values of the nth photon event; using the updated amplitude and interarrival time parameter estimates to update a measured probability density function (PDF) estimate for the target radionuclide; determining whether a sequential likelihood ratio satisfies one of two threshold conditions signifying that the EMS is either identified as the target radionuclide or as not the target radionuclide, wherein said sequential likelihood ratio is based on a previous sequential likelihood ratio for a previous (n−1) th photon event, the sum of all updated measured PDF estimates produced as output from the set of parallel monoenergy channels, and the sum of all a-priori PDF estimates which are produced in parallel with the updated measured PDF estimates and based on expected amplitude level and interarrival time values of the target radionuclide; and upon determining that one of the two threshold conditions is satisfied, providing notification of the corresponding result, else repeating from the monoenergy selection step for the next (n+1) th photon event of the EMS until one of the two threshold conditions is satisfied.