A method is disclosed that includes decomposing, with a decomposer, agent-based time series projection data for an object or a subject into at least an agent based component. A projection data decomposer includes a time series decomposer that determines agent-based projection data based on agent-based time series projection data based on at least two energy dependent components. A computer readable storage medium containing instructions which, when executed by a computer, cause the computer to perform the act of determining an agent-based component of agent-based time series projection data utilizing at least two components of the agent-based time series projection is provided.