Revision 1

Accepted · first revision · record

Title: Optimal energy thresholds for material separation
Plain: The detector sorts photons into a few energy bins. Where to place the bin edges for the best material separation at the lowest dose is unsolved in general.
Precise: Determine the energy threshold set that minimizes the variance of material-decomposition estimates for a given task, tube spectrum, patient thickness and dose, including the detector response with charge sharing and pileup. Compare against the Cramer-Rao bound (the minimum variance any unbiased estimator can reach) achievable with full spectral information. An answer is an optimization rule plus the efficiency loss from using 2 to 8 bins.
Settled by: Derivation of the bound plus phantom measurement confirming the predicted variance for optimized thresholds.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: partially-resolved
Status note: Information-theoretic treatments exist for idealized detectors; the realistic-response case stays open.
Posed since: 2010