{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8566e96bb7dd4f5ab019047a6db564dbdb27382206cbd6e6992dbc24feb376bf","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["30f5231b62427409c4d77ee23d01ca0b9b43a979c0198d42ee345685205dab00","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"72e2454e8c3f65f4b1bcf4a9afc3885be1f03502be03173399d297c3f90d6b33","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"med.pcct.bin-optimization","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[{"note":"","parent_revision":"30f5231b62427409c4d77ee23d01ca0b9b43a979c0198d42ee345685205dab00","relation":"special_case"}],"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.","posed_since":"2010","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.","problem_ref":null,"references":"","settled_by":"Derivation of the bound plus phantom measurement confirming the predicted variance for optimized thresholds.","status_note":"Information-theoretic treatments exist for idealized detectors; the realistic-response case stays open.","title":"Optimal energy thresholds for material separation","topic_ref":"26d23f25e437e5a24b43745dd4da6507964829094aa1ed73aeaafb9ea3f82278"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"7028ce4a6646b68400ff2d6ab2504b1bfd0d52093f9a54cb83a65fac792c3b66","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"980108fb1d928c44d88c905ea4efe125b3931b3a03bebd180385615e4bc8bd06","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Dy7n48_ekIeE0uTwxCSW0MTMnCh5JF89hEC-AE2SiMvsABsglvr_FZ9rjQ-IaaRXJVDySf-BrtWKxl2ragIMCQ"},"schema":"pubphys.envelope/1"},"record_hash":"7028ce4a6646b68400ff2d6ab2504b1bfd0d52093f9a54cb83a65fac792c3b66","leaf_index":1713}