{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"ee7f8b9b7799f332fa3b2c4a678f8dc204a1ff9aec97d6ca689aec5692a48470","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"5310683a56282d7592eb58d44f16112e17da4b7d749eeee7ba74c9f76145b307","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"med.pet.reconstruction-free","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"If the timing becomes precise enough, each detected pair marks its own point in space, so the image can be built without reconstruction. The timing and sampling requirements for that are not worked out.","posed_since":"2017","precise":"Establish the coincidence time resolution, detector solid-angle coverage and count statistics at which direct event-by-event image formation matches or beats iterative tomographic reconstruction in task-based detectability for lesions of 5 to 10 mm. An answer is the threshold condition, stated in ps and counts, with the comparison metric.","problem_ref":null,"references":"","settled_by":"Simulation and phantom studies comparing direct and reconstructed images across timing resolution at fixed counts.","status_note":"","title":"Imaging without tomographic reconstruction","topic_ref":"82c46a639f6fd1f2c6c4e5f93efaf610a76f3cc0784379dd43df49391264c57d"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5259b0c1b2fe39714042aa5b9c631928ca17fead6bc3335c75c5f432a720ce24","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"692700c40fe85af8e7ca257bde232909391196df7266310d38261f60edfe7a36","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"DK5Wj2J03f6xGMgSFc48hXAnceClG-fsR23R9K7qpR7_NXIV-2m8iZipYxv0l1bClEDp58bHAGRMTMZbAAxYBg"},"schema":"pubphys.envelope/1"},"record_hash":"5259b0c1b2fe39714042aa5b9c631928ca17fead6bc3335c75c5f432a720ce24","leaf_index":1715}