{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"bf490893265d3b4e0cafc74c597aeb571514d87736babba628fe15a132372170","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"40d01e20fbc34cb0285081af04eebc335230d8dbe0dd7963d5f5020e70c3b644","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"med.radionuclide-therapy.quantitative-imaging","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"To compute the dose, the drug must be seen and counted inside the body, but alpha-emitting drugs give off very few detectable photons.","posed_since":"2015","precise":"Achieve activity quantification to better than 10 percent for therapeutic nuclides with sparse or complex photon emission, notably Ac-225 at administered activities of order 2.7 microCi per kg (about 0.2 mCi per patient), imaged through the daughter gamma lines at 218 keV (Fr-221) and 440 keV (Bi-213), and Pb-212 at 239 keV, including scatter, collimator septal penetration and partial-volume correction. An answer is a calibrated imaging and reconstruction protocol with measured accuracy.","problem_ref":null,"references":"","settled_by":"Phantom and patient measurements with independent activity ground truth demonstrating the stated accuracy.","status_note":"","title":"Quantitative imaging of low-yield therapeutic emitters","topic_ref":"6c8bec8f6507d1401333ef1f0d3b8af96544abd2d55b8980500938f7c5f01fb2"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"4335bf823ded2c82aa8930b9fa55f5cdc2e7341ff6b0889b4379e0d330f7aa0f","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"9959d59abc5481735e470d301e550d2796ef2e9627ea939492b3928bbaa83251","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"4BpsOH4jnRyEYHZfCL9GZmmpVWIZgT-AZg4d_GKy87sQY7nSH2q7UylwjQdDHLW_HXphQq9mT3v4C7TNZ0SsAQ"},"schema":"pubphys.envelope/1"},"record_hash":"4335bf823ded2c82aa8930b9fa55f5cdc2e7341ff6b0889b4379e0d330f7aa0f","leaf_index":1723}