{"artifact_id":"L1-158","layer":"L1","title":"SPECT-CT Fusion","domain":"Multimodal Fusion","sub_domain":"Hybrid gamma-camera + X-ray CT","physics_fingerprint":{"L_DAG":3.3,"title":"SPECT-CT Fusion","domain":"Multimodal Fusion","carrier":"photon","primitives":["L.ct_attenuation_map","L.spect_activity_map","L.registration","int.spatial"],"sub_domain":"Hybrid gamma-camera + X-ray CT","noise_model":"gaussian","problem_class":"linear_inverse","solution_space":"3D_fused_activity_anatomy","difficulty_delta":3,"integration_axis":"spatial","sensing_mechanism":"spect_ct_fusion"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered 3D fused activity anatomy is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is moderately conditioned (kappa_eff ~= 13); registration_error dominates the stability cliff; patient_motion and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point.","secondary":"SSIM"},"size_tiers":{"center_spec":{"omega":{"H":128,"W":128,"Z":64,"SNR_dB":20,"patient_motion":0.0,"low_count_SPECT":0.0,"registration_error":0.0,"attenuation_correction_bias":0.0},"input_format":"measurement_only","problem_class":"spect_ct_fusion","forward_operator":"spect_ct_fusion_forward","epsilon_fn_center":"23.0"},"omega_bounds":{"H":64,"W":64,"Z":[16,256],"SNR_dB":[0.0,35.0],"patient_motion":[0.0,10.0],"low_count_SPECT":[0.0,0.5],"registration_error":[0.0,5.0],"attenuation_correction_bias":[0.0,0.3]},"epsilon_bounds":{"psnr_db":[5.0,40.0]},"allowed_problem_classes":["spect_ct_fusion"],"allowed_omega_dimensions":["H","W","Z","registration_error","patient_motion","attenuation_correction_bias","low_count_SPECT","SNR_dB","registration_error","patient_motion","attenuation_correction_bias","low_count_SPECT"],"allowed_forward_operators":["spect_ct_fusion_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":3,"kappa":260,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0x77df44735466efde7f0e91ce90965bbf23c57da5a85797783257eb086bb7e855","chain_tx_hash":"0xcb1d23fc434879276c643072e83951b76ffec261af06ef1323accfb5788f9cb0","chain_block":41554242}