{"artifact_id":"L1-034","layer":"L1","title":"Single-Photon Emission Computed Tomography (SPECT)","domain":"Medical Imaging","sub_domain":"Gamma-camera rotating tomography","physics_fingerprint":{"L_DAG":3.5,"title":"Single-Photon Emission Computed Tomography (SPECT)","domain":"Medical Imaging","carrier":"photon","primitives":["L.gamma_emission","L.collimator","S.scan.angular","L.backproject","int.angular"],"sub_domain":"Gamma-camera rotating tomography","noise_model":"shot_poisson","problem_class":"linear_inverse","solution_space":"3D_activity_concentration","difficulty_delta":5,"integration_axis":"angular","sensing_mechanism":"spect_gamma_camera"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered 3D activity concentration 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 ~= 16); collimator_blur dominates the stability cliff; attenuation_correction_error and the remaining mismatch parameters contribute higher-order bias terms. Photon-shot-noise-limited (poisson counting) sets the irreducible data-fidelity floor, while TV / wavelet-sparsity / deep priors stabilise recovery at the ill-conditioned end of Omega.","secondary":"SSIM"},"size_tiers":{"center_spec":{"omega":{"H":128,"W":128,"Z":64,"SNR_dB":18,"scatter":0.2,"N_angles":64,"patient_motion":0.0,"collimator_blur":0.0,"counts_per_pixel":100,"attenuation_correction_error":0.0},"input_format":"measurement_only","problem_class":"spect","forward_operator":"spect_forward","epsilon_fn_center":"22.0"},"omega_bounds":{"H":64,"W":64,"Z":[16,512],"SNR_dB":[0.0,35.0],"scatter":[0.0,0.5],"N_angles":[8,256],"patient_motion":[0.0,0.3],"collimator_blur":[0.0,0.3],"counts_per_pixel":[1,10000],"attenuation_correction_error":[0.0,0.3]},"epsilon_bounds":{"psnr_db":[5.0,45.0]},"allowed_problem_classes":["spect"],"allowed_omega_dimensions":["H","W","Z","N_angles","counts_per_pixel","SNR_dB","collimator_blur","attenuation_correction_error","scatter","patient_motion","collimator_blur","attenuation_correction_error","scatter","patient_motion"],"allowed_forward_operators":["spect_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":5,"kappa":320,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0xd8fe453230341be5dad2cc48a43e99b867d718d9af5d1016413fcff7adaf0c08","chain_tx_hash":"0xabe2942ee94669f848d13adce3f4cb4f36d37d691190e4c1e0bef96bf1648212","chain_block":41553358}