Ramonaheng, KeamogetsweQebetu, MilaniBanda, KaluziGoorhoo, PryaskaLegodi, KhomotsoMdanda, SiphoSibiya, SandileMzizi, YonwabaNdlovu, HonestKabunda, JosephYang, MengdieShi, KuangyuSathekge, Mike Machaba2026-01-152026-01-152025-11Ramonaheng, K., Qebetu, M., Banda, K. et al. 2025, 'Advances in dosimetry and imaging for 203Pb and 212Pb radiotheranostics', Seminars in Nuclear Medicine, vol. 55, pp. 1011-1031. https://doi.org/10.1053/j.semnuclmed.2025.09.006.0001-2998 (print)10.1053/j.semnuclmed.2025.09.0061558-4623 (online)http://hdl.handle.net/2263/107321Targeted alpha therapy (TAT) with 212Pb is rapidly emerging as a potent modality for cancer treatment due to the high linear energy transfer and short path length of α-particles, which enable precise tumor cell killing while sparing surrounding healthy tissue. Its elementally identical theranostic partner, 203Pb, functions as a γ-emitting surrogate for quantitative SPECT imaging, providing essential information for patient-specific dosimetry and treatment planning. Advances in SPECT imaging, ranging from NaI(Tl)-based dual-head systems to CZT multi-detector gamma cameras, have enhanced spatial resolution, quantitative accuracy, and lesion detectability, enabling rapid patient scanning and improved activity quantification for dosimetry. Clinical dosimetry workflows that integrate serial 203Pb SPECT/CT acquisitions, pharmacokinetic modeling, and image-based activity quantification facilitate reliable generation of time–activity curves and absorbed dose estimates. Organ-level and voxel-based dosimetry, combined with advanced reconstruction and microdosimetric modeling, further refine dose calculations, supporting individualized therapy planning. Collectively, these developments highlight the translational potential of the 203Pb/212Pb theranostic pair. The aim of this review is to provide a comprehensive assessment of 212Pb-TAT, encompassing clinical applications, surrogate imaging with 203Pb, gamma camera performance, dosimetry workflows, and predictive activity quantification, illustrating how these advances collectively enable quantitative, patient-specific, and theranostic-integrated radionuclide therapy.en© 2025 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).DosimetryImaging203Pb212PbRadiotheranosticsTargeted alpha therapy (TAT)Article