Computational Organ Dosimetry of 89 Zr‐Labeled hNd2 for Diagnostic PET Using ICRP Reference Phantoms

This computational study quantifies organ‐specific absorbed doses for diagnostic PET with 89Zr‐labeled hNd2 using ICRP adult male/female reference voxel phantoms and the MIRD/ICRP framework implemented in IDAC‐Dose 2.1, cross‐validated in WinAct 1.0; organ time–activity curves were parameterized for antibody‐type kinetics, integrated to residence times, and converted to absorbed doses using IDAC S‐values. In the female phantom, the heart received the highest absorbed dose (∼5.0 mGy/MBq), followed by the spleen (∼3.8 mGy/MBq) and lung (∼3.4 mGy/MBq); the kidneys and right colon were intermediate (∼2.1 and ∼2.4 mGy/MBq, respectively), while the liver and stomach were ∼1.3–1.6 mGy/MBq, and the left colon was ∼0.5 mGy/MBq. In the male phantom, the heart (∼4.1 mGy/MBq) again dominated, followed by the spleen (∼3.2 mGy/MBq) and lung (∼2.6 mGy/MBq); the kidneys (∼1.7 mGy/MBq) and right colon (∼2.0 mGy/MBq) were intermediate; the liver and stomach ranged ∼1.1–1.2 mGy/MBq, the left colon ∼0.3 mGy/MBq, and the testes ∼1.0 mGy/MBq. These results contextualize organ dose patterns for 89 Zr‐hNd2 PET and, together with the uncertainty analysis and cross‐validation, support protocol optimization (e.g., activity selection and hydration strategies) that balances image quality with radiation safety.