000K utf8 1100 2024$c2024-01-03 1500 eng 2050 urn:nbn:de:hbz:465-20250114-122734-4 2051 10.1186/s40658-023-00604-0 3000 Moraitis, Alexandros 3010 Bockisch, Andreas 3010 Fendler, Wolfgang Peter 3010 Fragoso Costa, Pedro 3010 Herrmann, Ken 3010 Jentzen, Walter 3010 Kersting, David 3010 Pöppel, Thorsten Dirk 3010 Reiter, Gloria 3010 Schmitz, Jochen 3010 Weber, Manuel 4000 Biodistribution and radiation dosimetry of ¹²⁴I-mIBG in adult patients with neural crest tumours and extrapolation to paediatric models [Moraitis, Alexandros] 4209 Aim: Positron emission tomography (PET) using 124I-mIBG has been established for imaging and pretherapeutic dosimetry. Here, we report the first systematic analysis of the biodistribution and radiation dosimetry of 124I-mIBG in patients with neural crest tumours and project the results to paediatric patient models. Methods: Adult patients with neural crest tumours who underwent sequential 124I-mIBG PET were included in this retrospective single-center analysis. PET data were acquired 4, 24, 48, and/or 120 h after administration of a mean of 43 MBq 124I-mIBG. Whole-body counting and blood sampling were performed at 2, 4, 24, 48 and 120 h after administration. Absorbed organ dose and effective dose coefficients were estimated in OLINDA/EXM 2.2 according to the MIRD formalism. Extrapolation to paediatric models was performed based on mass-fraction scaling of the organ-specific residence times. Biodistribution data for adults were also projected to 123I-mIBG and 131I-mIBG. Results: Twenty-one patients (11 females, 10 males) were evaluated. For adults, the organs exposed to the highest dose per unit administered activity were urinary bladder (1.54 ± 0.40 mGy/MBq), salivary glands (0.77 ± 0.28 mGy/MBq) and liver (0.65 ± 0.22 mGy/MBq). Mean effective dose coefficient for adults was 0.25 ± 0.04 mSv/MBq (male: 0.24 ± 0.03 mSv/MBq, female: 0.26 ± 0.06 mSv/MBq), and increased gradually to 0.29, 0.44, 0.69, 1.21, and 2.94 mSv/MBq for the 15-, 10-, 5-, 1-years-old, and newborn paediatric reference patients. Projected mean effective dose coefficients for 123I-mIBG and 131I-mIBG for adults were 0.014 ± 0.002 mSv/MBq and 0.18 ± 0.04 mSv/MBq, respectively. Conclusion: PET-based derived radiation dosimetry data for 124I-mIBG from this study agreed well with historical projected data from ICRP 53. The effective dose coefficients presented here may aid in guidance for establishing weight-based activity administration protocols. 4950 https://doi.org/10.1186/s40658-023-00604-0$xR$3Volltext$534 4950 https://nbn-resolving.org/urn:nbn:de:hbz:465-20250114-122734-4$xR$3Volltext$534 4961 https://duepublico2.uni-due.de/receive/duepublico_mods_00082282 5051 610 5550 124I-mIBG 5550 Dosimetry 5550 Effective dose 5550 Neural crest tumour 5550 PET