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Radiation dose estimation using preclinical imaging with I 124 ‐metaiodobenzylguanidine (MIBG) PET
Author(s) -
Lee ChangLae,
Wahnishe Hilla,
Sayre George A.,
Cho HyoMin,
Kim HeeJoung,
HernandezPampaloni Miguel,
Hawkins Randall A.,
Dannoon Shorouk F.,
VanBrocklin Henry F.,
Itsara Melissa,
Weiss William A.,
Yang Xiaodong,
HaasKogan Daphne A.,
Matthay Katherine K.,
Seo Youngho
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3480965
Subject(s) - medicine , nuclear medicine , effective dose (radiation) , dosimetry , positron emission tomography , radiology
Purpose: A pretherapy I124‐metaiodobenzylguanidine (MIBG) positron emission tomography (PET)/computed tomography (CT) provides a potential method to estimate radiation dose to normal organs, as well as tumors prior toI131‐MIBG treatment of neuroblastoma or pheochromocytoma. The aim of this work was to estimate human‐equivalent internal radiation dose ofI124‐MIBG using PET/CT data in a murine xenograft model. Methods: Athymic mice subcutaneously implanted with NB1691 cells that express high levels of human norepinephrine transporter ( n = 4 )were imaged using small animal microPET/CT over 96 h (approximate imaging time points: 0.5, 2, 24, 52, and 96 h) after intravenous administration of 3.07–4.84 MBq ofI124‐MIBG via tail vein. The tumors did not accumulateI124‐MIBG to a detectable level. All four animals were considered as control and organ radiation dosimetry was performed. Volumes of interest were drawn on the coregistered CT images for thyroid, heart, lung, liver, kidney, and bladder, and transferred to PET images to obtain pharmacokinetic data. Based on tabulated organ mass distributions for both mice and adult male human, preclinical pharmacokinetic data were extrapolated to their human‐equivalent values. Radiation dose estimations for different age groups were performed using the OLINDA|EXM software with modified tissue weighting factors in the recent International Commission on Radiological Protection (ICRP) Publication 103. Results: The mean effective dose from I124‐MIBG using weighting factors from ICRP 103 to the adult male was estimated at 0.25 mSv/MBq. In different age groups, effective doses using values from ICRP 103 were estimated as follows: Adult female: 0.34, 15‐yr‐old: 0.39 mSv/MBq, 10‐yr‐old: 0.58 mSv/MBq, 5‐yr‐old: 1.03 mSv/MBq, 1‐yr‐old: 1.92 mSv/MBq, and newborn: 3.75 mSv/MBq. For comparison, the reported effective dose equivalent ofI124‐NaI for adult male (25% thyroid uptake, MIRD Dose Estimate Report No. 5) was 6.5 mSv/MBq. Conclusions: The authors estimated human‐equivalent internal radiation dose of I124‐MIBG using preclinical imaging data. As a reference, the effective dose estimation showed thatI124‐MIBG would deliver less radiation dose thanI124‐NaI, a radiotracer already being used in patients with thyroid cancer.