Organ biodistribution of Germanium-68 in rat in the presence and absence of [68Ga]Ga-DOTA-TOC for the extrapolation to the human organ and whole-body radiation dosimetry

American Journal of Nuclear Medicine and Molecular Imaging

Gunnar Antoni¹  Sergio Estrada¹  Jens Sörensen¹  Irina Velikyan¹ 

关键词: Positron emission tomography;    68Ga;    68Ge;    dosimetry;    68Ge/68Ga generator;   

DOI  :  

学科分类：过敏症与临床免疫学

来源: e-Century Publishing Corporation

【 摘 要 】

Positron Emission Tomography (PET) and in particular gallium-68 (⁶⁸Ga) applications are growing exponentially worldwide contributing to the expansion of nuclear medicine and personalized management of patients. The significance of ⁶⁸Ga utility is reflected in the implementation of European Pharmacopoeia monographs. However, there is one crucial point in the monographs that might limit the use of the generators and consequently expansion of ⁶⁸Ga applications and that is the limit of 0.001% of Germanium-68 (⁶⁸Ge(IV)) radioactivity content in a radiopharmaceutical. We have investigated the organ distribution of ⁶⁸Ge(IV) in rat and estimated human dosimetry parameters in order to provide experimental evidence for the determination and justification of the ⁶⁸Ge(IV) limit. Male and female rats were injected in the tail vein with formulated [⁶⁸Ge]GeCl₄ in the absence or presence of [⁶⁸Ga]Ga-DOTA-TOC. The tissue radioactivity distribution data was extrapolated for the estimation of human organ equivalent doses and total effective dose using Organ Level Internal Dose Assessment Code software (OLINDA/EXM). ⁶⁸Ge(IV) was evenly distributed among the rat organs and fast renal excretion prevailed. Human organ equivalent dose and total effective dose estimates indicated that the kidneys were the dose-limiting organs (185±54 μSv/MBq for female and 171±38 μSv/MBq for male) and the total effective dose was 15.5±0.1 and 10.7±1.2 μSv/MBq, respectively for female and male. The results of this dosimetry study conclude that the ⁶⁸Ge(IV) limit currently recommended by monographs could be increased considerably (>100 times) without exposing the patient to harm given the small absorbed doses to normal organs and fast excretion.

【 授权许可】

Unknown