Evaluation of self-absorbed doses for the kidneys of a voxel mouse

Kidney dosimetry in mice is of considerable significance in preclinical studies of new radiopharmaceuticals. There has been a gradual accumulation of kidney dosimetry data in mouse studies. However, a comprehensive understanding of the kidney dosimetry is still lacking. To conduct reliable kidney dosimetry, there exists a need to evaluate self-absorbed fractions (self-AFs) for sophisticated models of the kidneys. In the present study, self-AFs for photons and electrons in the kidneys of a voxel mouse were evaluated using Monte Carlo simulations. The sources were assumed to be monoenergetic in the energy range 10 keV-4 MeV, and be uniformly distributed in the kidneys. The self-AFs for the kidneys of the voxel mouse were compared with those for voxel humans. In addition, self-S values (μGy/MBq·s) for ¹⁸F and ⁹⁰Y of potential interest in the kidney dosimetry were assessed using the self-AFs. It was found that the photon self-AFs for the voxel mouse are significantly smaller than those for the voxel humans and that the electron self-AFs for the voxel mouse are consistent with those for the voxel humans in the energy range 10 - 100 keV, followed by a sharp fall. The self-S values for the voxel mouse were found to be much larger than those for the voxel humans. (author)