Comparison of absorbed fractions of electrons and photons using three kinds of computational phantoms of rat

Abstract

Rats have been widely used in radiopharmaceutics researches, making it reasonable to develop fine structured computational models for rat internal dose investigation. In this work, we developed three existing types of computational phantoms based on the same data set of rat, simulated photon and electron particles transport using Monte Carlo method and calculated absorbed fractions for organs. We further compared the dose discrepancies of these three types of phantoms in internal dosimetry and found the stylized phantom might cause an underestimation of the self-absorbed S-factors. The developed phantoms will contribute to the application of computational phantoms in dosimetry studies.

Effect of emaciation and obesity on small-animal internal radiation dosimetry for positron-emitting radionuclides

“…Comparisons with the results of Stabin et al [11], Peixoto et al [17] and Xie et al [7] are also given. Consistent tendencies of curves are presented and self-absorbed fractions of different rat models are close together.…”

“…The absorbed fractions, reflecting the proportion of energy released in source organs and deposited in the target organ, were calculated for all organs. These estimates were then compared with similar quantities calculated for the seven developed rat models as well as computational rat models developed by Stabin et al [11], Peixoto et al [17] and Xie et al [7,40]. In addition, the SAFs, reflecting the mean absorbed fraction in a target organ, were also calculated based on the absorbed fractions.…”

“…In human dose calculations, cross-absorbed SAFs for organs are commonly negligible [45] since the range of low-energy electrons is smaller than the dimensions of most human organs , Peixoto et al [17] and Xie et al [7] are also shown [47]. However, given that the body dimensions of rats are much smaller, it is necessary to evaluate the cross-absorbed SAFs in rat internal radiation dosimetry.…”

“…Further improvements led to finer stylized small-animal models including rat [6,7] and mouse models containing more internal organs and even realistic tumour models [8][9][10]. Likewise, various voxel-based smallanimal models have been developed by different groups for radiation dosimetry research using different specimens [11][12][13][14][15][16][17][18][19].…”

Comparison of Photon and Electron Absorbed Fractions in Voxel-Based and Simplified Phantoms for Small Animals

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17] The dose evaluations were done using the point-kernel [4][5][6] and the Monte Carlo methods [6][7][8][9][10][11][12][13][14][15][16][17] in several mathematical phantoms such as stylized [4][5][6][7] and voxel-based phantoms. [8][9][10][11][12][13][14][15][16][17] The stylized phantoms are assumed to be simple shapes, such as ellipsoids, cylinders or spheroids as organs of the animals. The voxel-based phantoms were used to improve the accuracy of dosimetry since they have a more realistic anatomy and were developed from computed tomography (CT) and magnetic resonance imaging (MRI) data.…”