Photon and electron absorbed fractions calculated from a new tomographic rat model

Abstract

This paper describes the development of a tomographic model of a rat developed using CT images of an adult male Wistar rat for radiation transport studies. It also presents calculations of absorbed fractions (AFs) under internal photon and electron sources using this rat model and the Monte Carlo code MCNP. All data related to the developed phantom were made available for the scientific community as well as the MCNP inputs prepared for AF calculations in that phantom and also all estimated AF values, which could be used to obtain absorbed dose estimates--following the MIRD methodology--in rats similar in size to the presently developed model. Comparison between the rat model developed in this study and that published by Stabin et al (2006 J. Nucl. Med. 47 655) for a 248 g Sprague-Dawley rat, as well as between the estimated AF values for both models, has been presented.

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.…”

“…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]. More recently, computational models of laboratory animals based on non-uniform rational B-spline surfaces (NURBS) have become available [20].…”

Assessment of radiation exposure of murine rodents at the EURT territories

“…for humans, the calculations of dose coefficients relating the intake of radionuclides and the equivalent dose in organs are made using the human voxel models. Recently, a number of animal voxel phantoms, particularly mice voxel phantoms, were developed [23][24][25][26][27].…”

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.…”