Skeletal dosimetry in a voxel‐based rat phantom for internal exposures to photons and electrons

Xie, Tianwu; Han, Dongliang; Liu, Yang; Sun, Wenjuan; Liu, Qian

doi:10.1118/1.3380223

Cited by 24 publications

(17 citation statements)

References 37 publications

(28 reference statements)

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“…The methods of image acquisition, segmentation and reconstruction have been described in previous papers. 8,9 In this work, 17 organs, including bladder, brain, esophagus, eyes, heart, intestine, kidney, liver, lung, spleen, stomach, testes, thyroid, mineral bone, red bone marrow, yellow bone marrow, vessel, muscle, and skin were identified and integrated into the updated voxel-based phantom. 18 Meanwhile, all the organs, except vessel, muscle, and skin, were also implemented in the NURBS-based phantom and the stylized phantom, in which the mineral bone, red bone marrow, and yellow bone marrow were integrated into bone for the complicated structure of marrow was difficult to be described by NURBS surfaces or mathematical equations.…”

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confidence: 99%

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

Xie

Zhang

et al. 2010

Applied Physics Letters

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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.

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confidence: 99%

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

Xie

Zhang

et al. 2010

Applied Physics Letters

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“…Several methods have been developed in order to estimate the radiation dose of small animal using monte carlo modelling code [2][3][4]. To our knowledge, this reports the first-in-mouse brain (37 tissues) dosimetry study based on DoseActor tool for geant4 application for tomographic emission simulations (GATE V6.0).…”

Section: Introductionmentioning

confidence: 99%

Mouse Brain Dosimetry in Small Animal CT with GATE Monte Carlo Simulations

et al. 2013

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Abstract-As small animal studies using radiation exposure increase, it becomes more important to estimate accurate dose for the animals in order to explain and control the potential radiation toxicity or treatment efficacy. The purpose of this study was to determine the radiation dose in a realistic mouse brain tissue for dosimetric estimates using geant4 application for tomographic emission simulations (GATE), and to extend its techniques to various small animal CT applications. The realistic mouse phantom (MOBY phantom) is based on high resolution 3D magnetic resonance microscopy data, and the geometry was developed using a segmented C57BL/6 mouse that weighed 33 g. Recently, 37 segmented tissues have been added to voxel-based MOBY brain developed by Johns Hopkins University. A small animal CT system (micro-CT) with Gd 2 O 2 S scintillator was performed using 50 kVp, 0.15 mAs (0.5 second), 360° of rotation, and 400 projections. For validating simulation studies with respect to physical measurements for micro-CT, the measured and simulated airkerma values were compared, and the measured and simulated values measured in the validation CT ion chamber study were total absorbed dose over all measurements to the brain (37 tissues) is 60.2 mGy. Among tissues of brain, the absorbed dose of cerebral_cortex (20.55 mGy) was highest while the one of pineal_gland (0.02 mGy) was lowest. This result can be used in control of brain tissue doses and preclinical targeted radiotherapy experiments as dosimetric database. In addition, in order to calculate accurate absorbed dose of brain tissues, accurate modeling is needed for X-ray spectrum, detector alignment, and uncertainty in elemental composition of simulated materials.

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“…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.…”

Section: Monte Carlo Simulationsmentioning

confidence: 99%

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

Xie

Zaidi

2013

Eur J Nucl Med Mol Imaging

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Purpose Rats are widely used in biomedical research involving molecular imaging and therefore the radiation dose to animals has become a concern. The weight of laboratory animals might change through emaciation or obesity as a result of their use in various research experiments including those investigating different diet types. In this work, we evaluated the effects of changes in body weight induced by emaciation and obesity on the internal radiation dose from common positron-emitting radionuclides. Methods A systematic literature review was performed to determine normal anatomical parameters for adult rats and evaluate how organs change with variations in total body weight. The ROBY rat anatomical model was then modified to produce a normal adult rat, and mildly, moderately and severely emaciated and obese rats. Monte Carlo simulations were performed using MCNPX to estimate absorbed fractions, specific absorbed fractions (SAFs) and S-values for these models using different positron-emitting radionuclides. The results obtained for the different models were compared to corresponding estimates from the normal rat model. Results The SAFs and S-values for most source-target pairs between the various anatomical models were not significantly different, except where the intestine and the total body were considered as source regions. For the intestine, irradiating other organs in the obese model, the SAFs in organs in the anterior region of the splanchnocoele (e.g. kidney, liver and stomach) increased slightly, whereas the SAFs in organs in the posterior region of the splanchnocoele (e.g. bladder and testes) decreased owing to the increase in the distance separating the intestine and posterior abdominal organs because of the rat epididymal fat pad. For the total body, irradiating other organs, the SAFs and S-values were inversely related to body weight. Conclusion The effect of obesity on internal radiation dose is insignificant in most conditions for common positron-emitting radionuclides. Emaciation increases the cross-absorbed dose to organs from surrounding tissues, which might be a notable issue in laboratory animal internal dosimetry.

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Skeletal dosimetry in a voxel‐based rat phantom for internal exposures to photons and electrons

Cited by 24 publications

References 37 publications

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

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

Mouse Brain Dosimetry in Small Animal CT with GATE Monte Carlo Simulations

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

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