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Title: Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom

Abstract

The purpose of this work was to calculate radiation dose and its organ distribution in a realistic mouse phantom from micro-computed tomography (microCT) imaging protocols. CT dose was calculated using GATE and a voxelized, realistic phantom. The x-ray photon energy spectra used in simulations were precalculated with GATE and validated against previously published data. The number of photons required per simulated experiments was determined by direct exposure measurements. Simulated experiments were performed for three types of beams and two types of mouse beds. Dose-volume histograms and dose percentiles were calculated for each organ. For a typical microCT screening examination with a reconstruction voxel size of 200 {mu}m, the average whole body dose varied from 80 mGy (at 80 kVp) to 160 mGy (at 50 kVp), showing a strong dependence on beam hardness. The average dose to the bone marrow is close to the soft tissue average. However, due to dose nonuniformity and higher radiation sensitivity, 5% of the marrow would receive an effective dose about four times higher than the average. If CT is performed longitudinally, a significant radiation dose can be given. The total absorbed radiation dose is a function of milliamperes-second, beam hardness, and desired image quality (resolution,more » noise and contrast). To reduce dose, it would be advisable to use the hardest beam possible while maintaining an acceptable contrast in the image.« less

Authors:
; ;  [1]
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  1. Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California School of Medicine, 700 Westwood Boulevard, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
20774974
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 33; Journal Issue: 1; Other Information: DOI: 10.1118/1.2148333; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BONE MARROW; COMPUTERIZED SIMULATION; COMPUTERIZED TOMOGRAPHY; ENERGY SPECTRA; IMAGES; MICE; MONTE CARLO METHOD; PHANTOMS; PHOTONS; RADIATION DOSES; SENSITIVITY

Citation Formats

Taschereau, Richard, Chow, Patrick L., and Chatziioannou, Arion F. Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom. United States: N. p., 2006. Web. doi:10.1118/1.2148333.
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Taschereau, Richard, Chow, Patrick L., & Chatziioannou, Arion F. Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom. United States. doi:10.1118/1.2148333.
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Taschereau, Richard, Chow, Patrick L., and Chatziioannou, Arion F. Sun . "Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom". United States. doi:10.1118/1.2148333.
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@article{osti_20774974,
title = {Monte Carlo simulations of dose from microCT imaging procedures in a realistic mouse phantom},
author = {Taschereau, Richard and Chow, Patrick L. and Chatziioannou, Arion F.},
abstractNote = {The purpose of this work was to calculate radiation dose and its organ distribution in a realistic mouse phantom from micro-computed tomography (microCT) imaging protocols. CT dose was calculated using GATE and a voxelized, realistic phantom. The x-ray photon energy spectra used in simulations were precalculated with GATE and validated against previously published data. The number of photons required per simulated experiments was determined by direct exposure measurements. Simulated experiments were performed for three types of beams and two types of mouse beds. Dose-volume histograms and dose percentiles were calculated for each organ. For a typical microCT screening examination with a reconstruction voxel size of 200 {mu}m, the average whole body dose varied from 80 mGy (at 80 kVp) to 160 mGy (at 50 kVp), showing a strong dependence on beam hardness. The average dose to the bone marrow is close to the soft tissue average. However, due to dose nonuniformity and higher radiation sensitivity, 5% of the marrow would receive an effective dose about four times higher than the average. If CT is performed longitudinally, a significant radiation dose can be given. The total absorbed radiation dose is a function of milliamperes-second, beam hardness, and desired image quality (resolution, noise and contrast). To reduce dose, it would be advisable to use the hardest beam possible while maintaining an acceptable contrast in the image.},
doi = {10.1118/1.2148333},
journal = {Medical Physics},
number = 1,
volume = 33,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
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Journal Article:
DOI:  10.1118/1.2148333
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  • ; - Medical Physics
    The purpose of this study was to calculate internal absorbed dose distribution in mice from preclinical small animal PET imaging procedures with fluorine-18 labeled compounds ({sup 18}FDG, {sup 18}FLT, and fluoride ion). The GATE Monte Carlo software and a realistic, voxel-based mouse phantom that included a subcutaneous tumor were used to perform simulations. Discretized time-activity curves obtained from dynamic in vivo studies with each of the compounds were used to set the activity concentration in the simulations. For {sup 18}FDG, a realistic range of uptake ratios was considered for the heart and tumor. For each simulated time frame, the biodistributionmore » of the radionuclide in the phantom was considered constant, and a sufficient number of decays were simulated to achieve low statistical uncertainty. Absorbed dose, which was scaled to take into account radioactive decay, integration with time, and changes in biological distribution was reported in mGy per MBq of administered activity for several organs and uptake scenarios. The mean absorbed dose ranged from a few mGy/MBq to hundreds of mGy/MBq. Major organs receive an absorbed dose in a range for which biological effects have been reported. The effects on a given investigation are hard to predict; however, investigators should be aware of potential perturbations especially when the studied organ receives high absorbed dose and when longitudinal imaging protocols are considered.« less

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