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Proceedings Paper

Patient specific computerized phantoms to estimate dose in pediatric CT
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Paper Abstract

We create a series of detailed computerized phantoms to estimate patient organ and effective dose in pediatric CT and investigate techniques for efficiently creating patient-specific phantoms based on imaging data. The initial anatomy of each phantom was previously developed based on manual segmentation of pediatric CT data. Each phantom was extended to include a more detailed anatomy based on morphing an existing adult phantom in our laboratory to match the framework (based on segmentation) defined for the target pediatric model. By morphing a template anatomy to match the patient data in the LDDMM framework, it was possible to create a patient specific phantom with many anatomical structures, some not visible in the CT data. The adult models contain thousands of defined structures that were transformed to define them in each pediatric anatomy. The accuracy of this method, under different conditions, was tested using a known voxelized phantom as the target. Errors were measured in terms of a distance map between the predicted organ surfaces and the known ones. We also compared calculated dose measurements to see the effect of different magnitudes of errors in morphing. Despite some variations in organ geometry, dose measurements from morphing predictions were found to agree with those calculated from the voxelized phantom thus demonstrating the feasibility of our methods.

Paper Details

Date Published: 27 February 2009
PDF: 9 pages
Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 72580H (27 February 2009); doi: 10.1117/12.813517
Show Author Affiliations
W. P. Segars, Duke Univ. (United States)
G. Sturgeon, Duke Univ. (United States)
Univ. of North Carolina at Chapel Hill (United States)
X. Li, Duke Univ. (United States)
L. Cheng, The Johns Hopkins Univ. (United States)
C. Ceritoglu, The Johns Hopkins Univ. (United States)
J. T. Ratnanather, The Johns Hopkins Univ. (United States)
M. I. Miller, The Johns Hopkins Univ. (United States)
B. M. W. Tsui, The Johns Hopkins Univ. (United States)
D. Frush, Duke Univ. (United States)
E. Samei, Duke Univ. (United States)

Published in SPIE Proceedings Vol. 7258:
Medical Imaging 2009: Physics of Medical Imaging
Ehsan Samei; Jiang Hsieh, Editor(s)

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