skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The UF series of tomographic computational phantoms of pediatric patients

Abstract

Two classes of anthropomorphic computational phantoms exist for use in Monte Carlo radiation transport simulations: tomographic voxel phantoms based upon three-dimensional (3D) medical images, and stylized mathematical phantoms based upon 3D surface equations for internal organ definition. Tomographic phantoms have shown distinct advantages over the stylized phantoms regarding their similarity to real human anatomy. However, while a number of adult tomographic phantoms have been developed since the early 1990s, very few pediatric tomographic phantoms are presently available to support dosimetry in pediatric diagnostic and therapy examinations. As part of a larger effort to construct a series of tomographic phantoms of pediatric patients, five phantoms of different ages (9-month male, 4-year female, 8-year female, 11-year male, and 14-year male) have been constructed from computed tomography (CT) image data of live patients using an IDL-based image segmentation tool. Lungs, bones, and adipose tissue were automatically segmented through use of window leveling of the original CT numbers. Additional organs were segmented either semiautomatically or manually with the aid of both anatomical knowledge and available image-processing techniques. Layers of skin were created by adding voxels along the exterior contour of the bodies. The phantoms were created from fused images taken from head and chest-abdomen-pelvismore » CT exams of the same individuals (9-month and 4-year phantoms) or of two different individuals of the same sex and similar age (8-year, 11-year, and 14-year phantoms). For each model, the resolution and slice positions of the image sets were adjusted based upon their anatomical coverage and then fused to a single head-torso image set. The resolutions of the phantoms for the 9-month, 4-year, 8-year, 11-year, and 14-year are 0.43x0.43x3.0 mm, 0.45x0.45x5.0 mm, 0.58x0.58x6.0 mm, 0.47x0.47x6.00 mm, and 0.625x0.625x6.0 mm, respectively. While organ masses can be matched to reference values in both stylized and tomographic phantoms, side-by-side comparisons of organ doses in both phantom classes indicate that organ shape and positioning are equally important parameters to consider in accurate determinations of organ absorbed dose from external photon irradiation. Preliminary studies of external photon irradiation of the 11-year phantom indicate significant departures of organ dose coefficients from that predicted by the existing stylized phantom series. Notable differences between pediatric stylized and tomographic phantoms include anterior-posterior (AP) and right lateral (RLAT) irradiation of the stomach wall, left lateral (LLAT) and right lateral (RLAT) irradiation of the thyroid, and AP and posterior-anterior (PA) irradiation of the urinary bladder.« less

Authors:
; ; ;  [1];  [2];  [2];  [2]
  1. Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20726854
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 32; Journal Issue: 12; Other Information: DOI: 10.1118/1.2107067; (c) 2005 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; ADIPOSE TISSUE; BLADDER; COMPUTERIZED TOMOGRAPHY; HEAD; IMAGE PROCESSING; IMAGES; IRRADIATION; LUNGS; MONTE CARLO METHOD; PATIENTS; PHANTOMS; PHOTONS; RADIATION DOSES; RADIOTHERAPY; SKELETON; SKIN; STOMACH; THYROID

Citation Formats

Lee, Choonik, Williams, Jonathan L., Lee, Choonsik, Bolch, Wesley E., Department of Radiology, University of Florida, Gainesville, Florida 32610, Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611, and Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611. The UF series of tomographic computational phantoms of pediatric patients. United States: N. p., 2005. Web. doi:10.1118/1.2107067.
Lee, Choonik, Williams, Jonathan L., Lee, Choonsik, Bolch, Wesley E., Department of Radiology, University of Florida, Gainesville, Florida 32610, Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611, & Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611. The UF series of tomographic computational phantoms of pediatric patients. United States. doi:10.1118/1.2107067.
Lee, Choonik, Williams, Jonathan L., Lee, Choonsik, Bolch, Wesley E., Department of Radiology, University of Florida, Gainesville, Florida 32610, Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611, and Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611. Thu . "The UF series of tomographic computational phantoms of pediatric patients". United States. doi:10.1118/1.2107067.
@article{osti_20726854,
title = {The UF series of tomographic computational phantoms of pediatric patients},
author = {Lee, Choonik and Williams, Jonathan L. and Lee, Choonsik and Bolch, Wesley E. and Department of Radiology, University of Florida, Gainesville, Florida 32610 and Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 and Departments of Nuclear and Radiological and Biomedical Engineering, University of Florida, Gainesville, Florida 32611},
abstractNote = {Two classes of anthropomorphic computational phantoms exist for use in Monte Carlo radiation transport simulations: tomographic voxel phantoms based upon three-dimensional (3D) medical images, and stylized mathematical phantoms based upon 3D surface equations for internal organ definition. Tomographic phantoms have shown distinct advantages over the stylized phantoms regarding their similarity to real human anatomy. However, while a number of adult tomographic phantoms have been developed since the early 1990s, very few pediatric tomographic phantoms are presently available to support dosimetry in pediatric diagnostic and therapy examinations. As part of a larger effort to construct a series of tomographic phantoms of pediatric patients, five phantoms of different ages (9-month male, 4-year female, 8-year female, 11-year male, and 14-year male) have been constructed from computed tomography (CT) image data of live patients using an IDL-based image segmentation tool. Lungs, bones, and adipose tissue were automatically segmented through use of window leveling of the original CT numbers. Additional organs were segmented either semiautomatically or manually with the aid of both anatomical knowledge and available image-processing techniques. Layers of skin were created by adding voxels along the exterior contour of the bodies. The phantoms were created from fused images taken from head and chest-abdomen-pelvis CT exams of the same individuals (9-month and 4-year phantoms) or of two different individuals of the same sex and similar age (8-year, 11-year, and 14-year phantoms). For each model, the resolution and slice positions of the image sets were adjusted based upon their anatomical coverage and then fused to a single head-torso image set. The resolutions of the phantoms for the 9-month, 4-year, 8-year, 11-year, and 14-year are 0.43x0.43x3.0 mm, 0.45x0.45x5.0 mm, 0.58x0.58x6.0 mm, 0.47x0.47x6.00 mm, and 0.625x0.625x6.0 mm, respectively. While organ masses can be matched to reference values in both stylized and tomographic phantoms, side-by-side comparisons of organ doses in both phantom classes indicate that organ shape and positioning are equally important parameters to consider in accurate determinations of organ absorbed dose from external photon irradiation. Preliminary studies of external photon irradiation of the 11-year phantom indicate significant departures of organ dose coefficients from that predicted by the existing stylized phantom series. Notable differences between pediatric stylized and tomographic phantoms include anterior-posterior (AP) and right lateral (RLAT) irradiation of the stomach wall, left lateral (LLAT) and right lateral (RLAT) irradiation of the thyroid, and AP and posterior-anterior (PA) irradiation of the urinary bladder.},
doi = {10.1118/1.2107067},
journal = {Medical Physics},
number = 12,
volume = 32,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}