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Title: An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam

Abstract

X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane.more » The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.« less

Authors:
; ;  [1];  [2];  [3];  [4]
  1. Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba, R3A 1R9 (Canada)
  2. (Canada)
  3. (Canada) and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada)
  4. (Canada) and Department of Electrical and Computer Engineering, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada)
Publication Date:
OSTI Identifier:
20853917
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 34; Journal Issue: 1; Other Information: DOI: 10.1118/1.2400835; (c) 2007 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; ALGORITHMS; BIOMEDICAL RADIOGRAPHY; COMPTON EFFECT; COMPUTERIZED TOMOGRAPHY; ELECTRON DENSITY; IMAGE PROCESSING; IMAGES; ITERATIVE METHODS; MAMMARY GLANDS; MONTE CARLO METHOD; NEOPLASMS; PHANTOMS; SENSITIVITY; X RADIATION

Citation Formats

Van Uytven, Eric, Pistorius, Stephen, Gordon, Richard, Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9, and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9. An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam. United States: N. p., 2007. Web. doi:10.1118/1.2400835.
Van Uytven, Eric, Pistorius, Stephen, Gordon, Richard, Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9, & Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9. An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam. United States. doi:10.1118/1.2400835.
Van Uytven, Eric, Pistorius, Stephen, Gordon, Richard, Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9, and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9. Mon . "An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam". United States. doi:10.1118/1.2400835.
@article{osti_20853917,
title = {An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam},
author = {Van Uytven, Eric and Pistorius, Stephen and Gordon, Richard and Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 and Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9 and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9},
abstractNote = {X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane. The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.},
doi = {10.1118/1.2400835},
journal = {Medical Physics},
number = 1,
volume = 34,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}