Computation of the glandular radiation dose in digital tomosynthesis of the breast

Journal Article · Mon Jan 15 04:00:00 EST 2007 · Medical Physics

DOI:https://doi.org/10.1118/1.2400836· OSTI ID:20853914

Sechopoulos, Ioannis; Suryanarayanan, Sankararaman; Vedantham, Srinivasan; D'Orsi, Carl; Karellas, Andrew ^[1]

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1. Emory University School of Medicine, Department of Radiology and Winship Cancer Institute, 1701 Uppergate Drive, Suite 5018, Atlanta, Georgia 30322 (United States) and Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Atlanta, Georgia 30332 (United States)

Tomosynthesis of the breast is currently a topic of intense interest as a logical next step in the evolution of digital mammography. This study reports on the computation of glandular radiation dose in digital tomosynthesis of the breast. Previously, glandular dose estimations in tomosynthesis have been performed using data from studies of radiation dose in conventional planar mammography. This study evaluates, using Monte Carlo methods, the normalized glandular dose (D{sub g}N) to the breast during a tomosynthesis study, and characterizes its dependence on breast size, tissue composition, and x-ray spectrum. The conditions during digital tomosynthesis imaging of the breast were simulated using a computer program based on the Geant4 toolkit. With the use of simulated breasts of varying size, thickness and tissue composition, the D{sub g}N to the breast tissue was computed for varying x-ray spectra and tomosynthesis projection angle. Tomosynthesis projections centered about both the cranio-caudal (CC) and medio-lateral oblique (MLO) views were simulated. For each projection angle, the ratio of the glandular dose for that projection to the glandular dose for the zero degree projection was computed. This ratio was denoted the relative glandular dose (RGD) coefficient, and its variation under different imaging parameters was analyzed. Within mammographic energies, the RGD was found to have a weak dependence on glandular fraction and x-ray spectrum for both views. A substantial dependence on breast size and thickness was found for the MLO view, and to a lesser extent for the CC view. Although RGD values deviate substantially from unity as a function of projection angle, the RGD averaged over all projections in a complete tomosynthesis study varies from 0.91 to 1.01. The RGD results were fit to mathematical functions and the resulting equations are provided.

• OSTI ID: 20853914
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 1 Vol. 34; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
COMPUTER CODES
DOSIMETRY
EVOLUTION
MAMMARY GLANDS
MONTE CARLO METHOD
RADIATION DOSES
THICKNESS
X-RAY SPECTRA