Dual-energy digital mammography for calcification imaging: Theory and implementation

S. Cheenu Kappadath, Chris Shaw, Chao Jen Lai, Xinming Liu, Gary Whitman

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations

Abstract

Small microcalcifications essential to the early detection of breast cancer may be obscured by overlapping tissue structures. Dual-energy digital mammography (DEDM), where separate low-and high-energy images are acquired and synthesized to cancel the tissue structures, may improve the ability to detect and visualize microcalcifications. The investigation of DEDM began with a signal-to noise ratio analysis to estimate and relate the noise level in the dual-energy calcification signals to the x-ray spectra, microcalcification size, tissue composition and breast thickness. We investigated various inverse-mapping functions, both linear and non-linear, to estimate the calcification thickness from low- and high-energy measurements. Transmission (calibration) measurements made at two different kVp values for variable aluminum thickness (to simulate calcifications) and variable glandular-tissue ratio for a fixed total tissue thickness were used to determine the coefficients of the inverse-mapping functions by a least-squares analysis. We implemented and evaluated the DEDM technique under narrow-beam geometry. Phantoms, used in the evaluation, were constructed by placing different aluminum strips over breast-tissue-equivalent materials of different compositions. The resulting phantom images consisted of four distinct regions, each with a different combination of aluminum thickness and tissue composition. DEDM with non-linear inverse-mapping functions could successfully cancel the contrast of the tissue-structure background to better visualize the overlapping aluminum strip. We are currently in the process of translating our DEDM techniques into full-field imaging. We have designed special phantoms with variable glandular ratios and variable calcification thicknesses for evaluation of the full-field dual-energy calcification images.

Original languageEnglish (US)
Pages (from-to)751-760
Number of pages10
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5368
Issue number2
DOIs
StatePublished - 2004
EventMedical Imaging 2004: Physics of Medical Imaging - San Diego, CA, United States
Duration: Feb 15 2004Feb 17 2004

Keywords

  • Calcifications
  • Digital imaging
  • Dual-energy
  • Inverse-mapping
  • Mammography

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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