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Portrait of Anders Tingberg. Photo

Anders Tingberg

Associate professor

Portrait of Anders Tingberg. Photo

Dose dependence of mass and microcalcification detection in digital mammography: free response human observer studies.

Author

  • Mark Ruschin
  • Pontus Timberg
  • Magnus Bath
  • Bengt Hemdal
  • Tony Svahn
  • Rob S Saunders
  • Ehsan Samei
  • Ingvar Andersson
  • Sören Mattsson
  • Dev P Chakrabort
  • Anders Tingberg
Show all

Summary, in English

The purpose of this study was to evaluate the effect of dose reduction in digital mammography on the detection of two lesion types-malignant masses and clusters of microcalcifications. Two free-response observer studies were performed-one for each lesion type. Ninety screening images were retrospectively selected; each image was originally acquired under automatic exposure conditions, corresponding to an average glandular dose of 1.3 mGy for a standard breast (50 mm compressed breast thickness with 50% glandularity). For each study, one to three simulated lesions were added to each of 40 images (abnormals) while 50 were kept without lesions (normals). Two levels of simulated system noise were added to the images yielding two new image sets, corresponding to simulated dose levels of 50% and 30% of the original images (100%). The manufacturer's standard display processing was subsequently applied to all images. Four radiologists experienced in mammography evaluated the images by searching for lesions and marking and assigning confidence levels to suspicious regions. The search data were analyzed using jackknife free-response (JAFROC) methodology. For the detection of masses, the mean figure-of-merit (FOM) averaged over all readers was 0.74, 0.71, and 0.68 corresponding to dose levels of 100%, 50%, and 30%, respectively. These values were not statistically different from each other (F = 1.67, p = 0.19) but showed a decreasing trend. In contrast, in the microcalcification study the mean FOM was 0.93, 0.67, and 0.38 for the same dose levels and these values were all significantly different from each other (F = 109.84, p < 0.000 1). The results indicate that lowering the present dose level by a factor of two compromised the detection of microcalcifications but had a weaker effect on mass detection.

Department/s

  • Medical Radiation Physics, Malmö
  • Radiology Diagnostics, Malmö

Publishing year

2007

Language

English

Pages

400-407

Publication/Series

Medical Physics

Volume

34

Issue

2

Document type

Journal article

Publisher

American Association of Physicists in Medicine

Topic

  • Biophysics

Keywords

  • observer performance
  • free response
  • dose reduction
  • Digital mammography

Status

Published

Research group

  • Medical Radiation Physics, Malmö
  • Radiology Diagnostics, Malmö

ISBN/ISSN/Other

  • ISSN: 0094-2405