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Portrait of Anders Tingberg. Photo

Anders Tingberg

Associate professor

Portrait of Anders Tingberg. Photo

Shape determination of microcalcifications in simulated digital mammography images with varying pixel size

Author

  • Mark Ruschin
  • M Bath
  • Bengt Hemdal
  • Anders Tingberg

Summary, in English

The purpose of this work was to study how the pixel size of digital detectors can affect shape determination of microcalcifications in mammography. Screen-film mammograms containing microcalcifications clinically proven to be indicative of malignancy were digitised at 100 lines/mm using a high-resolution Tango drum scanner. Forty microcalcifications were selected to cover an appropriate range of sizes, shapes and contrasts typically found of malignant cases. Based on the measured MTF and NPS of the combined screen-film and scanner system, these digitised images were filtered to simulate images acquired with a square sampling pixel size of 10 μm × 10 μm and a fill factor of one. To simulate images acquired with larger pixel sizes, these finely sampled images were re-binned to yield a range of effective pixel sizes from 20 μm up to 140 μm. An alternative forced-choice (AFC) observer experiment was conducted with eleven observers for this set of digitised microcalcifications to determine how pixel size affects the ability to discriminate shape. It was found that observer score increased with decreasing pixel size down to 60 μm (p<0.01), at which point no significant advantage was obtained by using smaller pixel sizes due to the excessive relative noise-per-pixel. The relative gain in shape discrimination ability at smaller pixel sizes was larger for microcalcifications that were smaller than 500 μm and circular

Department/s

  • Medical Radiation Physics, Malmö

Publishing year

2005

Language

English

Pages

288-299

Publication/Series

Proceedings of the SPIE - The International Society for Optical Engineering

Volume

5749

Issue

1

Document type

Conference paper

Publisher

SPIE

Topic

  • Radiology, Nuclear Medicine and Medical Imaging

Keywords

  • alternative forced-choice observer
  • fill factor
  • digitised image filtering
  • MTF
  • high-resolution Tango drum scanner
  • screen-film mammograms
  • digital detectors
  • pixel size
  • simulated digital mammography images
  • shape determination
  • microcalcifications
  • relative noise-per-pixel
  • shape discrimination
  • relative gain
  • image restoration
  • 20 to 140 micron

Conference name

Medical Imaging 2005: Image Perception, Observer Performance, and Technology Assessment

Conference date

2005-02-15

Conference place

San Diego, CA, United States

Status

Published

Research group

  • Medical Radiation Physics, Malmö

ISBN/ISSN/Other

  • ISSN: 1996-756X
  • ISSN: 0277-786X
  • CODEN: PSISDG