A case study on the impact of a reduction in MTF on test object detectability score in mammography

K. T. Wigati, H. Bosmans, L. Cockmartin, G. Zhang, L. Vancoillie, D. Petrov, D. A.N. Vandenbroucke, D. S. Soejoko, N. W. Marshall

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This work examined the impact of the presampling Modulation Transfer Function (MTF) on detectability of lesion-like targets in digital mammography. Two needle CR plates (CR1 and CR2) with different MTF curves but identical detector response (sensitivity) were selected. The plates were characterized by MTF, normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE). Three image quality phantoms were applied to study the impact of the difference in MTF: first, the CDMAM contrast-detail phantom to give gold thickness threshold (T); second, a 3D structured phantom with lesion models (calcifications and masses), evaluated via a 4-alternative forced-choice study to give threshold diameter (dtr) and third, a detectability index (d') from a 50 mm PMMA flat field image and an 0.2 mm Al contrast square. MTF coefficient of variation was ∼1%, averaged up to 5 mm-1. At 5 mm-1, a significant 24% reduction in MTF was observed. The lower MTF caused a 12% reduction in NNPS for CR2 compared to CR1 (at detector air kerma 117 μGy). At 5 mm-1, there was a drop in DQE of 34% for CR2 compared to CR1. For the test objects, there was a trend to lower detectability for CR2 (lower MTF) for all but one parameter, however none of the changes were significant. The MTF is a sensitive and easily applied means of tracking changes in sharpness before these changes are uncovered using lesion simulating objects in test objects.

Original languageEnglish
Title of host publicationMedical Imaging 2019
Subtitle of host publicationPhysics of Medical Imaging
EditorsHilde Bosmans, Guang-Hong Chen, Taly Gilat Schmidt
ISBN (Electronic)9781510625433
Publication statusPublished - 1 Jan 2019
EventMedical Imaging 2019: Physics of Medical Imaging - San Diego, United States
Duration: 17 Feb 201920 Feb 2019

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceMedical Imaging 2019: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego


  • Digital mammography
  • Image quality
  • MTF
  • Quality control
  • Sharpness


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