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Design and evaluation of an external filter technique for exposure equalization in mammography
Author(s) -
Keshavmurthy Shyam P.,
Goodsitt Mitchell M.,
Chan HeangPing,
Helvie Mark A.,
Christodoulou Emmanuel
Publication year - 1999
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598659
Subject(s) - mammography , filter (signal processing) , imaging phantom , equalization (audio) , computer science , filter design , digital mammography , computer vision , artificial intelligence , medicine , nuclear medicine , breast cancer , algorithm , decoding methods , cancer
We are developing an external filter method for equalizing x‐ray exposure in the peripheral region of the breast. This method requires the use of only a limited number of custom‐built filters for different breast shapes in a given view. This paper describes the design methodology for these external filters. The filter effectiveness was evaluated through a simulation study on 171 mediolateral and 196 craniocaudal view digitized mammograms and through imaging of a breast phantom. The degree of match between the simulated filter and the individual 3‐D exposure profiles at the breast periphery was quantified. An analysis was performed to investigate the effect of filter misalignment. The simulation study indicates that the filter is effective in equalizing exposures for more than 80% of the breast images in our database. The tolerance in filter misalignment was estimated to be about ±2 mm for the CC view and ±1 mm for the MLO view at the image plane. Some misalignment artifacts were demonstrated with simulated filtered mammograms.