Jurgen Jacobs, Presenter: Nothing to Disclose

Kim Lemmens, Abstract Co-Author: Nothing to Disclose

Ferid Shannoun MSc, Abstract Co-Author: Nothing to Disclose

Guy Jacques Marchal MD, PhD, Abstract Co-Author: Nothing to Disclose

Hilde Bosmans PhD, Abstract Co-Author: Nothing to Disclose

The European guidelines for quality control (QC) of digital mammography (EUREF) have been adopted in several European Member States. Its practical implementation is thus a prerequisite for certification as digital mammography screening unit. We report on the development and the first results of an automated daily QC environment for remote multi center follow up of digital mammography units.

Exposures of a homogeneous plate of PMMA are made daily under clinical conditions. These images are sent to our locally installed analysis software. The mean pixel value, standard deviation and signal-to-noise ratio are calculated for the complete image, for 6 reference regions of interest (ROIs) and for series of ROIs all over the image. Deviating pixels and deviating ROIs are defined and the size of bad pixel clusters is determined. Several pixel value profiles are made. These parameters are summarized in maps that are treated as thumbnail images. Analysis results and thumbnail images are sent to the reference site where they are supervised by a trained physicist and compared with previous tests. This set-up has been tested over a time period of 6 months with 15 digital mammography units in Belgium (8 Fuji CR Profect, 2 Siemens Novation DR, 1 Agfa DM1000 DR, 1 Hologic DR and 1 Agfa CR85) and Luxembourg (1 Fuji CR Profect and 1 Siemens Novation DR).

The implementation of our software was successful and the procedure could be integrated in the workflow of each vendor. After a 10 minutes training session radiographers were able to perform the test themselves. Several artifacts could be traced with the thumbnail images. These include: dirt on phosphor cassettes, occasional grid problems and burnt-in markers for CR units. Increasing ghost image factors, lag images, crystallization of detector material and bad pixel calibration were noticed on DR units.

Our initial experience indicates that problems with digital mammography devices can be traced by using thumbnail images of the above parameters.

Consistent constancy check procedures are important in screening environments. The proposed (largely automatic) procedure makes quality control of digital mammography an efficient investment.

Jacobs, J, Lemmens, K, Shannoun, F, Marchal, G, Bosmans, H, Automated Constancy Check in Digital Mammography: Implementation and First Results of a Multicenter Study.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5012549.html