title: Force balancing in mammographic compression.
abstract: OBJECTIVE
  In mammography, the height of the image receptor is adjusted to the patient before compressing the breast. An inadequate height setting can result in an imbalance between the forces applied by the image receptor and the paddle, causing the clamped breast to be pushed up or down relative to the body during compression. This leads to unnecessary stretching of the skin and other tissues around the breast, which can make the imaging procedure more painful for the patient. The goal of this study was to implement a method to measure and minimize the force imbalance, and to assess its feasibility as an objective and reproducible method of setting the image receptor height.
  
  
  METHODS
  A trial was conducted consisting of 13 craniocaudal mammographic compressions on a silicone breast phantom, each with the image receptor positioned at a different height. The image receptor height was varied over a range of 12 cm. In each compression, the force exerted by the compression paddle was increased up to 140 N in steps of 10 N. In addition to the paddle force, the authors measured the force exerted by the image receptor and the reaction force exerted on the patient body by the ground. The trial was repeated 8 times, with the phantom remounted at a slightly different orientation and position between the trials.
  
  
  RESULTS
  For a given paddle force, the obtained results showed that there is always exactly one image receptor height that leads to a balance of the forces on the breast. For the breast phantom, deviating from this specific height increased the force imbalance by 9.4 ± 1.9 N/cm (6.7%) for 140 N paddle force, and by 7.1 ± 1.6 N/cm (17.8%) for 40 N paddle force. The results also show that in situations where the force exerted by the image receptor is not measured, the craniocaudal force imbalance can still be determined by positioning the patient on a weighing scale and observing the changes in displayed weight during the procedure.
  
  
  CONCLUSIONS
  In mammographic breast compression, even small changes in the image receptor height can lead to a severe imbalance of the applied forces. This may make the procedure more painful than necessary and, in case the image receptor is set too low, may lead to image quality issues and increased radiation dose due to undercompression. In practice, these effects can be reduced by monitoring the force imbalance and actively adjusting the position of the image receptor throughout the compression.
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands and Sigmascreening B.V., Meibergdreef 45, Amsterdam 1105 BA, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: Branderhorst
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands and Sigmascreening B.V., Meibergdreef 45, Amsterdam 1105 BA, The Netherlands.
authors.forename: J E
authors.initials: JE
authors.lastname: de Groot
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: L M F H
authors.initials: LM
authors.lastname: Neeter
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands and Sigmascreening B.V., Meibergdreef 45, Amsterdam 1105 BA, The Netherlands.
authors.forename: M G J T B
authors.initials: MG
authors.lastname: van Lier
authors.affiliation: Sigmascreening B.V., Meibergdreef 45, Amsterdam 1105 BA, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Neeleman
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: den Heeten
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center, P.O. Box 22660, Amsterdam 1100 DD, The Netherlands and Sigmascreening B.V., Meibergdreef 45, Amsterdam 1105 BA, The Netherlands.
authors.forename: C A
authors.initials: CA
authors.lastname: Grimbergen
mesh_terms: D006801:Humans; D008327:Mammography / Q000295:instrumentation*; D055595:Mechanical Phenomena