The developer of a breast cancer screening device is going after Fujifilm Medical Systems for patent infringement after it introduced its own equipment in the United States this year.

In its federal lawsuit filed in U.S. District Court for the District of Connecticut Monday, Hologic Inc. claims Fujifilm infringed five of its mammogram technology patents. The lawsuit claims the Japanese company, which has offices in Stamford, “had specific intent to infringe the ’296 Patent or were willfully blind to such infringement.”