§112, ¶6 Claim Element Limited by Disclosed Embodiment

By Firasat M. Ali and Arturo E. Sandoval

The U.S. Court of Appeals for the Federal Circuit, affirming the grant of summary judgment of non-infringement, held that structure corresponding to an independent means-plus-function claim must be interpreted by reference to the written description, not by limitations contained in a dependent claim. Since the written description disclosed only one embodiment, which was neither the same as nor structurally equivalent to the alleged infringing device, the accused device that performed the claim function was found not to infringe. Nomos Corporation v. BrianLab, Inc., 357 F.3d 1364 (Fed. Cir. 2004) (Mayer, Chief J.)

This case involves an ultrasonic device used in a patient positioning system for administering radiation therapy. The process involves generating an ultrasonic image using an ultrasonic probe and comparing the generated image to a prior image obtained through a computerized tomographic (CT) scan. Since cancerous lesions move with time, the image generated by the ultrasonic device at the time treatment is administered is used in order to fine tune and determine the present location of the lesion.

The independent claim in issue included a means-plus-function claim element that recited "a means for generating at least one ultrasound image." The corresponding structure described in the specification was limited to a single embodiment that included an ultrasonic probe and a fixation device for securing the probe to the treatment table in a specific fashion. After a Markman hearing, the district court construed this element as limited to a fixed ultrasonic probe having a fixation device that maintains the probe perpendicular to the treatment table and to equivalents. Since the alleged infringing device was a handheld ultrasonic device that could be moved as desired by a physician, the district court found it did not infringe. In reaching this conclusion the court stated that in order to infringe a means-plus-function claim, the structure of the accused device must be compared with the disclosed structure and equivalent structures and an identical function must be found. The court found that while the claimed...