For computer-implemented means-plus-function elements relying on algorithm structure, “[t]he algorithm need only include what is necessary to perform the claimed function.” It “[does] not need to include every possible implementation of the function, so long as it [is] linked to and encompasse[s] the claimed function.”
Background / Facts: The patent being asserted here is directed to reducing damage to healthy tissue during radiation therapy treatment by synchronizing a radiation treatment beam with a patient’s movements (e.g., breathing). This may be achieved using natural or artificial “fiducials” to detect patient movement (e.g., natural moles on the skin or artificial reflectors placed on the skin). The parties agree that the claimed “means determining movement of said patient” limitation is a means-plus-function term, but do not agree on what structure in the patent’s written description perform the claimed function.
Issue(s): Whether the disclosed structure is limited to a computer processor programmed to perform the specific examples illustrated in the figures as opposed to a broader two-step algorithm generalizing those example operations.
Holding(s): No. The “patent discloses—and specifically links—the function of detecting patient movement to the [broader] two-step algorithm.” In particular, “the written description discloses that patient movement is detected by first identifying fiducials and then tracking those fiducials … [T]he written description links this algorithm to the function of determining patient movement.” Although the figures illustrate more specific implementation details, the patent specifically states that “the figures in the patent are merely implementations of the algorithm.” Thus, “[w]hile those steps are described in the written description, they are not required. In other words, while the written description describes certain implementations of the algorithm, it expressly notes that other implementations are possible.” The accused infringer’s “attempt to pick and choose which steps it deems necessary by synthesizing steps from disparate portions of the written description is too limiting. The algorithm need only include what is necessary to perform the claimed function.”