PTAB

IPR2020-00072

Varian Medical Systems Inc v. Best Medical Intl Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Planning Method and Apparatus for Radiation Dosimetry
  • Brief Description: The ’096 patent describes a method for determining an optimized radiation beam arrangement for radiotherapy. The method uses a computer with a simulated annealing radiotherapy planning (SARP) algorithm to calculate a treatment plan that maximizes radiation to a tumor while minimizing exposure to surrounding healthy tissue, based on user-defined parameters.

3. Grounds for Unpatentability

Ground 1: Claims 43, 44, and 46 are obvious over Carol-1995 in view of Viggars.

  • Prior Art Relied Upon: Carol-1995 (a 1995 journal article describing the "Peacock" treatment planning system) and Viggars (a 1992 journal article describing the "OSCAR" program for evaluating treatment plans).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Carol-1995 disclosed most limitations of independent claim 43, including a computer-implemented simulated annealing process for optimizing a radiation plan. Carol-1995 taught using weighted costs for targets and structures, with user control over "aggressiveness," which Petitioner equated to the claimed "range of values to indicate the importance of objects." Petitioner contended Viggars taught the remaining limitations, specifically determining and entering "desired partial volume data" via its dose prescription methodology, which uses dose-volume limits for specified percentages of organs.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine the teachings to use the quantitative evaluation tools of Viggars’ OSCAR program to assess the clinical acceptability of treatment plans generated by Carol-1995's Peacock system. Viggars provided a systematic, objective method to ensure an optimized plan complied with a clinician's dose prescription requirements.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because Viggars taught that its OSCAR program was developed on a commercial system and could be "used easily on a routine basis" to evaluate the exact type of treatment plan data generated by systems like Peacock.

Ground 2: Claims 43, 44, and 46 are obvious over Curran-5 in view of Carol-2.

  • Prior Art Relied Upon: Curran-5 (a 1997 book chapter on the PEACOCK system) and Carol-2 (a 1997 book chapter from the same book, also on the PEACOCK system).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Curran-5, which describes the PEACOCK system, taught nearly all claim limitations. It disclosed using a computer with simulated annealing, distinguishing between targets and sensitive structures, and providing the user with a range of values (0.0 to 2.0) for "weights" to "determine the relative importance" of different areas. Curran-5 also disclosed "conformality control factors" like an "aggressiveness slider" and slice thickness selection. Petitioner argued that Carol-2, describing the same system, explicitly taught that the system's prescription is entered as "partial volume data," thus directly teaching the remaining limitations.
    • Motivation to Combine: A POSITA would combine the references because they are chapters from the same book describing different features of the same PEACOCK radiotherapy system. Combining them provides a more complete understanding of the system's functionality, with Carol-2 merely clarifying that the dose prescription data discussed in Curran-5 is a form of "partial volume data."
    • Expectation of Success: Success would be assured, as the combination involved integrating knowledge about a single, pre-existing, and operational commercial system.

Ground 3: Claims 43, 44, and 46 are obvious over Curran-5 in view of Carol-17.

  • Prior Art Relied Upon: Curran-5 (the 1997 book chapter on the PEACOCK system) and Carol-17 (another 1997 chapter from the same book, describing the CORVUS inverse planning system).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground relied on Curran-5 for the same core teachings as Ground 2. It then used Carol-17 to supply the teachings related to using "partial volume information" as the basis for optimization. Carol-17 described the CORVUS system, which featured a more "clinically relevant" and "experience friendly" user interface specifically designed for entering partial volume data (e.g., goal, min/max dose, and percent volume) for each target and structure.
    • Motivation to Combine: A POSITA would combine the teachings to improve the existing PEACOCK system (disclosed in Curran-5) by incorporating the more advanced user interface and partial volume data entry methods of the CORVUS system (disclosed in Carol-17). Carol-17 explicitly highlighted the benefits of defining treatment goals using partial volumes, providing a clear reason to modify older systems to include this improved functionality.
    • Expectation of Success: A POSITA would reasonably expect success because the proposed modification was primarily to the system's user interface to allow for a more detailed, but conceptually similar, method of data entry. This was presented as a routine software modification.

4. Key Claim Construction Positions

  • Petitioner argued that the limitation in claim 43, "using the computer to computationally calculate an optimized radiation beam arrangement," should be construed as a means-plus-function element under 35 U.S.C. §112, ¶6.
  • Petitioner contended that the term "computer" is a generic, "black box" term that fails to recite a sufficiently definite structure for performing the specialized claimed function.
  • Under this construction, Petitioner identified the corresponding structure in the ’096 patent’s specification as "a computer programmed with a simulated annealing radiotherapy planning (SARP) optimization algorithm." This construction was central to Petitioner's arguments, as the prior art references all disclosed computer systems implementing SARP algorithms for treatment planning.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 43, 44, and 46 of the ’096 patent as unpatentable.