Elekta, Inc. v. Varian Medical Systems International AG

1. Case Identification

• Patent #: 7,906,770
• Filed: April 4, 2016
• Petitioner(s): Elekta Inc.
• Patent Owner(s): Varian Medical Systems, Inc. and Varian Medical Systems International AG
• Challenged Claims: 68

2. Patent Overview

• Title: Methods and Apparatus for Planning and Delivering Radiation
• Brief Description: The ’770 patent discloses methods and systems for planning and delivering radiation therapy. The invention centers on an optimization process that determines radiation delivery parameters (e.g., beam shape, intensity) at a series of "control points" along a trajectory of a rotating radiation source. A key feature is a progressive optimization method that can begin with an initial number of control points and subsequently add more to refine the treatment plan.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 68 under 35 U.S.C. §102

• Prior Art Relied Upon: Otto (Application # 2003/0086530).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Otto, a prior art application from the same inventor as the ’770 patent, disclosed every element of claim 68. Otto taught a method for controlling a radiotherapy device using a computer system to plan a desired dose distribution. It described using optimization techniques with defined goals (termination criteria), specifying an initial set of control points (sub-fields with associated parameters like leaf positions and collimator angles) along a gantry's rotational trajectory, and iteratively optimizing these parameters. Crucially, Otto disclosed the same "smaller-then-larger" optimization technique, teaching that it is desirable to "commence with a few sub-fields and to increase the number of sub-fields as the method proceeds" upon determining that further iterations are not producing significant improvement. This process of adding more control points and continuing optimization was asserted to meet the final limitations of claim 68.

Ground 2: Obviousness of Claim 68 under 35 U.S.C. §103

• Prior Art Relied Upon: Earl (Application # 2004/0071261) and Otto (Application # 2003/0086530).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Earl disclosed a computerized, iterative optimization method for planning radiation therapy (IMRT or IMAT). Earl taught defining clinical objectives (optimization goals), specifying an initial set of control points (e.g., beam angles, aperture shapes) along a trajectory, and iteratively optimizing parameters to improve a dose distribution quality score. Petitioner contended that Earl taught every element of claim 68 except for the explicit step of adding more control points after reaching an initial termination condition.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would have been motivated to modify the optimization process of Earl with the teachings of Otto. Otto explicitly taught the benefits of a progressive optimization where additional sub-fields (control points) are added when the process with the initial set stalls. A POSITA would combine Otto’s technique with Earl’s system to refine the optimization process, prevent redundant or unproductive iterations, and ultimately achieve a better clinical result than simply stopping at a suboptimal solution.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination, as it involved applying a known optimization strategy (from Otto) to improve a similar, known optimization framework (from Earl).

Ground 3: Obviousness of Claim 68 under §103

• Prior Art Relied Upon: Duthoy (a 2003 journal article) and Otto (Application # 2003/0086530).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Duthoy disclosed an IMAT planning strategy that explicitly used the term "control points" to describe a sequence of machine states along a treatment arc. Duthoy taught optimizing these control points to achieve a desired dose distribution based on a biophysical objective function. Like the argument against Earl, Petitioner asserted Duthoy taught all elements of claim 68 except for the step of adding more control points upon reaching a termination condition.
  • Motivation to Combine: The motivation to combine Duthoy with Otto was the same as for Earl. A POSITA would have recognized the value of Otto’s progressive optimization technique and would have been motivated to incorporate it into Duthoy’s system to improve efficiency and the quality of the final treatment plan. Adding control points when optimization slows was a known method to overcome computational complexity and improve results.

Ground 4: Obviousness of Claim 68 under §103 (Alternative Ground)

• Prior Art Relied Upon: Meedt (a 2003 journal article) and Otto (Application # 2003/0086530).
• Core Argument for this Ground:
  • Key Aspects: This ground was presented as an alternative argument, contingent on the Patent Owner’s allegedly broad construction of "control point" from a related ITC investigation to encompass concepts like "fluence maps."
  • Prior Art Mapping: Under this broad construction, Petitioner argued Meedt taught the use of "control points" by disclosing a method of sequentially building up an "evolving beam configuration" by iteratively adding new beam directions. Meedt taught optimizing the fluence profiles (a parameter of the "control point") for all beams at each iteration. The addition of each new beam direction after optimizing the previous set was argued to meet the limitation of adding control points upon reaching a termination condition (the end of the prior optimization step).
  • Motivation to Combine: To the extent Meedt was seen as not explicitly teaching the full claimed method, a POSITA would have combined it with Otto. Otto would provide the well-understood method of adding control points specifically to improve a stalled optimization, as well as the explicit teaching of a computer-based system to automate the process, which would have been an obvious modification to Meedt's algorithm.

4. Key Claim Construction Positions

• "control point": Petitioner argued this term should be construed as "a set of one or more radiation delivery parameters associated with a point along the trajectory of the radiation source." This construction was central to the petition, as Petitioner contended it was the proper technical meaning and that the Patent Owner was attempting to use an unreasonably broad definition in parallel litigation.
• "initial termination conditions": Proposed as "criteria indicating termination of initial optimization."
• "iteratively optimizing": Proposed as "repeatedly modifying parameters to achieve an optimization goal."
• Petitioner noted that the Patent Owner had previously agreed to its proposed constructions for the latter two terms in a related ITC proceeding, making the definition of "control point" the primary point of dispute.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claim 68 of Patent 7,906,770 as unpatentable under 35 U.S.C. §§ 102 and 103 based on the asserted grounds.