PTAB

IPR2016-00842

Elekta Inc v. Varian Medical Systems Intl AG

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Apparatus for Planning and Delivering Radiation to a Subject
  • Brief Description: The 7,906,770 patent discloses methods and software for planning radiation therapy treatments. The system defines a treatment plan using an initial set of "control points" along a trajectory of a radiation source, then iteratively optimizes radiation delivery parameters until termination conditions are met, at which point more control points can be added to further refine the plan.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claim 68 is anticipated by Otto ’530 under 35 U.S.C. §102.

  • Prior Art Relied Upon: Otto ’530 (Application # 2003/0086530).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Otto ’530, a prior art application from the same inventor as the ’770 patent, discloses every limitation of claim 68. Otto ’530 describes a method for planning radiation therapy that defines optimization goals (claimed as "termination criteria") and uses an initial plurality of control points (disclosed as "sub-fields" with associated parameters like MLC leaf positions and collimator angles). Crucially, Otto ’530 explicitly teaches that upon reaching a point of diminishing returns in optimization (the claimed "initial termination conditions"), the system can "commence with a few sub-fields and to increase the number of sub-fields as the method proceeds," which directly corresponds to the claim limitation of adding more control points to obtain an increased plurality. The optimization is then repeated with the increased number of control points.

Ground 2: Obviousness - Claim 68 is obvious over Earl ’261 in view of Otto ’530 under 35 U.S.C. §103.

  • Prior Art Relied Upon: Earl ’261 (Application # 2004/0071261) and Otto ’530 (Application # 2003/0086530).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Earl ’261 teaches a computerized inverse-planning method for Intensity-Modulated Radiation Therapy (IMRT) and Intensity-Modulated Arc Therapy (IMAT). It discloses using an iterative optimization process based on clinical objectives (optimization goals) to determine parameters for an initial plurality of control points (e.g., beam angles, aperture shapes, and weights) along a radiation source's trajectory. Petitioner argued that to the extent Earl ’261 does not explicitly disclose the step of adding more control points after the initial optimization process stalls, Otto ’530 supplies this teaching.
    • Motivation to Combine: A POSITA would combine Otto ’530’s technique of progressively adding control points (sub-fields) with the optimization process of Earl ’261 for a clear and predictable benefit. This combination would refine the optimization, prevent the system from getting stuck in a suboptimal solution when iterations cease to yield significant improvement, and ultimately produce a better, more conformal radiation plan in a more efficient manner.
    • Expectation of Success: A POSITA would have had a high expectation of success in implementing this combination, as it involved applying a known technique (progressive optimization from Otto ’530) to improve a similar, known system (the optimization framework of Earl ’261).

Ground 3: Obviousness - Claim 68 is obvious over Duthoy in view of Otto ’530 under §103.

  • Prior Art Relied Upon: Duthoy (a 2003 journal article on IMAT) and Otto ’530 (Application # 2003/0086530).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Duthoy discloses an IMAT planning and delivery strategy that explicitly uses the industry term "control points" to define a sequence of machine states along an arc-based trajectory. Duthoy describes an iterative optimization process for these control points (involving leaf positions and monitor unit values) to achieve a desired dose distribution based on a biophysical objective function. As with the Earl ’261 combination, Petitioner argued that Otto ’530 provides the teaching of adding more control points upon reaching termination conditions, a step not explicitly detailed in Duthoy.
    • Motivation to Combine: The motivation to combine Duthoy with Otto ’530 was the same as for the Earl ’261 combination. A POSITA would have recognized that the progressive optimization strategy from Otto ’530 could be used to improve the results and efficiency of the optimization process described in Duthoy. Adding control points when the process stagnates was a known method to overcome computational complexity and avoid suboptimal plans.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 68 based on the combination of Meedt (a 2003 journal article on beam direction optimization) and Otto ’530, arguing this combination renders the claim obvious under the Patent Owner's allegedly broader construction of "control point."

4. Key Claim Construction Positions

  • "control point": Petitioner proposed 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 asserted to be consistent with the patent’s specification, which describes discretizing a trajectory into "points." Petitioner argued this construction was necessary to counter the Patent Owner's attempt in related litigation to unreasonably broaden the term to include concepts like "fluence maps," which are not tied to a specific point on a trajectory.
  • "initial termination conditions": Petitioner proposed the construction "criteria indicating termination of initial optimization."
  • "iteratively optimizing": Petitioner proposed the construction "repeatedly modifying parameters to achieve an optimization goal."

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claim 68 of Patent 7,906,770 as unpatentable.