Best Medical Intl Inc v. Elekta Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Best Medical International, Inc. (Virginia)
  • Defendant: Elekta AB (Sweden), Elekta Holdings U.S., Inc. (Delaware), Elekta Inc. (Georgia), Elekta Ltd. (United Kingdom), and IMPAC Medical Systems, Inc. (Delaware)
  • Plaintiff’s Counsel: Buchanan Ingersoll & Rooney PC
• Case Identification: 1:18-cv-1600, D. Del., 11/05/2018
• Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendants conduct regular business in the state, and certain Defendant entities are incorporated in Delaware. The complaint also notes that some Defendants have previously availed themselves of the Delaware courts by bringing counterclaims in prior litigation.
• Core Dispute: Plaintiff alleges that Defendant’s linear accelerators, when used with its Monaco® treatment planning software, infringe four patents related to methods for computationally optimizing radiation dosimetry plans.
• Technical Context: The technology concerns software-based systems for planning radiation therapy, a critical component of cancer treatment that aims to deliver a lethal dose of radiation to a tumor while minimizing exposure to surrounding healthy tissue.
• Key Procedural History: The complaint references a prior International Trade Commission (ITC) proceeding (Inv. No. 337-TA-968) involving the same accused products. While the patents and complaining parties in that matter were different, the public findings from that investigation regarding the functionality of the accused Monaco® software are cited to support the present infringement allegations.

Case Timeline

Date	Event
1996-10-24	U.S. Patent No. 6,038,283 Priority Date
1998-05-27	U.S. Patent No. 6,393,096 Priority Date
2000-03-14	U.S. Patent No. 6,038,283 Issues
2002-05-21	U.S. Patent No. 6,393,096 Issues
2003-07-11	U.S. Patent No. 7,266,175 Priority Date
2003-08-11	U.S. Patent No. 7,015,490 Priority Date
2006-03-21	U.S. Patent No. 7,015,490 Issues
2007-09-04	U.S. Patent No. 7,266,175 Issues
2018-11-05	Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 6,038,283 - "Planning Method and Apparatus for Radiation Dosimetry"

• Patent Identification: U.S. Patent No. 6,038,283, "Planning Method and Apparatus for Radiation Dosimetry," issued March 14, 2000.

The Invention Explained

• Problem Addressed: The patent describes a central challenge in radiation therapy: eradicating a tumor requires a high radiation dose, but this risks damaging nearby healthy tissue, especially for tumors with complex, concave shapes or varying thickness (’283 Patent, col. 1:14–2:14). Prior computational planning methods were allegedly insufficient because they did not account for the relative clinical importance of different tissue structures or allow physicians to establish desired dose distributions using familiar clinical data representations (’283 Patent, col. 3:20–51).
• The Patented Solution: The invention is a computational method and apparatus for optimizing a radiation treatment plan. It uses an iterative process where a computer compares a "proposed" radiation beam arrangement to a "desired" dose prescription. This comparison is based on partial volume data, which can be represented by Cumulative Dose Volume Histogram (CDVH) curves. The computer iteratively modifies the beam arrangement (e.g., by changing beam weights) and accepts changes that result in a "greater correspondence" to the desired prescription, while rejecting changes that lead to a "lesser correspondence." (’283 Patent, Abstract; col. 4:11–32).
• Technical Importance: This approach allowed clinicians to define complex, multi-variable treatment goals using clinically intuitive CDVH curves, enabling a computer to automatically search for an optimal plan that balanced the competing objectives of tumor eradication and healthy tissue preservation (Compl. ¶¶34–35).

Key Claims at a Glance

• The complaint asserts independent apparatus Claim 25 and dependent Claims 26-28 (Compl. ¶47).
• The essential elements of independent Claim 25 include:
  • a computer, adapted to computationally obtain a proposed radiation beam arrangement;
  • the computer further adapted to computationally change the proposed radiation beam arrangement iteratively, wherein the proposed radiation beam arrangement is changed by changing the beam weights;
  • the computer being further adapted to incorporate a cost function at each iteration to approach correspondence of partial volume data associated with the proposed radiation beam arrangement to partial volume data associated with a pre-determined desired dose prescription;
  • the computer being further adapted to reject the change... if the change... leads to a lesser correspondence to the desired dose prescription and to accept the change... if the change... leads to a greater correspondence... to obtain an optimized radiation beam arrangement.

U.S. Patent No. 6,393,096 - "Planning Method and Apparatus for Radiation Dosimetry"

• Patent Identification: U.S. Patent No. 6,393,096, "Planning Method and Apparatus for Radiation Dosimetry," issued May 21, 2002.

The Invention Explained

• Problem Addressed: The patent addresses the same general problem as the ’283 Patent: optimizing a radiation plan to balance tumor treatment with sparing healthy tissue (’096 Patent, col. 1:14–3:18).
• The Patented Solution: The ’096 Patent also discloses an iterative optimization method using a cost function and CDVHs. However, it adds a specific refinement to the decision-making process. The claimed apparatus is adapted not only to accept or reject changes based on correspondence to a desired dose prescription, but also "to exceed the cost function by a set amount if such excess allows better conformation with the target CDHV curve." (’096 Patent, Abstract; Claim 31). This introduces a more sophisticated trade-off, where a plan that is technically "worse" on an overall cost metric might still be accepted if it achieves a superior match to the specific goals for the tumor target itself.
• Technical Importance: This patented refinement suggests a more nuanced optimization process, giving the system flexibility to prioritize hitting the tumor target accurately, even at the expense of a slight increase in the overall plan's calculated "cost" (Compl. ¶¶35–36).

Key Claims at a Glance

• The complaint asserts independent apparatus Claim 31 and dependent Claims 32-33 (Compl. ¶109).
• The essential elements of independent Claim 31 include:
  • a computer adapted to computationally obtain a proposed radiation beam arrangement;
  • [the computer adapted to] computationally change the proposed radiation beam arrangement iteratively to conform to a target CDVH curve;
  • [the computer adapted to] incorporate a cost function at each iteration to approach correspondence of partial volume data... with a predetermined desired dose prescription;
  • [the computer adapted to] reject the change... if the change... leads to a lesser correspondence to the desired dose prescription and to accept the change... if the change... leads to a greater correspondence...;
  • and [to] exceed the cost function by a set amount if such excess allows better conformation with the target CDHV curve.

U.S. Patent No. 7,266,175 - "Planning Method for Radiation Therapy"

• Patent Identification: U.S. Patent No. 7,266,175, "Planning Method for Radiation Therapy," issued September 4, 2007.
• Technology Synopsis: This patent is directed to methods for controlling the trade-off between "treatment plan delivery efficiency" (e.g., speed, simplicity) and "dosimetric fitness" (e.g., quality of the dose distribution) (Compl. ¶176). The claimed method evaluates an objective cost function that incorporates both a "dosimetric cost term" representing fitness and a "delivery cost term" representing efficiency, allowing for an optimized balance between the two competing factors (Compl. ¶176).
• Asserted Claims: At least independent method Claim 13 is asserted (Compl. ¶178).
• Accused Features: The complaint alleges that the Monaco® system's "Segment Shape Optimization" feature and its use of cost functions to model tissue responses and optimize beam weights and shapes practice the claimed method of balancing dosimetric fitness and delivery efficiency (Compl. ¶¶181, 186, 194).

U.S. Patent No. 7,015,490 - "Method and Apparatus for Optimization of Collimator Angles in Intensity Modulated Radiation Therapy Treatment"

• Patent Identification: U.S. Patent No. 7,015,490, "Method and Apparatus for Optimization of Collimator Angles in Intensity Modulated Radiation Therapy Treatment," issued March 21, 2006.
• Technology Synopsis: This patent concerns an apparatus and method for optimizing the rotational angle of a multi-leaf collimator (MLC), a device that shapes the radiation beam (Compl. ¶225). The invention uses a computer with a cost function to determine a collimator angle that enhances both the "conformity of the radiation beam arrangement to a shape of the target" and "delivery efficiency," the latter by reducing the number of beam segments and monitor units required for treatment (Compl. ¶225).
• Asserted Claims: At least independent apparatus Claim 17 is asserted (Compl. ¶227).
• Accused Features: The complaint alleges that Elekta's LINACs, which contain MLCs, in communication with the Monaco® software infringe this patent (Compl. ¶228). The Monaco® system is alleged to use a cost function to determine the radiation beam arrangement and enhance delivery efficiency through features like "Segment Shape Optimization" and "Max. Sweep Efficiency" (Compl. ¶¶243–245, 248).

III. The Accused Instrumentality

Product Identification

• The accused products are Defendants' linear accelerators ("LINACs"), including the Precise Treatment System™, Versa HD™, Infinity™, Synergy®, and Compact™ models, when used in conjunction with the Monaco® treatment planning system (the "Accused Products") (Compl. ¶¶9, 47).

Functionality and Market Context

• The Monaco® system is described as an "inverse treatment planning system" that uses a computer and software to optimize radiation delivery (Compl. ¶¶33, 35). The system is alleged to use "cost functions" and "constrained optimization" to determine a configuration of radiation "beamlets" with varying intensities that best deliver a prescribed dose to a tumor while satisfying constraints for surrounding healthy tissue (Compl. ¶59). The software allegedly employs a two-stage optimization process and generates dose volume histograms (DVHs) to represent dose distributions (Compl. ¶¶62, 66). Defendants are positioned as a "leading provider" in the radiotherapy field (Compl. ¶38). The complaint includes a figure depicting various cost functions available in the Monaco system, distinguishing between "Biological (dose response-based) Cost Functions" and "Physical (dose-based) Cost Functions" (Compl. p. 16).

IV. Analysis of Infringement Allegations

U.S. Patent No. 6,038,283 Infringement Allegations

Claim Element (from Independent Claim 25)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
an apparatus for determining an optimized radiation beam arrangement... comprising a computer...	The Accused Products include a computer that executes the Monaco® software for planning radiation treatment.	¶58	col. 4:18-20
adapted to computationally obtain a proposed radiation beam arrangement...	The Monaco® software computationally generates a treatment plan, which is a proposed radiation beam arrangement.	¶60	col. 4:18-20
adapted to computationally change the proposed radiation beam arrangement iteratively, wherein the proposed radiation beam arrangement is changed by changing the beam weights...	Monaco® allegedly uses an optimization algorithm to find the best configuration of beam intensities (weights) and iteratively optimizes a simulated dose distribution in stages.	¶¶59, 62, 64	col. 4:21-23
the computer being further adapted to incorporate a cost function at each iteration to approach correspondence of partial volume data associated with the proposed radiation beam arrangement to partial volume data associated with a pre-determined desired dose prescription...	The Monaco® system allegedly uses cost functions and generates dose volume histograms (DVHs), which represent partial volume data, to optimize treatment plans to meet a user-defined prescription.	¶¶65-67	col. 4:23-28
and the computer being further adapted to reject the change... if the change... leads to a lesser correspondence to the desired dose prescription and to accept the change... if the change... leads to a greater correspondence...	Monaco® allegedly iteratively optimizes a simulated dose distribution relative to a set of optimization goals, which implies a process of accepting changes that move closer to the goal and rejecting those that do not.	¶¶69, 71	col. 4:28-32

U.S. Patent No. 6,393,096 Infringement Allegations

Claim Element (from Independent Claim 31)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a computer adapted to... computationally obtain a proposed radiation beam arrangement...	The Monaco® software, running on a computer, generates a treatment plan, which is a proposed radiation beam arrangement.	¶122	col. 4:27-29
computationally change the proposed radiation beam arrangement iteratively to conform to a target CDVH curve...	Monaco® is alleged to use a two-stage process to optimize dose distributions to meet a user-defined prescription and uses DVH functions, which represent CDVH curves. A visual in the complaint shows a dose volume histogram graph used in the system (Compl. p. 27).	¶¶121, 123, 125	col. 4:30-32
incorporate a cost function at each iteration to approach correspondence of partial volume data... with a predetermined desired dose prescription...	The system is alleged to use physical and biological cost functions that have control points and are summed to produce a final cost reflected by a proposed CDVH curve.	¶¶126, 128	col. 4:32-37
reject the change... if the change... leads to a lesser correspondence... and to accept the change... if the change... leads to a greater correspondence...	The complaint cites findings from an ITC matter stating that Monaco® "iteratively optimizes" a simulated dose distribution relative to optimization goals, implying an accept/reject logic.	¶¶130, 132	col. 4:38-44
and to exceed the cost function by a set amount if such excess allows better conformation with the target CDHV curve.	This function is allegedly met through Monaco's use of features like the "Overdose Volume Constraint," a physical cost function that controls the DVH curve at specific points or for doses greater than a threshold. A visual shows how this function controls the DVH curve (Compl. p. 30).	¶¶135, 137	col. 4:44-47

Identified Points of Contention

• Scope Questions: A primary point of contention may be whether the accused Monaco® system's complex, multi-factor "cost functions" operate in a manner that meets the more simplistic "accept/reject" logic based on "correspondence" as claimed in the ’283 Patent. The dispute may focus on whether "approaching correspondence" is a direct equivalent to the claimed iterative decision process.
• Technical Questions: For the ’096 Patent, a key question will be one of functional mapping: does the complaint provide sufficient evidence that features like the Monaco® system's "Overdose Volume Constraint" perform the specific, conditional function of "exceed[ing] the cost function by a set amount if such excess allows better conformation with the target CDVH curve"? The defense may argue that controlling a DVH curve at a point is a standard optimization constraint, not the specific trade-off mechanism claimed.

V. Key Claim Terms for Construction

The Term: "correspondence" (from ’283 Patent, Claim 25)

• Context and Importance: This term is the metric by which the claimed iterative optimization process makes its accept/reject decisions. The definition of "correspondence" is critical because it will determine whether the accused system’s optimization algorithm, which uses its own proprietary cost functions, performs the claimed method.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification describes the goal as to "approach correspondence of a CDVH associated with the proposed radiation beam arrangement to a CDVH associated with a pre-determined desired dose prescription" (’283 Patent, col. 4:23-28). This general language could support an interpretation where any algorithmic step that moves the proposed plan closer to the desired plan satisfies the limitation.
  • Evidence for a Narrower Interpretation: The detailed description discloses a specific mathematical formula for calculating a "zone cost" and a "total cost" based on the area between the proposed and desired CDVH curves (’283 Patent, col. 4:41-66). This could support a narrower construction where "correspondence" is limited to a metric derived from this specific calculation method.

The Term: "exceed the cost function by a set amount" (from ’096 Patent, Claim 31)

• Context and Importance: This phrase defines the novel feature of the asserted claim of the ’096 Patent. The infringement analysis for this patent will likely turn on whether the accused Monaco® system contains a mechanism that performs this specific function. Practitioners may focus on this term because it describes a sophisticated trade-off logic that may not have a direct, one-to-one equivalent in the accused system's user interface or documentation.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent's abstract frames the invention broadly as "increasing or decreasing radiation beam intensity if the change... leads to a greater correspondence" (’096 Patent, Abstract). This could suggest that any trade-off mechanism where one goal (e.g., target conformation) is prioritized over another (e.g., overall cost) could fall within the claim's scope.
  • Evidence for a Narrower Interpretation: The claim language recites a specific, sequential logic: first, a cost function is evaluated, and then a decision is made to "exceed" it under certain conditions. The specification does not appear to provide a detailed embodiment of how this specific "exceeding" step is implemented. This lack of a specific working example may support arguments that the term should be construed narrowly or raises the question of whether the complaint has adequately pleaded how the accused system performs this precise function.

VI. Other Allegations

• Indirect Infringement: The complaint alleges inducement of infringement under 35 U.S.C. § 271(b), stating that Defendants provide training, promotion, and sales of the Accused Products to customers with the intent to cause infringement (Compl. ¶¶77–78, 144–145). It also alleges contributory infringement under § 271(c), asserting the Accused Products constitute a material part of the patented inventions, are not staple articles of commerce, and are known to be especially adapted for infringement (Compl. ¶¶88, 156). Finally, the complaint alleges infringement under § 271(f)(2) for supplying the Monaco® software from the United States with the intent that it be combined with LINAC systems outside the U.S. to practice the patents (Compl. ¶¶95, 164).
• Willful Infringement: For all four patents-in-suit, the complaint alleges that Defendants' infringement was "knowing and willful" (Compl. ¶¶74, 140). The basis for this knowledge is alleged "upon information and belief," stating that Defendants had knowledge of the patents "at all relevant times" without providing specific factual support such as pre-suit notification (Compl. ¶¶76, 143).

VII. Analyst’s Conclusion: Key Questions for the Case

• A core issue will be one of algorithmic equivalence: does the Monaco® system's complex, multi-factor "cost function" optimization perform the specific, sequential "accept/reject" steps based on "correspondence" as recited in the claims of the '283 and '096 patents, or does it use a fundamentally different and non-infringing optimization approach?
• A key evidentiary question will be one of functional mapping: has the Plaintiff provided sufficient technical evidence to demonstrate that features described in Defendant’s product manuals, such as the "Overdose Volume Constraint," actually perform the precise and conditional function of "exceed[ing] the cost function by a set amount if such excess allows better conformation," as required by Claim 31 of the '096 patent?
• The case may also present a question of procedural influence: to what extent will the technical descriptions and findings regarding the Monaco® system's functionality from the prior ITC public record be permitted to shape discovery, claim construction, and infringement arguments in this matter, even though the asserted patents and parties are different?