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Specification Limits the Invention Even in the Absence of Explicit Claim Language

February 24, 2011

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Last Month at the Federal Circuit - March 2011

Judges: Newman, Friedman (dubitante), Lourie (author)

[Appealed from: N.D. Cal., Senior Judge Whyte]

In Hologic, Inc. v. SenoRx, Inc., No. 10-1235 (Fed. Cir. Feb. 24, 2011), the Federal Circuit reversed the district court’s SJ finding of invalidity because it was based on an erroneous claim construction.

Hologic, Inc. (“Hologic”) owns U.S. Patent No. 6,482,142 (“the ’142 patent”), which discloses a balloon brachytherapy device with a means for providing a predetermined asymmetric isodose profile within a target tissue.  Balloon brachytherapy is a type of radiation therapy in which a balloon is inserted into the body at or near a tumor or other proliferative tissue disease site.  Hologic brought suit against SenoRx, Inc. (“SenoRx”) alleging that SenoRx’s balloon brachytherapy device infringed its patents.  SenoRx conceded infringement of claims 1 and 8 of the ’142 patent but argued that the asserted claims were invalid.

The district court construed the following language in claim 1, “the radiation source further being asymmetrically located and arranged within the expandable surface to provide predetermined asymmetric isodose curves with respect to the apparatus volume,” to require that the radiation source be “located and arranged inside the expandable surface so as not to be concentric with the expandable outer surface,” and did not limit the claimed asymmetry to asymmetry about the longitudinal axis as Hologic had argued.  The district court similarly construed “predetermined asymmetric isodose curves” in both claims to mean “isodose curves determined before radiation is administered which are not substantially the same shape as the apparatus volume and/or not concentric with the apparatus volume.”

Additionally, the district court denied SenoRx’s motion for SJ of invalidity based on the inoperability of language in claim 1 that required a radiation source disposed completely within the expandable outer surface but also spaced apart from the apparatus volume, finding that the intended meaning of the claim was that the source was located within the balloon but spaced apart from its surface.  Additionally, based on its claim constructions, the district court granted SenoRx’s motion for SJ of invalidity of claim 1 of the ’142 patent, as anticipated by the prior art, but denied SenoRx’s motion with respect to claim 8.  At trial, however, the jury, instructed by the district court as to its claim constructions, found claim 8 anticipated and obvious in light of the prior art, and the district court subsequently entered judgment for SenoRx.

On appeal, the Federal Circuit found that the district court erred by not limiting claim 1 to situations in which asymmetry was achieved by displacing the radiation source from the longitudinal axis.  First, the Court noted that asymmetry is a relative concept that can only exist in relation to some reference.  “Here, claim 1 does not specify a reference for the asymmetry of the radiation source’s placement within the expandable surface; however, the specification makes clear what the inventors contemplated as their invention.”  Slip op. at 13.  Specifically, the Federal Circuit explained that each description of the invention contemplating the placement of a radiation source described displacement from the longitudinal axis of the balloon.  Further, while there was one sentence in the specification that did not specify any reference for its asymmetry, the Court rejected SenoRx’s argument that it supported the broader reading of claim 1.  In particular, the Court found that the sentence was the first in a paragraph that included two descriptions of asymmetry about the longitudinal axis and, thus, was simply a prelude to those descriptions, and consistent with the rest of the specification.

Second, the Federal Circuit rejected the district court’s conclusion that claim differentiation between claims 1 and 6 supported its claim constructions.  In so doing, the Court also rejected Hologic’s argument that looking to other terms is only appropriate when the comparison is between an independent claim and the claims that depend from it.  Here, claim 6 referred to a plurality of radiation sources and allowed for some of those sources to be on the longitudinal axis while some are displaced by the changed shape of at least one of the “elongate members” or lumens.  The Federal Circuit indicated that claim 1, however, did not refer to “elongate members” and thus may require less specificity in explaining the shape and location of sources with respect to each other.  The Court then noted that “[d]ifferent terms or phrases in separate claims may be construed to cover the same subject matter where the written description and prosecution history indicate that such a reading . . . is proper.”  Id. at 15-16 (alterations in original) (citation omitted).  In this instance, the Court found that although the claims were worded sufficiently differently, there was no indication that this particular difference should result in an entirely different reading of the asymmetry of the radiation source in claim 1 that was not called for by the plain language of the claim and was not otherwise supported by the specification.

The Federal Circuit also rejected SenoRx’s argument that certain figures in the ’142 patent showed asymmetry with respect to the apparatus volume, but not with respect to the longitudinal axis.  Ultimately, the Court found that the specification, including the figures, consistently and exclusively shows radiation sources located asymmetrically about the longitudinal axis, and because that was clearly what the inventors of the ’142 patent conceived, claim 1 was properly construed as referencing radiation sources that are located and arranged so as not to be on the longitudinal axis of the expandable surface.

Additionally, the Federal Circuit rejected SenoRx’s alternative argument that, even under Hologic’s proposed claim construction, the ’142 patent was invalid as anticipated.  The Court declined to find on appeal, based on a single figure in a prior art reference upon which SenoRx relied, that the reference disclosed asymmetry about the longitudinal axis, as a matter of law.

Finally, the Federal Circuit agreed with the district court that claim 1 was not invalid as inoperable and not enabled.  Specifically, “although ‘apparatus volume’ was an odd choice of language to describe what the inventor intended to describe, its use was consistent in the claim, in accordance with use in the prosecution history, and it results in coverage of the embodiments disclosed.”  Id. at 18-19 (citation omitted).

Accordingly, the Federal Circuit reversed the district court’s grant of SJ of invalidity of claim 1 and the district court’s judgment of invalidity of claim 8, remanded for further proceedings, and awarded costs to Hologic.

Judge Friedman, in an opinion dubitante, disagreed with the majority’s construction of claim 1.  As he explained, independent claims 2 and 6 shed light on the meaning of claim 1 because they both explicitly refer to “solid radiation sources,” or “a radiation source,” followed in each instance by the words “with respect to a longitudinal axis through the apparatus volume.”  In Judge Friedman’s view, the use of the term “a longitudinal axis” in those two claims shows that “when the patentee wanted the claim to include that limitation he knew how to do so, i.e., by explicitly including those words.”  Friedman op. dubitante at 2.  Thus, Judge Friedman would find that the district court correctly construed claim 1 as not including the “longitudinal axis” limitation because the patentee did not include that limitation in the claim.


Summary authored by Sheetal S. Patel, Esq.