## Facts

- Laserscope owned U.S. Patent No. 6,986,764 covering laser-based methods and systems for vaporizing tissue, including treatment of benign prostatic hyperplasia.
- American Medical Systems was Laserscope’s exclusive licensee.
- The patent describes “photoselective vaporization” in functional terms and discusses wavelength ranges, including statements that certain wavelengths are minimally absorbed by irrigant and selectively absorbed by blood/tissue.
- Some claims expressly include a wavelength limitation (e.g., about 200–650 nm), while other claims permit wavelengths up to about 1,000 nm or contain no wavelength limitation.
- American Medical Systems and Laserscope sued Biolitec, alleging infringement by Biolitec’s Evolvee laser system and methods of use.
- The district court construed “photoselective vaporization of tissue” in the preambles of asserted claims as a limiting element and interpreted it to impose technical wavelength-related requirements drawn from the specification.
- Based on that construction, the district court granted Biolitec summary judgment of noninfringement; plaintiffs appealed.

## Issues

1. Whether the preamble phrase “photoselective vaporization of tissue” is a limiting claim element in the asserted claims.
2. Whether the district court erred by using the preamble to impose wavelength-based restrictions not stated in the bodies of the asserted claims.

## Decision

- The Federal Circuit reversed the summary judgment of noninfringement and remanded.
- The court held that “photoselective vaporization of tissue” in the preamble did not limit the asserted claims.
- The asserted claim bodies were complete and did not require the preamble phrase to define the claimed structure or steps.
- The record did not show clear reliance on the preamble language during prosecution to distinguish prior art.
- The specification’s discussion of particular wavelength ranges could not be imported into claims that omitted those limits, especially where other claims expressly recited them.
- A dissent would have treated the preamble as limiting because of the specification’s linkage between the phrase and wavelength characteristics.

## Legal Principles

- Whether a preamble limits a claim depends on the patent as a whole and the prosecution history; it is not presumed limiting.
- A preamble is generally non-limiting unless it recites essential structure/steps or is necessary to give “life, meaning, and vitality” to the claim.
- When the claim body fully defines the invention, a preamble that states a purpose or intended use ordinarily does not restrict claim scope.
- Courts should not use a preamble to read specification-described features into the claim body where the patentee chose to include those features in some claims but omit them in others.

## Conclusion

The Federal Circuit held that the asserted claims did not require satisfaction of the preamble phrase “photoselective vaporization of tissue” as a substantive limitation, reversed the resulting summary judgment of noninfringement, and remanded for further proceedings under the corrected claim construction.


Am. Med. Sys., Inc. v. Biolitec, Inc., 618 F.3d 1354 (Fed. Cir. 2010)