The U.S. Supreme Court has refused to hear appeals on a $44.9 million verdict against a French manufacturer accused of infringing on patents for crystal technology used by Siemens to make PET scanners, Bloomberg News reports.

On Tuesday, the court refused to hear the appeal from Saint-Gobain S.A., which lost a 2007 case against Siemens over scintillator crystals used to convert gamma rays into light, Bloomberg said.

Siemens filed the original suit in a Delaware District Court after Saint-Gobrain sold some crystals to Philips Medical Systems to use in its own PET machines, according to court documents. Philips is not involved in the suit.

At issue in the appeals was the standard the jury was given for deciding whether the crystal technology patent awarded to Saint-Gobain infringed on an earlier Siemens patent.

Siemens holds U.S. Patent No. 4,958,080, for crystals made from cerium-doped lutetium oxyorthosilicate. Saint-Gobain has a non-exclusive license for U.S. Patent No. 6,624,420, for cerium-doped lutetium-yttrium orthosilicate, in which 10 percent of the lutetium atoms in the crystal are replaced by yttrium atoms, according to a filing in support of the ruling by the U.S. Solicitor General. This patent lists Siemens' patent in its "prior art" statement, the filing said.

In the initial lawsuit, the Delaware District Court asked the jury to decide whether infringement had occurred according to the "doctrine of equivalents" using the preponderance of evidence standard, rather than the much tougher "clear and convincing" standard urged by Saint-Gobain. A Federal Circuit Court upheld the lower court's reliance on the preponderance of evidence standard.

In its filings, the Obama administration sided with the lower court rulings, arguing in part that the preponderance of evidence standard is the typical one for patent infringement cases.

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