The U.S. International Trade Commission said last week that it will begin an investigation into alleged Tariff Act violations by Elekta (STO:EKTA B), based on a complaint by arch-rival Varian Medical (NYSE:VAR).

Varian makes the TruBeam and VitalBeam radiotherapy systems, which compete with Elekta’s Versa HD and Infinity devices.

The ITC said Oct. 26 that it would open the probe based on a Sept. 25 complaint by Palo Alto, Calif.-based Varian against Elekta and several subsidiaries in Sweden, the U.K., Germany, China and the U.S., including Impac Medical Systems of Sunnyvale, Calif.

Varian’s complaint seeks an exclusion order and a cease & desist order, the ITC said. The company also filed a pair of lawsuits against Elekta in federal courts in Delaware and California, alleging infringement of 4 patents by Elekta’s GammaKnife Icon, Versa HD, Axesse, Infinity, Synergy, Agility and VMAT (Monaco) products, according to court documents.

“We do not foresee any material business impact as a result of these claims. They are apparently part of Varian’s legal strategy against a lawsuit from William Beaumont Hospital and Elekta Ltd. earlier this year,” Elekta president & CEO Tomas Puusepp said in prepared remarks.

Elekta sued Varian last June in a Michigan federal court, alleging infringement of a trio of patents covering “Cone-beam computed tomography with a flat-panel imager” by Varian’s TrueBeam device.

Apart from their most recent hostilities, the 2 companies have a history of fractiousness that’s reached as far afield as the Centers for Medicare & Medicaid Services.