Mallinckrodt (plaintiff) owned a patent for a device used to treat pulmonary disease. The device delivered medication to the lungs in aerosol mist form. Mallinckrodt manufactured, packaged, and sold the device to hospitals. The device was labeled “Single Use Only” and came with instructions to dispose of it according to the appropriate biohazardous-waste standards after one use. Instead of adhering to these instructions, after using the device, some hospitals shipped the used devices to Medipart, Inc. (Medipart) (defendant). Medipart then sent the devices to Radiation Sterilizers, Inc. (Radiation) for sterilization. Thereafter, Radiation returned the devices to Medipart, where the devices were reassembled, repackaged, and shipped back to the hospital for reuse. Mallinckrodt sued Medipart, claiming infringement and inducement of infringement of the patent through violation of the single-use restriction. Medipart moved for summary judgment, contending that the restriction was unenforceable under the doctrine of patent misuse. The district court granted the motion, concluding that the restriction was unenforceable as a matter of law. Mallinckrodt appealed.