Lantheus Holdings, Inc. engages in the development, manufacture and commercialization of diagnostic medical imaging agents and products that assist clinicians in the diagnosis and treatment of cardiovascular and other diseases. Its products are used by cardiologists, nuclear physicians, radiologists, internal medicine physicians, sonographers and technologists working in a variety of clinical settings. The firm operates through the following geographical segments: U.S. and International. The U.S. segment produces and markets medical imaging agents and products throughout the U.S. This segment sells its products to radio pharmacies, integrated delivery networks, hospitals, clinics and group practices. The International segment operations consist of production and distribution activities in Puerto Rico and direct distribution activities in Canada. The company was founded in 1956 and is headquartered in North Billerica, MA.