Barts and The London NHS Trust 1 article published in JoVE Medicine In Vivo Imaging and Tracking of Technetium-99m Labeled Bone Marrow Mesenchymal Stem Cells in Equine Tendinopathy Jayesh Dudhia1, Patricia Becerra2, Miguel A. Valdés2, Francisco Neves2, Neil G. Hartman3, Roger K.W. Smith1 1Department of Clinical Science and Services, The Royal Veterinary College, 2Hospital de Referencia La Equina, Manilva, 3Department of Nuclear Medicine, Barts & The London NHS Trust This protocol describes the radiolabeling of equine mesenchymal stem cells and their implantation into tendon injuries in the horse in order to determine cell survival and tissue distribution using gamma scintigraphy.