Feasibility of dacryoscintigraphy in normal dogs

The purpose of this study was to evaluate the value of dacryoscintigraphy with Tc-99 m Pertechnetate, which is useful in functional nasolacrimal duct obstruction diagnosis in human medical science, by applying it to normal dogs. Dacryoscintigraphy was performed on six clinically healthy beagle dogs to confirm normal passage of their lacrimal ducts. The scintigraphic images of both lacrimal system were obtained at 5 min, 10 min, and 20 min after Tc-99 m Pertechnetate administration, respectively. If lacrimal duct does not come into view within 20 min, delayed images at 30min, 45min and 60 min were gained. After drawing ROI of left and right canaliculus, lacrimal sac, and nasolacrimal duct acquired after dacryoscintigraphy, we measured each counting rate and developed a counting rate table for each time interval. Of the total of 12 places, 10 (83.3%) showed patency within 20 min, and 11 (91.6%) showed patency within 30 min. In one dog, a functional obstruction of right lacrimal canal was observed. Dacryoscintigraphy could provide useful information about functional and anatomical lacrimal duct obstruction in veterinary medicine as well as in clinical research.