Acquisition
The acquisition is performed with patient sested in front of the Gammacamera with pinhole or high resolution collimator and appropiate zoom factor in anterior view and obliques.
Start imaging inmediately after eye instillation of 99m-Tc DTPA drops. Its administration is best with finest needle and syringe available, e.g. a tuberculin one (25G x 5/8 or 27G x 1/2).
Either a dynamic procedure or serial static views for 20-30 min are adequate. Obliques are useful to demonstrate flow to nasal and pharingeal regions. In those patients with epiphora, make sure to clean tears with a cotton tip to prevent skin contamination and making easier the study interpretation.
References:
1 Hulsey JM, Smith R. Obstructive pattern in dacryoscintigraphy. Semin Nucl Med. 1988 Jan;18(1):65-7.
2 Ergin NT, Akman A, Aktas A, Aydin P, Akkuzu B. Evaluation of nasolacrimal duct function in chronic paranasal sinus infectionswith 99mTc dacryoscintigraphy. Laryngorhinootologie. 1999 Jul;78(7):382-6.