1*WHEN OBSTRUCTION IS DIAGNOSED, THE TRACER SHOULD BE WASED OUT PHYSICALLY TO REDUCE THE RADIATION DOSE TO THE EYE. THIS IS MINIMAL FOR A NORMAL SYSTEM, BUT MAY BE SEVERAL HUNDRED TIMES HIGHER IN AN OBSTRUCTED SYSTEM WHICH IS NOT IRRIGATED*

2*IT IS IMPORTANT TO IMAGE CONTINUOUSLY AND LOOK FOR VISUALIZATION OF THE SAC AS WELL AS CLEARANCE OF TRACER FROM THE EYE*

3*THE LACRIMAL DRAINAGE SCAN PROVIDES MORE FUNCTIONAL INFORMATION THAN AN X-RAY DCG BECAUSE:
-IT TESTS THE WHOLE SYSTEM --A DCG REQUIRES CATHETERIZATION OF THE CANALICULUS FOR INJECTION OF DYE
-UNLIKE THE DCG, THE TRACER IS NOT INSTILLED UNDER PRESSURE*