Purpose: Conventional contrast dacryocystography(C-DCG) has been used mainly for anatomical assessment of thelacrimal drainage apparatus, due to its limited information on the dynamics of the lacrimal system, and thuscorrelation role in epiphora. The purpose of study was to improve the diagnostic value in epiphora by utilizing RIdacryocystography(RI-DCG) with quantitative criteria. Materials and Methods: The patient for RI dacryocystographyset erect with the head fixed in front of gamma camera fitted with a standard 6 mm pinhole collimater. Both eyesof 85 patients(170 eyes) were scanned with 99mTc-pertechnetate followed by conventional dacryocystography. Thedata from gamma camera were recorded simultaneously on a computer system for subsequent quantitative analysis.Results: In 94 of 96 eyes without epiphora, RI-DCG was correlated with normal C-DCG and % of emptying was at leastover 50%. In 58 of 74 eyes 0with epiphora, RI-DCG was correlated with abnormal C-DCG and % of emptying was at mostbelow 50%. In 16 eyes with functional block, quantitative RI-DCG showed abnormal % of emptying. Conclusion:Nuclear DCG with quantitation had higher diagnostic yield in functional block and correlated higher with epiphora.Thus nuclear DCG with quantitation would be a valuable functional test after postprocedures such asdacryocystoplasty.