Background: Urinary tract infection (UTI) is considered one of the most common types of infection in children. Vesicoureteral reflux (VUR) is one of the major risk factors of UTI leading to renal scarring. Cur-rently, two diagnostic methods are used for the evaluation of VUR, including voiding cystourethrography (VCUG) and radionuclide cystourethrography (DRNC). The present study examines the prevalence and intensity of VUR using direct radionuclide cystography (DRNC) in children referred to the Nuclear Medi-cine Division of Imam Reza Hospital in Tabriz, Iran.
Materials and Methods: The referred patients were studied by DRNC in filling, post filling, voiding and post voiding phases if there was confirmed VUR or not. Furthermore, VCUG, sonography and urine cul-ture had been performed for all the patients prior to our investigation. Both dynamic and static imaging were performed from the bladder, ureters and kidneys. The results were studied by a nuclear medicine physician to assess VUR and grade it. 
Results: The prevalence of VUR among all 300 patients was calculated to be 29.3%. Most of the cases of VUR were unilateral (63.6%), among which involvement of the left kidney (42%) was significantly more frequent (p=0.022). The most common grade in the cases with unilateral involvement was grade B, and in those with bilateral involvement, grade C. The highest frequency of VUR was observed in the age group below 1 year (10%, n=30), followed by 1-4 years and 5-8 years, each with the frequency of 8.67% (n=26).  There was no significant difference in terms of frequency of VUR based on age (p=0.198).
Conclusion: Our study showed that there is no significant association between VUR and urine culture results, but there is significant association between sonography/clinical findings and VUR. Moreover, the results demonstrated that DRNC is more sensitive than VCUG in the detection of VUR.