#asktheexpert My son has hydronophrosis by birth. doctor told me it will cure by it self. but last year he had repeatedly urine infection which cause it effects hus kidney and the size was 7mm to 19mm. then we went for dtpa and dmsa and.we found he had scars on the left one. and the function is slow. then we met nephrologist he suggested antibiotic for five months then he stopped it. and he agained asked for dmsa test after five months. we found good result and there were no scars. again after five months we did ultrasound and again found his left one swelled it is now 18mm. and also dtpa test that showing slower than before. the surgeon suggested us come after six months with ultrasound sound and dtpa test. they give nuclear medicine while doing the scan is it safe for my son to do dtpa and dmsa again and again. he went through two dtpa and two dmsa in one year.