The work is a prospective study which include sixty patients complaining from upper urinary tract stones (Renal and Upper ureter) measuring between 5 to 20 mm, presented to the urology department in Heliopolis Hospital in the period from December 2010 to February 2012. To all the patients history were taken, BMI were measured, Full laboratory evaluation and radiological examination were done All The patient were scanned with a multidetector row helical CT scanner (HiSpeed Dual , GE medical systems, Milwaukee, USA), and the images were obtained using high quality mode at 200 mA , 120 KV and 5mm collimation reconstructed at 3mm. to measure Stone density in Hounsfield Unit (HU), stone site and Stone size (which was defined as the greatest length in any dimension). All the patients were treated by extracorporeal shock wave lithotripsy (ESWL) using an electromagnetic lithotripter Doli S (Dornier MedTech, Germering, Germany). Where the stone were fragmented under fluoroscopic guidance by a single operator, during each session a constant number of shocks (3000 Shocks) were delivered to a maximal power of 22-24 KV at 120 shocks/min.