Ultraslow SWL Versus Slow SWL for Renal Stones With High Attenuation Value

Inclusion Criteria: * single Renal stone less than or equal to 3 cm (2 cm for lower calyceal stones) * radio-opaque stone * high attenuation value (≥ 1000 HU) stone Exclusion Criteria: * Abnormal renal anatomy * renal insufficiency * solitary kidney * coagulopathies * uncontrolled hypertension * renal artery or aortic aneurysm * active urinary tract infection * pregnancy * severe skeletal malformations (spinal deformity) precluding proper stone localization * skin to stone distance (SSD) \> 11 cm * BMI \> 30 Kgm/m2