Real-time target tracking applied to improve fragmentation of renal stones in extra-corporeal lithotripsy

Abstract

In extra-corporeal shock wave lithotripsy (ESWL), focused acoustic waves are used to fragment urinary stones. The success of the treatment depends on coincidence between the stone position and the point of convergence of the waves. However, the stone may move during the treatment. We developed a software called Echotrack which performs a real-time tracking of the stone in ultrasound images and automatically adjusts the position of the generator of shock waves. Clinical tests carried out in 65 patients showed that the Echotrack is able to track the stones as long as they are visible in the images. The number of shocks necessary to fragment the stones is reduced by 40%.