Lithotripsy Lens (image) Duke University Caption This lithotripsy machine shock wave lens was modified by Duke engineers to more efficiently break up kidney stones. Modifications included a groove cut around the perimeter and an alteration in geometry. Credit Duke University Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.