Gantry (IMAGE) Paul Scherrer Institute Caption Gantry 3 at the Center for Proton Therapy at PSI. With the help of this rotating treatment apparatus, cancer patients are irradiated with protons to destroy tumours. Credit Scanderbeg Sauer Photography Usage Restrictions PSI provides image and/or video material free of charge for media coverage of the content of the above text. Use of this material for other purposes is not permitted. This also includes the transfer of the image and video material into databases as well as sale by third parties. License Licensed content 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.