Abstract

Laser catheter delivery system for controlled ablation of atheroma, combining laser angioplasty and intra-arterial ultrasonic imaging. In laser ablation of atheroma, dosage and directing of the laser light beam represent critical problems, since accurate removal of the atheroma is required without damaging of the arterial wall. The present system comprise a combined laser and ultrasound catheter composed ofapparatus for emitting a laser beam in an artery towards an atheroma for ablation of the atheromaan optical fiber assembly for feeding laser light from a laser to the emitting apparatusan ultrasound transducer for intra-arterial imaging of tissue structures like the atheroma, the vessel wall and surrounding tissue, by emitting a pulsed ultrasound beam towards the tissue structures and also arranged to receive backscattered ultrasound from the tissue structuresbeam directing apparatus arranged to direct the ultrasound beam towards the tissue structures and also arranged so that the laser beam can be brought into for practical purposes any of the directions the ultrasound beam can assume for imaging, so that the laser beam can be steered towards a portion of the ultrasound image indicating a portion of an atheroma to ablate that portion of the atheromareceive circuits adapted to receive and process the backscattered ultrasound for imaging of the tissue structures, andapparatus for analysing the ultrasound image, either manually or automatically, to determine the presence of atheroma so that the image can be used to direct the laser beam towards the regions in the ultrasound image which have been determined to represent a portion of an atheroma and determine the intensity and the dosage of the laser beam for accurate ablation of that portion of the atheroma.