LASER CATHETER ULTRASONIC IMAGING SYSTEM

THE GOAL OF THIS PROJECT IS TO DEVELOP A PROTOTYPE CATHETER-MOUNTED ULTRASONIC TRANSDUCER THAT COULD BE USED TODIRECT LASER SURGERY PROCEDURES THAT USE LIGHT DELIVERED THROUGH FIBEROPTIC CATHETERS. LASER SURGERY ALLOWS PRECISE ABLATION OF LESIONS SUCH AS TUMORS, ATHEROSCLEROTIC PLAQUES, AND VASCULAR MALFORMATIONS AT SITES THAT ARE INACESSIBLE BY OTHER TECHNIQUES. HOWEVER, IT IS ALSO RELATIVELY EASY TO DAMAGE NORMAL TISSUES ADJACENT TO OR UNDERLYING THE LESIONS, OR TO CAUSE PERFORATIONS IN HOLLOW STRUCTURES. THESE COMPLICATIONS MIGHT BE AVOIDED WITH IN SITU DIAGNOSTIC INFORMATION ABOUT THE CHARACTER AND THICKNESS OF THE TARGET TISSUES AND THE EXTENT OF THERMAL DENATURATION CAUSED BY THE LASER ENERGY. ULTRASONIC IMAGING, EVEN WHEN SIMPLE AND ONE-DIMENSIONAL, IS MORE LIKELY TO PROVIDE THIS INFORMATION THAN ARE OPTICAL OR RADIOLOGICAL TECHNIQUES. THE SPECIFIC AIMS OF THIS PHASE I PROPOSAL ARE TO CONSTRUCT AND EVALUATE A MINIATURE ULTRASONIC TRANSDUCER WITH A RESOLUTION OF 1 CM THATCOULD BE COMBINED WITH A SIDE-EMITTING OPTICAL FIBER TO DETERMINE LESION THICKNESS AND TO CONTROL ABLATION. THE TRANSDUCER WILL BE TESTED IN MODEL SYSTEMS AND IN ANIMAL ANDHUMAN TISSUES IN VITRO.