The disclosure relates to a device for use in removing undesired material from a duct within a patient's body. The device comprises a catheter adapted to be disposed within a duct and an element disposed adjacent to the distal end portion of the catheter such as a fiber optic emitting laser energy, a heated element or a knife for intersecting and releasing the undesired material. The undesired material may be an occlusion or an accumulation of plaque within a blood vessel. An inflatable bladder is provided for positioning the distal end portion of the catheter adjacent the inner surface of the duct to maintain the element for intersecting and releasing the undesired material adjacent thereto. The device can also include a pair of abutments disposed adjacent the distal end portion of the catheter to form a chamber adjacent the inner surface of the blood vessel and prevent the escape of laser energy after it has been applied to the undesired material.