Abstract: An X-ray tube includes an evacuated envelope; a cold cathode mounted at one end of the envelope and capable of field emission of electrons when subjected to a high electrostatic field; and an anode mounted at the opposite end of the envelope coaxial with and axially spaced from the cathode, and capable of emitting X-rays when struck by electrons emitted by the cathode. The envelope includes an end wall made of thermally-conductive and electrically-insulating material in contact with the anode and formed with a fluid cooling channel to remove the heat generated at the anode. In one described embodiment, the cathode includes a body of a getter material which is both electron emissive and gas absorptive. In other described embodiments, the cathode includes a carbon nanotube field-emission electron source.

Abstract: A device for delivering radiation to at least one preselected site in a vascular system of a patient, includes an elongated flexible catheter tube of a diameter for insertion into the patient's vascular system, and a flexible guide wire within the catheter tube and movable along its length. The guide wire includes a proximal end to be located externally of the patient's vascular system for moving the guide wire within the catheter tube, and a rounded distal tip at the opposite end to facilitate movement of the guide wire through the catheter tube. At least one radiation-producing element is fixed to the guide wire at an intermediate location spaced from the rounded distal tip.