Abstract:
The present invention relates to miniaturized x-ray tubes, that enable radiation treatment by locating the x-ray source within a human body in close vicinity to or inside of the area to be treated with X-rays. Advantageously, the present invention eliminates most of the problems related to the methods based on a radioactive source and offers a method for efficient and controllable radiation treatment.
Abstract:
An X-ray tube has an anode and a photocathode inside a vacuum envelope and an electron multiplier is disposed between them. Such an electron multiplier may be a plurality of sequentially disposed dynodes or a microchannel plate. Because of the secondary electron emission from the electron multiplier, a higher-power radiation is obtained without requiring a high optical power level to generate photoelectrons. The vacuum envelope may be of a rotary type with the anode and photocathode having annular regions.
Abstract:
An apparatus provides in-situ radiation treating utilizing a miniature energy transducer to produce x-rays, wherein the energy transducer includes a Schottky cathode tip. More specifically, the energy transducer includes a transducer body, an anode provided at a first end of the transducer body, and a cathode provided at a second end of the transducer body opposite the anode. The energy transducer is coupled to an energy source by a flexible insertion device. The energy source provides electrical and/or light signals to the energy transducer via the flexible insertion device. Light transmitted from the energy source to the energy transducer by the flexible insertion device is focused on a Schottky cathode tip of the cathode by the optical fiber provided in the hollow core of the anode. The application of the light signal to the cathode tip results in heating of the tip and along with the electric field generated by the acceleration voltage it leads to electron Schottky emission and electron acceleration towards the anode. In another preferred embodiment, an electrical current, transmitted from the energy source to the energy transducer by the flexible insertion device, is applied to the Schottky cathode tip of the cathode, causing thermo-emission. The electrons generated due to this process are accelerated towards the anode across a voltage difference between the anode and the cathode.
Abstract:
This invention is directed to an x-ray source comprising a housing, an elongated tubular probe, a target assembly, and a beam steering assembly. The housing encloses an electron beam source, and has elements for generating an electron beam along a beam path. The elongated tubular probe extends along a central axis from the housing about the beam path. The target assembly extends along the central axis and is adapted for coupling to the end of the probe distal form the housing. The target assembly includes a target element positioned along the beam path, wherein the target element is adapted to emit x-rays in a predetermined spectral range in response to incident electrons. The beam steering assembly includes a deflection element, a feedback network, and a deflection controller. The deflection element deflects the beam from a nominal axis to a selected surface region on the target element in response to a deflection control signal. The feedback network includes deflection sensing elements for sensing the deflection of the beam and elements for generating a feedback signal representative thereof. The deflection controller couples to the deflection element and to the feedback network and includes elements for generating a deflection control signal in response to the feedback signal.