154results about "X-ray tube cold cathodes" patented technology

In a method and device for producing a tomosynthetic 3D x-ray image, a number of 2D projection images of an examination subject are acquired using a fixed x-ray source. The x-ray source has multiple, individually controllable emitters that respectively emit a single x-ray dose from various different directions. The tomosynthetic 3D image is reconstructed from the individual 2D projection images, and at least one 2D projection image is composed of multiple individual images.

An improved x-ray generation system produces a converging or diverging radiation pattern particularly suited for substantially cylindrical or spherical treatment devices. In an embodiment, the system comprises a closed or concave outer wall about a closed or concave inner wall. An electron emitter is situated on the inside surface of the outer wall, while a target film is situated on the outside surface of the inner wall. An extraction voltage at the emitter extracts electrons which are accelerated toward the inner wall by an acceleration voltage. Alternately, electron emission may be by thermionic means. Collisions of electrons with the target film causes x-ray emission, a substantial portion of which is directed through the inner wall into the space defined within. In an embodiment, the location of the emitter and target film are reversed, establishing a reflective rather than transmissive mode for convergent patterns and a transmissive mode for divergent patterns.

An x-ray imaging system has an x-ray source having an electron field emission source that emits an x-ray beam that strikes an elongated, stationary anode in an evacuated housing. A magnetic deflection system steers the electron beam between the electron field emission source and the anode, so that the electron beam can strike the anode at different locations, thereby causing x-rays to be emitted from those different locations, by controlling the degree of magnetic deflection. A radiation detector detects the x-rays after attenuation by an examination subject, and generates signals dependent on the detected radiation that represent an image of the subject.

A multi X-ray generating apparatus which has a plurality of electron sources arranged two-dimensionally and targets arranged at positions opposite to the electron sources includes a multi electron source which includes a plurality of electron sources and outputs electrons from driven electron sources by selectively driving a plurality of electron sources in accordance with supplied driving signals, and a target unit which includes a plurality of targets which generate X-rays in accordance with irradiation of electrons output from the multi electron source and outputs X-rays with different radiation qualities in accordance with the generation locations of X-rays. The generation locations and radiation qualities of X-rays from the target unit are controlled by selectively driving the electron sources of the multi electron source.

Medical system comprising an X-ray tube unit catheter 302 and an X-ray tube unit including a miniaturised X-ray tube 301, wherein the X-ray tube unit is adapted to be inserted into the X-ray tube unit catheter in order to generate X-ray radiation at a treatment position in a vessel within a human or animal body.The X-ray tube is provided with a distal electrical pole and a proximal electrical pole. The proximal pole is connected via an insulated electrical conductor 305 to an external power source. The distal pole is connectable to a conducting means 304 at the inner surface of the catheter wall via distal connecting means 303. The conducting means has a predetermined length extending in the longitudinal direction of the catheter and is connected via an insulated electrical conductor to the external power source. During treatment the X-ray tube unit is adapted to be moved in relation to the X-ray tube unit catheter, wherein the distal pole is electrically connected to the conducting means.

A system and method for limiting emittance growth in an electron beam is disclosed. The system includes an emitter element configured to generate an electron beam and an extraction electrode positioned adjacent to the emitter element to extract the electron beam out therefrom, the extraction electrode including an opening therethrough. The system also includes a meshed grid disposed in the opening of the extraction electrode to enhance intensity and uniformity of an electric field at a surface of the emitter element and an emittance compensation electrode (ECE) positioned adjacent to the meshed grid on the side of the meshed grid opposite that of the emitter element and configured to control emittance growth of the electron beam.

A microminiature X-ray tube with a triode structure using a nano emitter is provided, which can increase a field emission region as much as possible by means of nano emitters fine-patterned in a cathode to not only increase an emission current per unit area as much as possible but secure high electrical characteristics, reliability, and structural stability by means of a cover and a bonding material. In addition, gate holes having a macro structure can be formed in the gate to promote electron beam focusing by means of the gate without using a separate focusing electrode and to prevent a leakage current from occurring on the gate. Further, an auxiliary electrode can be formed on a top or an inner surface of a cover applied for structural stability to further promote the electron beam focusing and to control the output amounts per individual X-ray tubes output according to current switching to be equal to each other.

A planar electron emitter, based on the existence of quasi-ballistic transport of electrons is disclosed. In its preferred embodiment the planar electron emitter structure consists of a body of finite gap pure semiconductor or insulator, the said body of macroscopic thickness (˜1 mm) being terminated by two parallel surfaces and of a set of two electrodes deposited/grown on the said two free surfaces such that when a low external electrical field (˜100 V/cm) is applied to this structure, consisting of two electrodes and the said semiconductor or insulating body sandwiched between them, a large fraction of electrons injected into the said semiconductor or insulator body from the negatively charged electrode (cathode) is quasi-ballistic in nature, that is this fraction of injected electrons is accelerated within the said semiconductor or insulator body without suffering any appreciable inelastic energy losses, thereby achieving sufficient energy and appropriate momentum at the positively charged electrode (anode) to be able to traverse through the said anode and to escape from the said structure into empty space (vacuum), said semiconductor or insulator body comprises a material or material system having a predetermined crystal orientation.

In an X-ray generator which includes an electron beam generating unit which has a plurality of electron emitters and generates an electron beam corresponding to driven electron emitters, and a target electrode which generates X-rays with the irradiation position of an electron beam generated by the electron beam generating unit being an X-ray focus, the X-ray focus shape formed by a set of X-ray focuses on the target electrode is controlled by individually controlling driving of the plurality of electron emitters.