An x-ray micro-beam radiation production system is provided having: a source of accelerated electrons, an electron focusing component configured to focus the electrons provided by the source, and a target which produces x-rays when electrons impinge thereon from the source. The electron focusing component is configured to focus the electrons provided by the source such that they impinge at a focal spot having a width δ formed on a surface of the target. The focusing component is configured to move the electron beam relative to the target such that the focal spot moves across the target surface in the width direction, and/or the target is movable relative to the focusing component such that the focal spot moves across the target surface in the width direction, the surface velocity of the focal spot across the target surface in the width direction being greater than v.sub.t where:formula (I), k, ρ and c denoting respectively the heat conductivity, the density and the heat capacity of the target material, and d denoting the electron penetration depth in the target material. $v_t=\frac{\pi k}{4\rho c}.Math.\frac{\delta }{d^2},$

An x-ray micro-beam radiation production system is provided having: a source of accelerated electrons, an electron focusing component configured to focus the electrons provided by the source, and a target which produces x-rays when electrons impinge thereon from the source. The electron focusing component is configured to focus the electrons provided by the source such that they impinge at a focal spot having a width δ formed on a surface of the target. The focusing component is configured to move the electron beam relative to the target such that the focal spot moves across the target surface in the width direction, and/or the target is movable relative to the focusing component such that the focal spot moves across the target surface in the width direction, the surface velocity of the focal spot across the target surface in the width direction being greater than v.sub.t where:formula (I), k, ρ and c denoting respectively the heat conductivity, the density and the heat capacity of the target material, and d denoting the electron penetration depth in the target material. $v_t=\frac{\pi k}{4\rho c}.Math.\frac{\delta }{d^2},$

A bearing device includes a rotational shaft; a first outer ring; a second outer ring; first balls; second balls disposed; and a C-spacer and a second spacer. α>δd is satisfied, where δd represents a difference between an inside diameter of the second spacer at an end portion on a second side and an outside diameter of a shaft outer circumferential face, and α represents a half of a difference between a diameter of a cylindrical face of the C-spacer on an outer circumferential side and a diameter of the cylindrical face of the C-spacer on an inner circumferential side.

Described are devices, systems, and methods for modulating the spectral energy distribution produced by an x-ray source via control of the energy of the x-ray-generating electron beam, e.g., for energy-modulated radiation therapy or other purposes. In some embodiments, such energy modulation is achieved by an add-on device to a linear accelerator. Also disclosed are computational methods and computer program products for planning energy-modulated therapy.

Described are devices, systems, and methods for modulating the spectral energy distribution produced by an x-ray source via control of the energy of the x-ray-generating electron beam, e.g., for energy-modulated radiation therapy or other purposes. In some embodiments, such energy modulation is achieved by an add-on device to a linear accelerator. Also disclosed are computational methods and computer program products for planning energy-modulated therapy.

According to one embodiment, a sliding bearing unit includes a stationary shaft including a first radial bearing surface, a rotor, and a lubricant. The rotor includes a first cylinder and a second cylinder. The second cylinder includes a second radial bearing surface and is restricted in operation so that it does not rotate relative to the first cylinder. The lubricant, together with the first radial bearing surface and the second radial bearing surface, forms a dynamic pressure radial sliding bearing.

An x-ray emitter includes an x-ray tube and an x-ray emitter housing. In an embodiment, the x-ray tube includes an evacuated x-ray tube housing, a cathode for emitting electrons and an anode for generating x-rays as a function of the electrons. Further, in an embodiment, the x-ray emitter housing includes the x-ray tube and outside of the x-ray tube, a gaseous cooling medium. In an embodiment, the x-ray emitter further includes a compressor for a forced convection of the gaseous cooling medium for cooling the x-ray tube, a pressure ratio between the intake side and pressure side of the compressor being greater than 1.3.

Provided is an X-ray imaging system capable of performing X-ray imaging quickly. The X-ray imaging system is provided with: an X-ray tube device including a cathode and an anode, the X-ray tube device being capable of performing X-ray imaging by irradiating an imaging target with X-rays in a state of rotating the anode; a light irradiation device including a collimator defining an X-ray irradiation range of the X-rays with respect to the imaging target, a visible light irradiation unit for emitting visible light to the imaging target and a light irradiation operation unit for performing an operation for making the visible light irradiation unit in the light irradiation state; and a controller for controlling operations of the X-ray tube device and the light irradiation device. The controller rotates the anode at an imaging possible rotation speed capable of performing X-ray imaging when the light irradiation operation unit is operated.

The X-ray imaging apparatus includes: a main power supply operation unit for switching ON/OFF of power supply to the X-ray imaging apparatus; a braking unit for decelerating a rotation speed of the anode to a predetermined braking speed lower than a resonance range which is a rotation speed of the anode at which resonance occurs in the X-ray tube; and a non-braking stop prediction unit configured to detect a predetermined situation in which a non-braking stop state is predicted, the non-braking stop state being a state in which the main power supply operation unit is operated to be turned to an OFF state without decelerating the rotating anode by the braking unit. The non-braking stop prediction unit activates the braking unit by detecting the predetermined situation to decrease the rotation speed of the anode to the braking speed.

An X-ray tube device capable of preventing a holder holding a bearing from suffering damage, and an X-ray CT apparatus including the X-ray tube device are provided. The X-ray tube device includes: a cathode that produces an electron beam; an anode that produces X rays upon irradiation with the electron beam; a rotating portion that supports and rotates the anode; bearings that are placed at a predetermined distance from each other in a direction of a rotation axis of the rotating portion, each of the bearings having an outer ring and an inner ring between which rolling elements are sandwiched; and a holder that holds the outer rings. The holder has an inner wall that is spaced from an edge of the outer ring.