According to one embodiment, Switching units are configured to switch the intensity of X-rays to be generated by an anode. An X-ray controller controls the switching units to switch the intensity of the X-rays to be generated by the anode, and controls a rotor control power generator to rotate the anode. When a value approximately equal to an integer multiple of an X-ray intensity switching period designated by a user coincides with the rotor rotation period, the X-ray controller controls the rotor control power generator to shift the thermoelectron collision ranges of the anode in the first turn from thermoelectron collision ranges in the second turn.

According to one embodiment, Switching units are configured to switch the intensity of X-rays to be generated by an anode. An X-ray controller controls the switching units to switch the intensity of the X-rays to be generated by the anode, and controls a rotor control power generator to rotate the anode. When a value approximately equal to an integer multiple of an X-ray intensity switching period designated by a user coincides with the rotor rotation period, the X-ray controller controls the rotor control power generator to shift the thermoelectron collision ranges of the anode in the first turn from thermoelectron collision ranges in the second turn.

Systems and methods for digitally switching x-ray emission systems include a digital switching unit operable to selectively connect a low voltage driving circuit to activate a field emission type electron emitting construct such that electrons are accelerated by a high voltage towards an anode target thereby generating a pulse of x-rays. The x-ray pulses directed towards a scintillator are detected by an optical imager when its shutter is open. Shutter signals and the activation signals may be synchronized to produce required x-ray detection profiles.

A computer tomography x-ray tube for generating pulsed x-rays is presented. The x-ray tube comprises an anode and an electron emission unit for generating a pulsed electron beam onto the anode. Furthermore, a rotation mechanism for rotating the anode characterized in that the rotation mechanism is configured for rotating the anode with an angular velocity that varies in time is comprised. The rotation mechanism may also be configured for rotating the anode such that the variation of the angular velocity in time is a continuous oscillation around a mean angular velocity ω.sub.0 in time. In a preferred embodiment the angular velocity ω (t) varies in time according to the following formula:

ω(t)=ω.sub.0+Δω sin Ωt,

wherein ω.sub.0 is a mean angular velocity. In a particular embodiment, the grid switch for generating the pulsed electron beam is comprised and the x-ray tube may be embodied as a stereo tube, in which two focal spots of electron beams are generated in an alternating manner.

A computer tomography x-ray tube for generating pulsed x-rays is presented. The x-ray tube comprises an anode and an electron emission unit for generating a pulsed electron beam onto the anode. Furthermore, a rotation mechanism for rotating the anode characterized in that the rotation mechanism is configured for rotating the anode with an angular velocity that varies in time is comprised. The rotation mechanism may also be configured for rotating the anode such that the variation of the angular velocity in time is a continuous oscillation around a mean angular velocity ω.sub.0 in time. In a preferred embodiment the angular velocity ω (t) varies in time according to the following formula:

ω(t)=ω.sub.0+Δω sin Ωt,

wherein ω.sub.0 is a mean angular velocity. In a particular embodiment, the grid switch for generating the pulsed electron beam is comprised and the x-ray tube may be embodied as a stereo tube, in which two focal spots of electron beams are generated in an alternating manner.

An X-ray CT apparatus and an image reconstruction method are configured (i) to determine a movement phase to be used for generating diagnostic images with a small number of operations and (ii) to acquire diagnostic images in a short time while reducing a burden on an operator, such as when the target in scanning is a moving site. For example, an image processing device of an X-ray CT apparatus obtains movement information of a diagnostic site (such as the heart), determines phase selection positions, permits the operator to select an arbitrary movement phase based on the acquired movement information, and reconstructs selection images in a plurality of movement phases for each of the determined phase selection positions using scan data before presentation.

An X-ray CT apparatus and an image reconstruction method are configured (i) to determine a movement phase to be used for generating diagnostic images with a small number of operations and (ii) to acquire diagnostic images in a short time while reducing a burden on an operator, such as when the target in scanning is a moving site. For example, an image processing device of an X-ray CT apparatus obtains movement information of a diagnostic site (such as the heart), determines phase selection positions, permits the operator to select an arbitrary movement phase based on the acquired movement information, and reconstructs selection images in a plurality of movement phases for each of the determined phase selection positions using scan data before presentation.

Provided herein is a radiography apparatus including an X-ray source configured to irradiate a subject radiation, and a sensing module configured to sense the radiation having passed through the subject, wherein the X-ray source includes a cathode electrode comprising an electric field emitting source configured to emit electrons, an anode electrode disposed opposite to the cathode electrode and configured to use the electrons to generate the radiation, and a current control unit connected to the cathode electrode to control an amount of the electrons.

Motion correction is performed in time-of-flight (TOF) positron emission tomography (PET). Rather than applying motion correction to reconstructed images or as part of reconstruction, the motion correction is applied in the projection domain of the PET data. The TOF data from the PET scan is altered to account for the motion. The TOF data is altered prior to starting reconstruction. The motion in the patient or image domain is forward projected to provide motion in the projection domain of the TOF data. The projected motion of different phases is applied to the TOF data from different phases, respectively, to create a combined dataset of motion corrected TOF data representing the patient at a reference phase. The dataset is larger (e.g., similar size from projection data dimension point of view, but contains more counts per projection data unit or is more dense) than available at one phase of the physiological cycle and is then used in reconstruction.

Disclosed herein are representative embodiments of methods, apparatus, and systems for performing radiography. For example, certain embodiments concern X-ray radiography of spontaneous events. Particular embodiments of the disclosed technology provide continuous high-speed x-ray imaging of spontaneous dynamic events, such as explosions, reaction-front propagation, and even material failure. Further, in certain embodiments, x-ray activation and data collection activation are triggered by the object itself that is under observation (e.g., triggered by a change of state detected by one or more sensors monitoring the object itself).