Abstract: According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, a high voltage power supply, and focus size control circuitry. The X-ray tube includes a cathode, an anode, and a deflector configured to deflect the electrons from the cathode. The high voltage power supply generates a tube voltage to be applied between the cathode and the anode. The focus size control circuitry controls a focus size formed in the anode by applying to the deflector a deflecting voltage of a deflecting voltage value based on a tube voltage value of the tube voltage and a predetermined size, in order to form a focus of the predetermined size in the anode during the period where the tube voltage is applied by the high voltage power supply.

Abstract: According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, a high voltage power supply, and focus size control circuitry. The X-ray tube includes a cathode, an anode, and a deflector configured to deflect the electrons from the cathode. The high voltage power supply generates a tube voltage to be applied between the cathode and the anode. The focus size control circuitry controls a focus size formed in the anode by applying to the deflector a deflecting voltage of a deflecting voltage value based on a tube voltage value of the tube voltage and a predetermined size, in order to form a focus of the predetermined size in the anode during the period where the tube voltage is applied by the high voltage power supply.

Abstract: According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, a high voltage power supply, and focus size control circuitry. The X-ray tube includes a cathode, an anode, and a deflector configured to deflect the electrons from the cathode. The high voltage power supply generates a tube voltage to be applied between the cathode and the anode. The focus size control circuitry controls a focus size formed in the anode by applying to the deflector a deflecting voltage of a deflecting voltage value based on a tube voltage value of the tube voltage and a predetermined size, in order to form a focus of the predetermined size in the anode during the period where the tube voltage is applied by the high voltage power supply.

Abstract: According to one embodiment, a medical image diagnostic apparatus includes an X-ray tube, a rotor and processing circuitry. The X-ray tube radiates an X-ray. The rotor holds the X-ray tube, and rotates together with the X-ray tube at least any of a first rotation speed used for scanning an object and a second rotation speed lower than the first rotation speed. The processing circuitry acquires information on a waiting time up to timing of exposure by the X-ray tube. The processing circuitry further controls a rotation speed of the rotor during the waiting time in accordance with the information on the waiting time.

Abstract: According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, a high voltage power supply, and focus size control circuitry. The X-ray tube includes a cathode, an anode, and a deflector configured to deflect the electrons from the cathode. The high voltage power supply generates a tube voltage to be applied between the cathode and the anode. The focus size control circuitry controls a focus size formed in the anode by applying to the deflector a deflecting voltage of a deflecting voltage value based on a tube voltage value of the tube voltage and a predetermined size, in order to form a focus of the predetermined size in the anode during the period where the tube voltage is applied by the high voltage power supply.

Abstract: According to one embodiment, a medical image diagnostic apparatus includes an X-ray tube, a rotor and processing circuitry. The X-ray tube radiates an X-ray. The rotor holds the X-ray tube, and rotates together with the X-ray tube at at least any of a first rotation speed used for scanning an object and a second rotation speed lower than the first rotation speed. The processing circuitry acquires information on a waiting time up to timing of exposure by the X-ray tube. The processing circuitry further controls a rotation speed of the rotor during the waiting time in accordance with the information on the waiting time.