Toshiba Medical Systems Corporation

Daizo Oikawa

Hiroaki Nakai

Tooru Kato

Fumio Ishiyama

An X-ray computed tomography apparatus according to an embodiment stores a plurality of reference count data indicative of energy spectra of X-rays, which are associated with a plurality of tube voltages or tube currents. Estimation circuitry estimates a tube voltage or a tube current at a time of X-ray irradiation, based on a comparison of energy spectra between second count data and each of the plurality of reference count data. Correction circuitry corrects first count data acquired together with the second count data, by using an energy spectrum calculated based on the estimated tube voltage or tube current. Reconstruction circuitry reconstructs medical image data, based on the corrected first count data.

X-ray computed tomography apparatus including a first X-ray detector and a second X-ray detector for counting X-ray photons

X-ray CT apparatus is provided in which the photon energy distribution of X-rays to be radiated is flattened. X-ray CT apparatus includes an X-ray tube, a detector, a data acquisition system, a tube voltage generator, and a grid controller. The X-ray tube radiates X-rays onto a subject. The detector includes multiple detection elements for detecting photons forming the X-rays. The data acquisition system counts the number of the detected photons to acquire projection data based on the counted photons. The tube voltage generator applies the tube voltage to the X-ray tube while changing the tube voltage of the X-ray tube in a predetermined cycle. A tube current controller decreases the tube current upon an increase in the tube voltage, and increases the tube current upon a decrease in the tube voltage. Thus, the photon energy distribution of the X-rays radiated from the X-ray tube is flattened.

X-ray CT apparatus

An X-ray CT apparatus according to an embodiment includes acquiring circuitry and processing circuitry. The acquiring circuitry is configured to count photons derived from X-rays that have passed through a subject and to acquire a result obtained by discriminating energy levels of the counted photons as a counting result. The processing circuitry is configured to notify the acquiring circuitry of an energy dividing set that is set in accordance with an X-ray absorption characteristic of a substance designated by an operator, to receive the counting result acquired by the acquiring circuitry by allocating a counted value to each of a plurality of energy discrimination regions that are set in the energy dividing set, and to reconstruct image data by using the received counting result.

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Otawara, Japan

Daizo Oikawa