X-ray CT and medical diagnostic apparatus with photon counting detector

A medical image diagnostic apparatus comprising:

• a detector includes a plurality of detection elements including a plurality of types of detection elements with different response characteristics to an X-ray radiation dose, the plurality of types of detection elements being arranged in the detector randomly, without forming a regularly-ordered pattern of the plurality of types of detection elements in the detector, and configured to output a detection signal according to an incidence of X-ray radiation photons to each of the detection elements;
• counted result collecting circuitry configured to collect counted results obtained by counting the X-ray radiation photons from detection signals output by the detection elements;
• count rate calculating circuitry configured to calculate a count rate from the detection signals output by the detection elements;
• control circuitry configured to select a detection element based on the count rate and respective response characteristics of the detection elements;
• and
• image reconstruction circuitry configured to reconstruct medical image data using the counted result obtained from the detection element selected by the control circuitry.