Medical diagnostic imaging apparatus

1. A medical diagnostic imaging apparatus, comprising:

processing circuitry configured to

acquire a plurality of first X-ray images chronologically in a first X-ray irradiation area while adjusting an operating condition by feedback control using a statistic of a pixel value of each first X-ray image and a threshold set in advance; and

acquire, after acquiring the plurality of first X-ray images, a plurality of second X-ray images chronologically in a second X-ray irradiation area that is narrower than the first X-ray irradiation area while maintaining the adjusted operating condition adjusted at the time of acquiring an acquired first X-ray image of the plurality of first X-ray images.

2. The medical diagnostic imaging apparatus according to claim 1 , wherein the processing circuitry is further configured to adjust a display gain of an acquired second X-ray image of the plurality of second X-ray images so that a statistic of a pixel value of the acquired second X-ray image approaches the threshold set in advance.

3. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to

calculate the statistic of the pixel value of the acquired second X-ray image based on the adjusted operating condition and compare the statistic with the threshold, and

reflect a coefficient set in advance in a result of the comparison and adjust a new operating condition to cause the new operation condition to approach the adjusted operating condition, and

adjust the display gain of the acquired second X-ray image based on the result of the comparison.

4. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to compare the pixel value of the acquired first X-ray image with the pixel value of the acquired second X-ray image, and adjust the display gain of the acquired second X-ray image so that the pixel value of the acquired second X-ray image is higher than the pixel value of the acquired first X-ray image by a predetermined value.

5. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to compare the pixel value of the acquired first X-ray image with the pixel value of the acquired second X-ray image, and adjust the display gain of the acquired second X-ray image so that the pixel value of the acquired second X-ray image is lower than the pixel value of the acquired first X-ray image by a predetermined value.

6. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to perform both an adjustment of the display gain of the acquired first X-ray image and an adjustment of the display gain of the acquired second X-ray image, and the threshold in the adjustment of the display gain of the acquired second X-ray image is set to be lower than the threshold in the adjustment of the display gain of the acquired first X-ray image.

7. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to perform both an adjustment of the display gain of the acquired first X-ray image and an adjustment of the display gain of the acquired second X-ray image, and the threshold in the adjustment of the display gain of the acquired second X-ray image is set to be higher than the threshold in the adjustment of the display gain of the acquired first X-ray image.

8. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to

adjust the display gain based on a correlation between the pixel value of the acquired second X-ray image and a gradation,

set the threshold of the pixel value of the second X-ray image to be higher than the threshold of the pixel value of the acquired first X-ray image, and

obtain a ratio between the statistic of the pixel value of the acquired second X-ray image and the threshold to reflect the ratio in the correlation.

9. The medical diagnostic imaging apparatus according to claim 2 , wherein the processing circuitry is further configured to

adjust the display gain based on a correlation between the pixel value of the acquired second X-ray image and a gradation,

set the threshold of the pixel value of the acquired second X-ray image to be lower than the threshold of the pixel value of the acquired first X-ray image, and

obtain a ratio between the statistic of the pixel value of the acquired second X-ray image and the threshold to reflect the ratio in the correlation.

10. The medical diagnostic imaging apparatus according to claim 1 , wherein the processing circuitry is further configured to

receive an operation for adjusting a display gain of an acquired second X-ray image,

adjust the display gain of the acquired second X-ray image according to the operation received, and

perform control for causing a display to display the acquired second X-ray image whose display gain is adjusted.

11. The medical diagnostic imaging apparatus according to claim 10 , wherein the processing circuitry is further configured to

adjust the display gain of the acquired second X-ray image based on a correlation between a pixel value of the acquired second X-ray image and a gradation,

set the threshold of the pixel value of the acquired second X-ray image to be higher than the threshold of the pixel value of the acquired first X-ray image, and

obtain a ratio between the statistic of the pixel value of the acquired second X-ray image and the threshold to reflect the ratio in the correlation.

12. The medical diagnostic imaging apparatus according to claim 10 , wherein the processing circuitry is further configured to

adjust the display gain of the acquired second X-ray image based on a correlation between a pixel value of the acquired second X-ray image and a gradation,

set the threshold of the pixel value of the acquired second X-ray image to be lower than the threshold of the pixel value of the acquired first X-ray image, and

obtain a ratio between the statistic of the pixel value of the acquired second X-ray image and the threshold to reflect the ratio in the correlation.

13. The medical diagnostic imaging apparatus according to claim 1 , further comprising an X-ray source configured to output X-rays, and

wherein the operating condition includes at least one of a tube voltage, a tube current, and a pulse width in X-ray output by the X-ray source.

14. The medical diagnostic imaging apparatus according to claim 13 , wherein the processing circuitry is further configured to adjust the tube voltage in preference to the tube current and the pulse width in adjusting the operating condition.

15. The medical diagnostic imaging apparatus according to claim 1 , wherein the processing circuitry is further configured to generate a synthetic image of the acquired first X-ray image and the acquired second X-ray image based on a positional relation between the first X-ray irradiation area and the second X-ray irradiation area, and

perform control for causing a display to display the synthetic image each time the synthetic image is generated.

16. The medical diagnostic imaging apparatus according to claim 1 , wherein the processing circuitry is further configured to execute a filtering process for improving image quality of the plurality second X-ray images.

17. A medical diagnostic imaging apparatus, comprising:

processing circuitry configured to

capture a subject in a second X-ray irradiation area that is narrower than a first X-ray irradiation area after imaging the subject in the first X-ray irradiation area;

generate a first X-ray image in the first X-ray irradiation area and a second X-ray image in the second X-ray irradiation area based on an imaging result;

calculate a statistic of a pixel value of the first X-ray image and adjust an operating condition of the imaging the subject in the first X-ray irradiation area so that the statistic approaches a threshold set in advance;

control, after generating the first X-ray image, generating of the second X-ray image so as to generate the second X-ray image based on the adjusted operating condition; and

adjust a display gain of the second X-ray image so that the statistic of the pixel value of the second X-ray image generated approaches the threshold set in advance.

18. The medical diagnostic imaging apparatus according to claim 17 , wherein

the processing circuitry is further configured to

calculate the statistic of the pixel value of the second X-ray image generated based on the operating condition and compare the statistic with the threshold,

reflect a coefficient set in advance in a result of the comparison and adjust a new operating condition to cause the new operation condition to approach the operating condition, and

adjust the display gain of the second X-ray image based on the result of the comparison.

19. The medical diagnostic imaging apparatus according to claim 17 , wherein the processing circuitry is further configured to compare the pixel value of the first X-ray image with the pixel value of the second X-ray image, and adjust the display gain of the second X-ray image so that the pixel value of the second X-ray image is higher than the pixel value of the first X-ray image by a predetermined value.

20. The medical diagnostic imaging apparatus according to claim 17 , wherein the processing circuitry is further configured to compare the pixel value of the first X-ray image with the pixel value of the second X-ray image, and adjust the display gain of the second X-ray image so that the pixel value of the second X-ray image is lower than the pixel value of the first X-ray image by a predetermined value.