Patent Number: 
Section: claims

1. An X-ray diagnostic apparatus, comprising:an X-ray tube configured to radiate X-rays;an X-ray collimator configured to change an irradiation region of the X-rays radiated by the X-ray tube;an X-ray detector that includes a first detector and a second detector having a smaller detection area than a detection area of the first detector, and is configured to be able to detect the X-rays radiated to a fixed irradiation region, after being changed by the X-ray collimator, with the first detector and the second detector at the same time by arranging the first detector and the second detector so as to overlap in an irradiation direction of the X-rays and detecting the X-rays radiated to an overlapping region where the first detector and the second detector overlap with each other; andprocessing circuitry configured togenerate a synthesized image obtained by synthesizing a first X-ray image generated based on an output from the first detector in the fixed irradiation region, and a second X-ray image generated based on an output from the second detector in the fixed irradiation region, the synthesized image having an image size corresponding to an aspect ratio of the fixed irradiation region, andcause a display to display the synthesized image. 2. The X-ray diagnostic apparatus according to claim 1, wherein the processing circuitry is configured todetermine a side serving as a reference of the image size of the synthesized image in accordance with the aspect ratio of the fixed irradiation region, andgenerate the synthesized image obtained by synthesizing the first X-ray image and the second X-ray image with an image size corresponding to a length of the determined side. 3. The X-ray diagnostic apparatus according to claim 2, wherein the processing circuitry is configured to determine a long side of the fixed irradiation region to be a side serving as a reference of the image size. 4. The X-ray diagnostic apparatus according to claim 2, wherein the processing circuitry is configured to generate the synthesized image obtained by synthesizing the first X-ray image and the second X-ray image so that the length of the side serving as a reference of the image size of the synthesized image is matched with a length of a corresponding side of a display region of the synthesized image on the display. 5. The display method according to claim 2, comprising:generating the synthesized image obtained by synthesizing the first X-ray image and the second X-ray image so that the length of the side serving as a reference of the image size of the synthesized image is matched with a length of a corresponding side of a display region of the synthesized image on the display. 6. The X-ray diagnostic apparatus according to claim 1, wherein the second detector has a pixel size smaller than that of the first detector. 7. The X-ray diagnostic apparatus according to claim 1, wherein the processing circuitry is configured to sequentially acquire the first X-ray image and the second X-ray image, and sequentially generate the synthesized image based on the acquired first X-ray image and the acquired second X-ray image. 8. The display method according to claim 1, wherein the second detector has a pixel size smaller than that of the first detector. 9. The display method according to claim 1, comprising sequentially acquiring the first X-ray image and the second X-ray image, and sequentially generating the synthesized image based on the acquired first X-ray image and the acquired second X-ray image. 10. An X-ray diagnostic apparatus, comprising:an X-ray tube configured to radiate X-rays;an X-ray collimator configured to change an irradiation region of the X-rays radiated by the X-ray tube;an X-ray detector that includes a first detector and a second detector having a smaller detection area than a detection area of the first detector, and is configured to be able to detect the X-rays radiated to a fixed irradiation region, after being changed by the X-ray collimator, with the first detector and the second detector at the same time by arranging the first detector and the second detector so as to overlap in an irradiation direction of the X-rays and detecting the X-rays radiated to an overlapping region where the first detector and the second detector overlap with each other: andprocessing circuitry configured togenerate a synthesized image obtained by synthesizing a first X-ray image generated based on an output from the first detector in the fixed irradiation region, and a second X-ray image generated based on an output from the second detector in the fixed irradiation region, andcause a display to display the synthesized image, whereinthe processing circuitry is configured tochange a size of a display region of the synthesized image on the display in accordance with the fixed irradiation region, andcause the synthesized image to be displayed in the changed display region. 11. The X-ray diagnostic apparatus according to claim 10, wherein the processing circuitry is configured tochange at least one of a size and a position of the display region for displaying a display target other than the synthesized image on the display to change the size of the display region of the synthesized image, andcause the synthesized image to be displayed in the changed display region. 12. The X-ray diagnostic apparatus according to claim 10, wherein the processing circuitry is configured to change a size of the display region so that a size of an image obtained by the second detector is kept to be substantially constant on the display. 13. The X-ray diagnostic apparatus according to claim 10, wherein the second detector has a pixel size smaller than that of the first detector. 14. The X-ray diagnostic apparatus according to claim 10, wherein the processing circuitry is configured to sequentially acquire the first X-ray image and the second X-ray image, and sequentially generate the synthesized image based on the acquired first X-ray image and the acquired second X-ray image. 15. A display method for displaying an X-ray image generated based on an output from an X-ray detector that includes a first detector and a second detector having a smaller detection area than a detection area of the first detector, and is configured to be able to detect X-rays radiated to a fixed irradiation region, after being changed by an X-ray collimator for changing an irradiation region of the X-rays radiated by an X-ray tube, with the first detector and the second detector at the same time by arranging the first detector and the second detector so as to overlap in an irradiation direction of the X-rays and detecting the X- rays radiated to an overlapping region where the first detector and the second detector overlap with each other, the display method comprising:generating a synthesized image obtained by synthesizing a first X-ray image generated based on an output from the first detector in the fixed irradiation region, and a second X-ray image generated based on an output from the second detector in the fixed irradiation region, the synthesized image having an image size corresponding to an aspect ratio of the fixed irradiation region, anddisplaying the synthesized image on a display. 16. The display method according to claim 15, comprising:determining a side serving as a reference of the image size of the synthesized image in accordance with the aspect ratio of the fixed irradiation region, andgenerating the synthesized image obtained by synthesizing the first X-ray image and the second X-ray image with an image size corresponding to a length of the determined side. 17. The display method according to claim 16, comprising determining a long side of the fixed irradiation region to be a side serving as a reference of the image size.