X-ray diagnostic apparatus and X-ray diagnostic method

1. An X-ray diagnostic apparatus, comprising:

an X-ray tube configured to expose an X-ray toward an object;

an X-ray detector configured to acquire two X-ray detection data sets by counting X-ray photons in at least two X-ray energy bands depending on a K absorption edge of an X-ray absorber taken into the object, the X-ray photons having transmitted to the object; and

processing circuitry configured to:

input information to specify the X-ray absorber;

set the at least two X-ray energy bands based on the input information to specify the X-ray absorber; and

generate at least one frame of X-ray image data by data processing including subtraction processing of the two X-ray detection data sets, the X-ray absorber having been depicted in the at least one frame of X-ray image data,

wherein the processing circuitry is further configured to set a boundary between the at least two X-ray energy bands to be higher than an energy at the K absorption edge by a predetermined amount.

2. An X-ray diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to set plural sets of two X-ray energy bands based on information to specify X-ray absorbers, the plural sets of two X-ray energy bands depending on K absorption edges of the X-ray absorbers, respectively.

3. An X-ray diagnostic apparatus of claim 1 , further comprising:

a storage circuit configured to store pieces of information related with X-ray absorbers, respectively, the pieces of information being used to determine sets of two X-ray energy bands depending on K absorption edges of the X-ray absorbers, respectively,

wherein the processing circuitry is further configured to obtain a piece of information from the storage circuit, the piece of information being used to determine two X-ray energy bands corresponding to the piece of information to specify the X-ray absorber.

4. An X-ray diagnostic apparatus of claim 3 ,

wherein the storage circuit is further configured to store the pieces of information for determining the sets of two X-ray energy bands, the pieces of information being further related with at least one of X-ray tube voltages, each possibly applied to the X-ray tube, and pieces of information identifying beam filters, each possibly placed in an output side of the X-ray tube; and

the processing circuitry is further configured to set the at least two X-ray energy bands based on at least one of an X-ray tube voltage and a beam filter corresponding to an exposure condition of an X-ray exposed from the X-ray tube.

5. An X-ray diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to:

set at least three X-ray energy bands including the at least two X-ray energy bands and at least one X-ray energy band other than the at least two X-ray energy bands; and

generate X-ray image data having a contrast which does not correspond to the K absorption edge, based on X-ray detection data corresponding to at least one of the at least three X-ray energy bands.

6. An X-ray diagnostic apparatus of claim 5 , wherein the processing circuitry is further configured to set at least one of first X-ray energy bands in which each X-ray energy band of the first X-ray energy bands is higher than any of the at least two X-ray energy bands and second X-ray energy bands in which each X-ray energy band of the second X-ray energy bands is lower than any of the at least two X-ray energy bands, the first X-ray energy bands and the second X-ray energy bands being included in the at least one X-ray energy band that is other than the at least two X-ray energy bands, the first X-ray energy bands having a first equal bandwidth, and the second X-ray energy bands having a second equal bandwidth.

7. An X-ray diagnostic apparatus of claim 5 , wherein the processing circuitry is further configured to combine the X-ray image data, in which the X-ray absorber has been depicted, with the X-ray image data having the contrast which does not correspond to the K absorption edge.

8. An X-ray diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to input at least one of an examination item and information to specify a contrast agent, as the information to specify the X-ray absorber.

9. An X-ray diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to:

set two sets of at least two X-ray energy bands based on information to specify two X-ray absorbers, the two sets depending on K absorption edges of the two X-ray absorbers respectively; and

generate four frames of X-ray image data corresponding to at least the two sets of the two X-ray energy bands.

10. An X-ray diagnostic method, comprising:

inputting information to specify an X-ray absorber taken into an object;

setting at least two X-ray energy bands based on the input information to specify the X-ray absorber, the at least two X-ray energy bands depending on a K absorption edge of the X-ray absorber;

exposing an X-ray toward the object;

acquiring two X-ray detection data sets by counting X-ray photons in the at least two X-ray energy bands, the X-ray photons having transmitted to the object; and

generating at least one frame of X-ray image data by data processing including subtraction processing of the two X-ray detection data sets, the X-ray absorber having been depicted in the at least one frame of X-ray image data,

wherein the setting step further includes setting a boundary between the at least two X-ray energy bands to be higher than an energy at the K absorption edge by a predetermined amount.