Method for calculating elastic modulus and device for calculating elastic modulus
An elastic modulus of a viscoelastic body can be calculated with a high spatial resolution and in a relatively short measurement time. A projection image of an X-ray is detected with a detection unit by vibrating an object while maintaining a relative positional relationship between a first diffraction grating and a second diffraction grating. Then, an elastic modulus of the object is calculated based on a displacement amount of a wave due to the vibration in the projection image of the X-ray detected by the detection unit.
1 . A method for calculating an elastic modulus using a phase contrast X-ray optical system capable of detecting refraction or scattering of X-rays by an object, the phase contrast X-ray optical system including a grating portion, a radiation source configured to irradiate the grating portion and the object with X-rays, and a detection unit that detects the X-rays having passed through the grating portion and the object for each pixel, the grating portion including a first diffraction grating and a second diffraction grating disposed in parallel with a self-image of the first diffraction grating, and a relative positional relationship between the first diffraction grating and the second diffraction grating being set so as to be at or near a position at which an X-ray intensity of each pixel becomes an average value, the method comprising:
detecting a projection image of the X-rays with the detection unit by causing vibration in the object without performing fringe scanning and without performing phase retrieval, while maintaining the relative positional relationship between the first diffraction grating and the second diffraction grating; and
calculating an elastic modulus of the object based on a displacement amount of a wave due to the vibration in the projection image of the X-rays detected by the detection unit,
wherein the projection image is formed by the X-rays having passed through the grating portion, and
wherein the displacement amount of the wave is tracked from a spatial displacement of a structural contrast included in the projection image without separating the structural contrast into components of absorption, refraction, and scattering.
2 . The method for calculating the elastic modulus according to claim 1 , wherein the object is a living tissue.
3 . The method for calculating the elastic modulus according to claim 1 , wherein the displacement amount of the wave is tracked from a spatial displacement of a structural contrast included in the projection image without performing quantitative X-ray imaging.
4 . A device for calculating an elastic modulus, comprising:
a phase contrast X-ray optical system capable of detecting refraction or scattering of X-rays by an object;
a vibration unit configured to vibrate the object; and
a processing unit,
the phase contrast X-ray optical system including:
a grating portion,
a radiation source configured to irradiate the grating portion and the object with X-rays, and
a detection unit configured to detect the X-rays having passed through the grating portion and the object for each pixel,
wherein the grating portion includes a first diffraction grating and a second diffraction grating disposed in parallel with a self-image of the first diffraction grating,
wherein a relative positional relationship between the first diffraction grating and the second diffraction grating is maintained at or near a position at which an X-ray intensity of each pixel becomes an average value,
wherein the vibration unit is configured to excite the object so as to cause vibration in the object,
wherein the detection unit is configured to detect a projection image of the X-rays while the vibration unit vibrates the object without performing fringe scanning and without performing phase retrieval,
wherein the processing unit is configured to calculate an elastic modulus of the object based on a displacement amount of a wave due to the vibration in a projection image of the X-rays detected by the detection unit,
wherein the projection image is formed by the X-rays having passed through the grating portion, and
wherein the displacement amount of the wave is tracked from a spatial displacement of a structural contrast included in the projection image without separating the structural contrast into components of absorption, refraction, and scattering.
5 . The device for calculating the elastic modulus according to claim 4 , wherein the displacement amount of the wave is tracked from a spatial displacement of a structural contrast included in the projection image without performing quantitative X-ray imaging.