Experimental research on the feature of an x-ray Talbot–Lau interferometer versus tube accelerating voltage

Abstract

X-ray Talbot-Lau interferometer has been used most widely to perform X-ray phasecontrast imaging with a conventional low-brilliance X-ray source, it yields high-sensitivity phase and dark-field images of sample producing low absorption contrast, thus bearing tremendous potential for future clinical diagnosis. In this manuscript, while changing accelerating voltage of the X-ray tube from 35KV to 45KV, X-ray phase-contrast imaging of a test sample were performed at each integer KV position to investigate the characteristic of an X-ray Talbot-Lau interferometer (located in the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Japan) vs. tube voltage. Experimental results and data analysis show that this X-ray Talbot-Lau interferometer is insensitive to the tube accelerating voltage within a certain range, fringe visibility around 44% is maintained in the aforementioned tube voltage range. This experimental research implies that potential new dual energy phase-contrast X-ray imaging strategy and rough refraction spectrum measurement is feasible with this X-ray Talbot-Lau interferometer.

Preliminary demonstration of flexible dual-energy x-ray phase-contrast imaging

“…Finally, we want to point out that, when choosing the high tube voltage for the dual-energy imaging in our experiment, 70 kV or 80 kV was not used, the reason is that the Au height of our absorption gratings is only 50 μm, the visibility of the moiré fringe would be unacceptable for retrieving the refractive image when our absorption gratings work in such high X-ray tube voltages, because the absorption of the Au grating would be lower when increasing the photon energy. Note that in our experiments, the visibility of the moiré fringe was 16% and 6% when the X-ray tube was operated respectively at 40 kV and 50 kV (this fact can also explain why Accepted by Optical Engineering 14 the deviations between the experiment value and the fitted one in Fig. 5(C) and Fig.…”

“…In equations ( 1) and ( 2), 14,23 I and 0 I are the photon intensities of the X-ray beam with and without the sample, respectively,  is the mean wavelength of the energy spectrum (here 27 keV and 30 keV are regarded conventionally as the mean energy of the energy spectrum when the accelerating voltages of the X-ray tube are 40 kV and 50 kV, respectively), R is the radius of the cylinder,  is the measured refractive angle,  is the real part and  is the imaginary part of the material's refractive index, and x is the variable.…”

“…[8][9][10][11][12][13] However, generally speaking, for an X-ray Talbot-Lau interferometer, because the phase shift and the Talbot distance of the phase grating are directly related to the wavelength of the X-ray, the accelerating voltage of the X-ray tube is chosen such that the mean energy of the energy spectrum emitted from the X-ray source matches the designed energy of the phase grating. 8,14 For example, when the designed energy of an X-ray Talbot-Lau interferometer is 27 keV, the tube voltage of the X-ray source should be set in the range of approximately 35-45 kV, meaning the system does not work efficiently when the X-ray tube is operated at a tube voltage of 60 kV. 14 Therefore, conducting dual-energy imaging with an X-ray Talbot-Lau interferometer is not straightforward.…”

“…8,14 For example, when the designed energy of an X-ray Talbot-Lau interferometer is 27 keV, the tube voltage of the X-ray source should be set in the range of approximately 35-45 kV, meaning the system does not work efficiently when the X-ray tube is operated at a tube voltage of 60 kV. 14 Therefore, conducting dual-energy imaging with an X-ray Talbot-Lau interferometer is not straightforward. 6 Note that the high energy and the low energy chosen in the dual-energy imaging should be sufficiently different in order to obtain considerably different signals, for example, 40 kV and 70 kV.…”

Simple phase extraction in x-ray differential phase contrast imaging

“…Besides conventional absorption images, phase-sensitive imaging can offer two other images: phase distribution and dark field distribution. [1][2][3][4] Various phase-sensitive techniques have been proposed and developed over the past decade. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Among them, the differential phase contrast (DPC) imaging can be used in a broad range of applications due to its low requirements for source coherence, mechanical stability and detector resolution.…”