Semester of Graduation

Spring 2026

Degree

Master of Science (MS)

Department

Medical Physics

Document Type

Thesis

Abstract

X-ray interferometry provides valuable information on attenuation, small-angle scattering, and differential phase contrast. This multi-modal contrast can aid in many clinical applications, such as lung diseases and breast cancer. However, standard inter- ferometry has an analyzer grating that can increase the dose requirement to maintain the same image quality as a standard X-ray. We propose the use of super-resolution methods for X-ray grating interferometry without an analyzer, with detectors that fail to meet the Nyquist sampling rate needed for traditional image recovery algorithms. Detector phase- steps are used to nominally recover the sampling and iteratively recover the visibility and the object parameters. This method enables Talbot-Lau interferometry without the X-ray absorbing analyzer. It also allows for smaller fringe periods (Pd) or higher autocorrela- tion lengths for the analyzer-less Modulated Phase Grating Interferometer. This will allow for reduced X-ray dose and higher autocorrelation lengths than previously accessible. It demonstrates the use of super-resolution methods to iteratively reconstruct attenuation, differential-phase, and dark-field images using simulations of two-dimensional lung phan- toms with lesions. Direct detector with 75 μm and 30 μm pixel size, modeled using a pill- box (box-blur) point spread function (PSF). Scintillator-based detectors were tested with 50 μm and 75 μm pixel sizes, modeled using Gaussian PSFs. The thesis shows that super- resolution iterative reconstruction methods are robust to noise and can be used to improve grating interferometry for cases where traditional algorithms cannot be used.

Date

4-20-2026

Committee Chair

Joyoni Dey

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

Download

Share

COinS