Laboratory x-ray nano-computed tomography for biomedical research

TL;DR

This paper presents a laboratory x-ray nano-CT system with high resolution and contrast enhancement, enabling biomedical imaging without synchrotron sources, and demonstrates its effectiveness with biological samples.

Contribution

The paper introduces a novel laboratory setup for x-ray nano-CT using a nano-focus source and photon counting detectors, achieving sub-micron resolution without optical elements.

Findings

Photon counting detectors outperform scintillator-based detectors in low-flux, low-contrast scenarios.

Propagation-based phase contrast enhances sample contrast.

System achieves sub-micron resolution suitable for biological tissues.

Abstract

High-resolution x-ray tomography is a common technique for biomedical research using synchrotron sources. With advancements in laboratory x-ray sources, an increasing number of experiments can be performed in the lab. In this paper, the design, implementation, and verification of a laboratory setup for x-ray nano-computed tomography is presented using a nano-focus x-ray source and high geometric magnification not requiring any optical elements. Comparing a scintillator-based detector to a photon counting detector shows a clear benefit of using photon counting detectors for these applications, where the flux of the x-ray source is limited and samples have low contrast. Sample contrast is enhanced using propagation-based phase contrast. The resolution of the system is verified using 2D resolution charts and using Fourier Ring Correlation on reconstructed CT slices. Evaluating noise and contrast highlights the benefits of photon counting detectors and the contrast improvement through phase contrast. The implemented setup is capable of reaching sub-micron resolution and satisfying contrast in biological samples, like paraffin embedded tissue.