Information-based analysis of X-ray in-line phase tomography with application to the detection of iron oxide nanoparticles in the brain

Hugo Rositi,Cécile Olivier,Carole Frindel,Max Langer,David Rousseau,Marlène Wiart,Françoise Peyrin

doi:10.1364/oe.21.027185

Abstract

The study analyzes noise in X-ray in-line phase tomography in a biomedical context. The impact of noise on detection of iron oxide nanoparticles in mouse brain is assessed. The part of the noise due to the imaging system and the part due to biology are quantitatively expressed in a Neyman Pearson detection strategy with two models of noise. This represents a practical extension of previous work on noise in phase-contrast X-ray imaging which focused on the theoretical expression of the signal-to-noise ratio in mono-dimensional phantoms, taking account of the statistical noise of the imaging system only. We also report the impact of the phase retrieval step on detection performance. Taken together, this constitutes a general methodology of practical interest for quantitative extraction of information from X-ray in-line phase tomography, and is also relevant to assessment of contrast agents with a blob-like signature in high resolution imaging.

Highlights

X-ray phase contrast imaging is a field of coherent imaging which is receiving growing interest due to its greater sensitivity over conventional attenuation-based techniques
With such a mono-dimensional phantom, the detection scheme is only sensitive to the first order statistics of the noise. This does not take into account the possible correlation of the noise included in the second order statistics. We address this issue in a practical context with the detection problem of bidimensional heterogeneous objects with one phase contrast imaging technique, namely in-line phase tomography (IPT) in a biomedical application framework: the detection of iron oxide nanoparticles in excised mouse brain
IPT acquisitions in the propagation based imaging mode are performed on the synchrotron radiation beamline ID19 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France

Summary

Introduction

X-ray phase contrast imaging is a field of coherent imaging which is receiving growing interest due to its greater sensitivity over conventional attenuation-based techniques (see [1] for an introduction to this field). In X-ray phase-contrast imaging, refraction of a partially coherent X-ray beam by the object of interest slightly modifies the original wavefront profile. These variations result in changes in the locally transmitted intensity of the wave which contains quantitative information on the phase shift induced by the object. Over the last two decades, a number of acquisition techniques coupled with phase retrieval algorithms have been developed. The performances of such acquisitions and reconstruction techniques are usually assessed for methodological purposes in terms of linear fidelity of 3D reconstruction with respect to calibrated phantoms [4]

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Conclusion