A pre-clinical Talbot-Lau prototype for X-ray dark-field imaging of human-sized objects

Talbot-Lau X-ray interferometry provides information about the scattering and refractive properties of an object { in addition to the object's attenuation features. Until recently, this method was ineligible for imaging human-sized objects as it is challenging to adapt Talbot-Lau interferometers (TLIs) to the relevant X-ray energy ranges. In this work, we present a pre-clinical Talbot-Lau prototype capable of imaging human-sized objects with proper image quality at clinically acceptable dose levels. The TLI is designed to match a setup of clinical relevance as closely as possible. The system provides a scan range of 120X30 cm by using a scanning beam geometry. Its ultimate load is 100 kg. High aspect ratios and fine grid periods of the gratings ensure a reasonable setup length and clinically relevant image quality. The system is installed in a university hospital and is therefore exposed to the external influences of a clinical environment. To demonstrate the system's capabilities, a full-body scan of a euthanized pig was performed. In addition, freshly excised porcine lungs with an extrinsically provoked pneumothorax were mounted into a human thorax phantom and examined with the prototype. Both examination sequences resulted in clinically relevant image quality - even in the case of a skin entrance air kerma of only 0.3mGy which is in the range of human thoracic imaging. The presented case of a pneumothorax and a reader study showed that the prototype's dark-field images provide added value for pulmonary diagnosis. We demonstrated that a dedicated design of a Talbot-Lau interferometer can be applied to medical imaging by constructing a pre-clinical Talbot-Lau prototype. We experienced that the system is feasible for imaging human-sized objects and the phase-stepping approach is suitable for clinical practice. Hence, we conclude that Talbot-Lau X-ray imaging has potential for clinical use and enhances the diagnostic power of medical X-ray imaging. This article is protected by copyright. All rights reserved.