Dark-field computed tomography reaches the human scale

Abstract

X-ray computed tomography (CT) is one of the most commonly used three-dimensional medical imaging modalities today. It has been refined over several decades, with the most recent innovations including dual-energy and spectral photon-counting technologies. Nevertheless, it has been discovered that wave-optical contrast mechanisms—beyond the presently used X-ray attenuation—offer the potential of complementary information, particularly on otherwise unresolved tissue microstructure. One such approach is dark-field imaging, which has recently been introduced and already demonstrated significantly improved radiological benefit in small-animal models, especially for lung diseases. Until now, however, dark-field CT could not yet be translated to the human scale and has been restricted to benchtop and small-animal systems, with scan durations of several minutes or more. This is mainly because the adaption and upscaling to the mechanical complexity, speed, and size of a human CT scanner so far remained an unsolved challenge. Here, we now report the successful integration of a Talbot–Lau interferometer into a clinical CT gantry and present dark-field CT results of a human-sized anthropomorphic body phantom, reconstructed from a single rotation scan performed in 1 s. Moreover, we present our key hardware and software solutions to the previously unsolved roadblocks, which so far have kept dark-field CT from being translated from the optical bench into a rapidly rotating CT gantry, with all its associated challenges like vibrations, continuous rotation, and large field of view. This development enables clinical dark-field CT studies with human patients in the near future.

Image guidance for FLASH radiotherapy

“…89,90 This could for example apply to pulmonary structures or brain injuries, which could be imaged with greater details than conventional imaging approaches, as shown by recent clinical 91 and preclinical 92,93 diagnostic investigations with prototype setups. Although availability of these technologies remains limited and clinical applicability in tomographic setups is still questionable both in terms of technical feasibility and imaging dose, they could play an important role in in vivo preclinical research to provide new insights, which could bring us a step further in our understanding of tumor and normal tissue responses to FLASH-RT, 94 to pave the way for a more efficient clinical translation.…”

Technical Design Considerations of a Human-Scale Talbot-Lau Interferometer for Dark-Field CT

“…As has recently been demonstrated in [21], the Philips Brilliance iCT SP is a suitable candidate as a base system for a dark-field CT. Its geometry is similar to most clinical CTs on the market (source-iso-center distance around 55 cm and detector-iso-center distance around 45 cm), it has only one high-power X-ray tube (120 kW), and 64 detector lines. After removal of its ultra-high-resolution comb the area in front of the anti-scatter grid and the detector is accessible for implementation of gratings and the modular collimator box can easily be modified.…”

“…To realize dark-field CT imaging for clinical application, however, non-trivial adaptations to the challenging environment of a rotating CT gantry and the only 1 m long beam path are required. In our recently published paper [21] we demonstrated the feasibility of such systems and presented first reconstruction results of dark-field images at human scale from our prototype implementation. In this paper, we now focus on the technical details and our design considerations which led to this prototype system.…”

Bioimaging guided pharmaceutical evaluations of nanomedicines for clinical translations

“…CT is a commonly applied modality in clinical imaging and is traditionally used for hard tissue visualization of bone due to the high disparity between the soft and hard tissues. CT can easily differentiate tissues with high electron density tissues from relatively electron-poor structures [ 137 ]. Consequently, it is commonly used for orthopedic purposes, as well as for hybrid imaging applications, providing anatomical data with high resolution to aid in the evaluation of PET/SPECT- and FLI-based protocols [ 138 , 139 ].…”