Dual-contrast photon-counting micro-CT using iodine and a novel bismuth-based contrast agent

OBJECTIVES

To characterize for the first time in-vivo a novel bismuth-based nanoparticular contrast agent developed for preclinical applications. Then, to design and test in-vivo a multi-contrast protocol for functional cardiac imaging using the new bismuth nanoparticles and a well-established iodine-based contrast agent.
Approach. A micro-CT scanner was assembled and equipped with a photon-counting detector. Five mice were administered with the bismuth-based contrast agent and systematically scanned over 5 h to quantify the contrast enhancement in relevant organs of interest. Subsequently, the multi-contrast agent protocol was tested on three mice. Material decomposition was performed on the acquired spectral data to quantify the concentration of bismuth and iodine in multiple structures, e.g. the myocardium and vasculature.
Main results. In the vasculature, the bismuth agent provides a peak enhancement of 1100HU and a half-life of about 260 minutes. After the injection, it accumulates in the liver, spleen and intestinal wall reaching a CT value of 440HU about 5 h post injection. Phantom measurements showed that the bismuth provides more contrast enhancement than iodine for a variety of tube voltages. The multi-contrast protocol for cardiac imaging successfully allowed the simultaneous decomposition of the vasculature, the brown adipose tissue and the myocardium.
Significance. The new bismuth-based contrast agent was proven to have a long circulation time suitable for preclinical applications and to provide more contrast than iodine agents. The proposed multi--contrast protocol resulted in a new tool for cardiac functional imaging. Furthermore, thanks to the contrast enhancement provided in the intestinal wall, the novel contrast agent may be used to develop further multi-contrast agent protocols for abdominal and oncological imaging&#xD.

IYCr Open Factory: Inviting Young Crystallographers to Europe – Status & Outlook

The STOE DECTRIS Xenocs OpenFactory will take place from 10 to 19 September 2014. Participants receive seven days of intensive training by STOE, DECTRIS and Xenocs staff and guest scientists in cooperation with the IUCr. The training will focus on teaching participants the relevant theoretical skillset as well as giving practical training. In Grenoble, the delegates will spend significant time at the ESRF (European Synchrotron) and will be trained in Small Angle X-ray scattering at Xenocs' headquarters. In Darmstadt, the participants will be trained in Single Crystal and Powder XRD at STOE's headquarter. Delegates will have the opportunity to visit beamlines and interact with scientists at ESRF. Starting on 18 September, all OpenFactory participants will join the STOE annual user meeting. The user meeting is a platform for the exchange of ideas among its participants as well as speeches to highlight recent research results. It will be a unique opportunity for OpenFactory participants to interact with highly experienced XRD users and to build up relevant networks. This presentation and poster will highlight the activity, the focus of the program and present the selected participants for the OpenFactory event. The intention is to update on the status of the OpenFactory, but even more important, to encourage similar activities within and after the International Year of Crystallography. In this context, the presenter will discuss any insights from the applications received, i.e. geographies with particular high interest in the OpenFactory, which could be used to follow up on the OpenFactory with future events.

X-ray imaging with the PILATUS 100k detector

We report on the application of the PILATUS 100K pixel detector for medical imaging. Experimental results are presented in the form of X-ray radiographs using standard X-ray absorption contrast and a recently developed phase contrast imaging method. The results obtained with the PILATUS detector are compared to results obtained with a conventional X-ray imaging system consisting of an X-ray scintillation screen, lens optics, and a charge coupled device. Finally, the results for both systems are discussed more quantitatively based on an image power spectrum analysis.

Synchrotron beam test with a photon-counting pixel detector

Synchrotron beam measurements were performed with a single-photon-counting pixel detector to investigate the influence of threshold settings on charge sharing. Improvement of image homogeneity by adjusting the threshold of each pixel individually was demonstrated. With a flat-field correction, the homogeneity could be improved. A measurement of the point spread function is reported.