Speaker
Description
Single absorption grating based X-ray phase contrast imaging (XPCI) with a hybrid pixel detector Timepix is a promising technique in many application fields (material sciences, biology, medicine etc.) [1]. Conventional grating interferometry uses two absorption gratings where one of them is moved in steps (so-called phase stepping). In contrast to that, the absorption, phase contrast and dark field images can be obtained in one acquisition using the proposed approach. On top of that, the single exposure method decreases the delivered dose and it is easier to maintain system stability without phase stepping.
Standard laboratory X-ray imaging setup equipped with Timepix detector and nano-focus X-ray tube was utilized for the measurements. The maximal source to detector distance (SDD) of the setup is roughly 90 cm, which provides long enough phase propagation path for 55 um large detector pixels. The system enables insertion and positioning of both 1D and 2D absorption gratings producing micro-line or micro-pencil beams, respectively.
In this system series of acquired phase contrast images taken under different angles can be used as input projections for computed tomography (CT). CT reconstructions were performed by both in-house and commercial software packages. Results of pilot CT measurements for phantoms and complex objects will be presented in the contribution.
[1] F. Krejčí, J. Jakůbek, M. Kroupa, "Single grating method for low dose 1-D and 2-D phase contrast X-ray imaging", Journal of Instrumentation 6 C01073 (2011)
