Wuppertal 2015 – wissenschaftliches Programm

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ST: Fachverband Strahlen- und Medizinphysik

ST 1: Biomedical Imaging I

ST 1.5: Vortrag

Montag, 9. März 2015, 15:00–15:15, BZ.08.02 (HS 3)

Advanced X-ray image quality enhancement with the single-photon-counting LAMBDA detector — •Stephan Kaczmarz — Lehrstuhl für Biomedizinische Physik E17, James-Franck-Strasse 1 85748, Garching

In this work, the LAMBDA imaging system with the hybrid CMOS based Medipix3RX readout architecture is used and image quality improvements investigated. Besides numerous advantages like spectral information as well as the absence of dark current and readout noise, inevitable production tolerances of the small detector electronics can cause a decreased image uniformity. Additionally, the influence of the sample itself further degrades the image quality by beam hardening.

Therefore, this work probes the performance of the advanced Signal-to-equivalent-thickness calibration (STC) in comparison with the commonly used Flatfield-correction for bio-medical and material testing applications. The basic idea of STC is to translate the photon count-rate of a Raw image to a reference absorber thickness pixel-wise by a previously gained calibration map.

The results demonstrate the great performance of STC. Beam hardening can be drastically reduced as well as cupping artifacts in a CT scan. Sample features emerge that were not recognizable before as the image uniformity in increased. Furthermore, CdTe-sensor growing domain artifacts are completely removed and STC gives rise to image informations that were overlaid by those artifacts before. To sum up, STC greatly improves the absorption based X-ray image quality without increasing the applied radiation dose.