2020/02/29 by Mats Persson, Adam Wang, Persson, Mats +3 · 1 citation
Engineering · Medicine · #Advanced X-ray and CT Imaging #FOS: Physical sciences #Medical Imaging Techniques and Applications #Medical Physics (physics.med-ph) #Radiation Dose and Imaging
paper · pdf · doi:10.48550/arxiv.2003.00390
openalex publication_date 2020/02/29 · openalex created_date 2022/07/26 · openalex updated_date 2026/07/28
Purpose: Developing photon-counting CT detectors requires understanding the\nimpact of parameters such as converter material, absorption length and pixel\nsize. We apply a novel linear-systems framework, incorporating spatial and\nenergy resolution, to study realistic silicon (Si) and cadmium telluride (CdTe)\ndetectors at low count rate. Approach: We compared CdTe detector designs with\n0.5\×0.5 ; \mm2 and 0.225\×0.225 ; \mm2 pixels\nand Si detector designs with 0.5\×0.5 ; \mm2 pixels of 30 and 60\nmm active absorption length, with and without tungsten scatter blockers.\nMonte-Carlo simulations of photon transport were used together with Gaussian\ncharge sharing models fitted to published data. Results: For detection in a 300\nmm thick object at 120 kVp, the 0.5 mm and 0.225 mm pixel CdTe systems have\n28-41 % and 5-29 % higher DQE, respectively, than the 60 mm Si system\nwith tungsten, whereas the corresponding numbers for two-material decomposition\nare 2 % lower to 11 % higher DQE and 31-54 % lower DQE compared to Si.\nWe also show that combining these detectors with dual-spectrum acquisition is\nbeneficial. Conclusions: In the low-count-rate regime, CdTe detector systems\noutperform the Si systems for detection tasks, while silicon outperforms one or\nboth of the CdTe systems for material decomposition.\n