Image reconstruction for interrupted-beam x-ray CT on diagnostic clinical scanners

Matthew J. Muckley, Baiyu Chen, Thomas Vahle, Thomas O'Donnell, Florian Knoll, Aaron D. Sodickson, Daniel K. Sodickson, Ricardo Otazo

    Research output: Contribution to journalArticle

    Abstract

    Low-dose x-ray CT is a major research area with high clinical impact. Compressed sensing using view-based sparse sampling and sparsity-promoting regularization has shown promise in simulations, but these methods can be difficult to implement on diagnostic clinical CT scanners since the x-ray beam cannot be switched on and off rapidly enough. An alternative to view-based sparse sampling is interrupted-beam sparse sampling. SparseCT is a recently-proposed interrupted-beam scheme that achieves sparse sampling by blocking a portion of the beam using a multislit collimator (MSC). The use of an MSC necessitates a number of modifications to the standard compressed sensing reconstruction pipeline. In particular, we find that SparseCT reconstruction is feasible within a model-based image reconstruction framework that incorporates data fidelity weighting to consider penumbra effects and source jittering to consider the effect of partial source obstruction. Here, we present these modifications and demonstrate their application in simulations and real-world prototype scans. In simulations compared to conventional low-dose acquisitions, SparseCT is able to achieve smaller normalized root-mean square differences and higher structural similarity measures on two reduction factors. In prototype experiments, we successfully apply our reconstruction modifications and maintain image resolution at quarter-dose reduction level. The SparseCT design requires only small hardware modifications to current diagnostic clinical scanners, opening up new possibilities for CT dose reduction.

    Original languageEnglish (US)
    Article number155007
    JournalPhysics in Medicine and Biology
    Volume64
    Issue number15
    DOIs
    StatePublished - Aug 6 2019

    Keywords

    • compressed sensing
    • interrupted-beam CT
    • low-dose CT

    ASJC Scopus subject areas

    • Radiological and Ultrasound Technology
    • Radiology Nuclear Medicine and imaging

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  • Cite this

    Muckley, M. J., Chen, B., Vahle, T., O'Donnell, T., Knoll, F., Sodickson, A. D., Sodickson, D. K., & Otazo, R. (2019). Image reconstruction for interrupted-beam x-ray CT on diagnostic clinical scanners. Physics in Medicine and Biology, 64(15), [155007]. https://doi.org/10.1088/1361-6560/ab2df1