Low dose and high SNR phase retrieval and micro CT using a wide area photon counting detector

Ian E. Harmon; Ivan Vazquez; Mini Das

doi:10.1117/12.2550548

16 March 2020 Low dose and high SNR phase retrieval and micro CT using a wide area photon counting detector

Ian E. Harmon, Ivan Vazquez, Mini Das

Proceedings Volume 11312, Medical Imaging 2020: Physics of Medical Imaging; 113121C (2020) https://doi.org/10.1117/12.2550548
Event: SPIE Medical Imaging, 2020, Houston, Texas, United States

Abstract

X-ray phase contrast imaging has been proposed as a way to improve contrast in soft tissue. Phase retrieval methods have been developed which only require a single image acquisition, allowing phase contrast imaging to be used in combination with computed tomography without a dangerously large dose applied to the subject. Many of the existing methods use approximations regarding the knowledge of object properties as well as make assumptions such as a constant ratio of absorption and phase properties throughout the object.¹ Our group has previously developed a phase retrieval algorithm which only requires a single image when using energy-resolving photon counting detectors and uses no additional approximations regarding object properties. This allows us to decompose phase properties even if the object is composed of a large number of materials with very close material properties. Our recent results on simple phantoms show that we can accurately retrieve multiple material properties corresponding to absorption and phase effects for a range of different materials. The strength of our spectral decomposition method is compounded by the use of photon counting detectors with zero dark noise. In this paper we demonstrate the first propagation-based phase contrast tomography study of a biological sample using our method. Our phase retrieval method yields excellent results with very low counts - 1 second or less per projection acquisitions using a weak microfocal X-Ray tube. We show this via known phantoms as well as satisfactory preliminary results from biological samples. Additional studies will explore dose aspects using mouse models in our benchtop micro computed tomography platform and compare against attenuation-based computed tomography.

Conference Presentation

Citation Download Citation

Ian E. Harmon, Ivan Vazquez, and Mini Das "Low dose and high SNR phase retrieval and micro CT using a wide area photon counting detector", Proc. SPIE 11312, Medical Imaging 2020: Physics of Medical Imaging, 113121C (16 March 2020); https://doi.org/10.1117/12.2550548

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