Canon Medical Systems Corporation

Xiaochun Lai

Yi Qiang

Xiaohui Zhan

Liang Cai

Wenyuan Qi

Peng Peng

Kevin Christopher Zimmerman

Zhihong Ye

A method and apparatus for diagnosing and/or calibrating underperforming pixels in detectors in a small pixelated photon counting CT system utilizes a series of tests on image data acquired in-situ as part of a series of calibration scans in the CT system. Tests are performed on the acquired data to determine the existence of underperforming pixels within the detectors such that the information acquired by those pixels can be replaced by alternate data from surrounding pixels (e.g. by interpolation). The underperforming pixels are stored in 'bad' pixel tables and may be specific to a type of image (e.g., spectral or counting) and a specific protocol.

Bad detector calibration methods and workflow for a small pixelated photon counting CT system

Multiple interactions, such as Compton scattering, inside a PET detector are used to predict an incident photon's direction for identifying true coincidence events versus scatter/random coincidence events by creating a cone shaped shell projection defining a range of possible flight directions for the incident photon. The disclosed techniques can be used as prior information to improve the image reconstruction process. The disclosed techniques can be implemented in a LYSO/SiPM-based layer stacked detector, which can precisely register multiple interactions' 3D position.

Scatter and random coincidence rejection

An embodiment of a computed tomography apparatus includes an x-ray source and scan control circuitry configured to control the x-ray source to expose a subject with x-rays over a scan having a plurality of views. A detector is disposed to receive x-rays from the x-ray source, has a plurality of anodes arranged in groups, and a common conductive strip between the anodes. Photon counting circuits are respectively provided for each of the anodes and have adjustable operating parameters. Connection circuitry is configured to adaptively connect, in a first mode, each anode to one of the photon counting circuits and, in a second mode, each anode in a group to a same one of the photon counting circuits. Processing circuitry, connected to the connection circuitry and the photon counting circuits, is configured to, for each of the views, select the first mode or the second mode and adjust the operating parameters based upon exposure data obtained from exposing the subject with the x-rays from the x-ray source.

X-ray CT apparatus with adaptive photon counting detectors

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Vernon Hills, IL, United States of America

Xiaochun Lai