Johns Hopkins University

Siemens Aktiengesellschaft

Adam S Wang

Jeffrey H Siewerdsen

Gerhard Kleinszig

Ali Uneri

Sebastian Vogt

Joseph Webster Stayman

Yoshito Otake

Sarah Ouadah

The present invention is directed to a method for enabling volumetric image reconstruction from unknown projection geometry of tomographic imaging systems, including CT, cone-beam CT (CBCT), and tomosynthesis systems. The invention enables image reconstruction in cases where it was not previously possible (e.g., custom-designed trajectories on robotic C-arms, or systems using uncalibrated geometries), and more broadly offers improved image quality (e.g., improved spatial resolution and reduced streak artifact) and robustness to patient motion (e.g., inherent compensation for rigid motion) in a manner that does not alter the patient setup or imaging workflow. The method provides a means for accurately estimating the complete geometric description of each projection acquired during a scan by simulating various poses of the x-ray source and detector to determine their unique, scan-specific positions relative to the patient, which is often unknown or inexactly known (e.g., a custom-designed trajectory, or scan-to-scan variability in source and detector position).

Self-calibrating projection geometry for volumetric image reconstruction

A novel method for simulating radiation dose reduction that enables previews of low-dose x-ray projection images, low-dose computed tomography images and/or cone-beam CT images. Given an existing projection or set of projections of the patient acquired at a nominal dose, the method provides a means to produce highly accurate preview images that accurately reflect the image quality associated with reduced radiation dose. The low-dose preview image accounts for characteristics of the imaging system, including blur, variations in detector gain and electronic noise, and does so in a manner that yields accurate depiction of the magnitude and correlation of image noise in the preview images. A calibration step may be included to establish the system-specific relationship between the mean and variance in detector signal, and incorporate an accurate model for system blur such that correlations in the resulting LDP images are accurate.

System, method and computer readable medium for preview of low-dose x-ray projection and tomographic images

A method of generating a preview of at least one low-dose x-ray image includes the followings steps: obtaining an initial volumetric representation of a patient from an x-ray device; creating at least one x-ray image projection from the initial volumetric representation; injecting correlated noise into at least one of the x-ray image projections; and processing the noise-injected x-ray image projections to create at least one preview of a patient-specific low-dose x-ray for showing to a user. There are also described a device for generating at least one preview of a low-dose x-ray image, a corresponding imaging system, and a non-transitory computer readable medium.

Method and device for generating a low-dose X-ray image preview, imaging system and computer program product

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Baltimore, MD, United States of America

Adam S Wang