Browse Prior Art Database

SYSTEM AND METHOD FOR VIRTUAL MONOCHROMATIC IMAGE GENERATION FROM SINGLE-ENERGY CT WITH MULTI-MATERIAL CORRECTION

IP.com Disclosure Number: IPCOM000236868D
Publication Date: 2014-May-20

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention proposes a straightforward technique to generate multi-material correction (MMC) images at arbitrary energy from MMC images under one or two other energy levels. In addition, taking advantage of MMC, the technique provides an approach to achieve good CT number mapping and beam-hardening artifacts reduction for PET-CT attenuation correction. The invention further proposed that MMC is applied to radiotherapy planning CT as well to improve accuracy of electronic density calculation without a stoichiometric calibration.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 24% of the total text.

 

SYSTEM AND METHOD FOR VIRTUAL MONOCHROMATIC IMAGE GENERATION FROM SINGLE-ENERGY CT WITH MULTI-MATERIAL CORRECTION

BRIEF ABSTRACT

The invention proposes a straightforward technique to generate multi-material correction (MMC) images at arbitrary energy from MMC images under one or two other energy levels. In addition, taking advantage of MMC, the technique provides an approach to achieve good CT number mapping and beam-hardening artifacts reduction for PET-CT attenuation correction. The invention further proposed that MMC is applied to radiotherapy planning CT as well to improve accuracy of electronic density calculation without a stoichiometric calibration.

KEYWORDS

            MMC, PET-CT, attenuation correction, radiotherapy planning CT, monochromatic image

DETAILED DESCRIPTION

A Multi-lateral correction (MMC) algorithm is known in the prior art for spectral calibration such named as beam hardening correction (BHC) for wide-cone computed tomography (CT). The algorithm is effective to correct spectral issues caused by source, object and detector and are applied to multiple materials. In general, MMC eliminates beam hardening artifacts in CT image and achieves monochromatic image (mono image) at an effective energy (keV) determined in advance. Because of this monochromatic property, there is an increase in demand for producing a serial of monochromatic images at different energy levels from MMC image similar to what in the dual energy. The MMC algorithm is designed to deal with multi materials such has bone, iodine, metal, and other high dense material. The algorithm consolidates multi corrections, low frequency and high frequency beam hardening (BH) artifacts corrections as well as correction for the heel effect induced CT number non-uniformity along the Z direction.

Therefore, there is a need in the art for virtual monochromatic image generation from single-energy CT with multi-material correction.

The proposed invention describes a technique to synthesize virtual monochromatic images at arbitrary energy level using existing MMC images at one or two energy levels. The technique describes how to apply MMC and synthesizing method to positron emission tomography - computed tomography (PET-CT) attenuation correction and for radiotherapy planning CT.

            The virtual monochromatic images from single-energy CT is generated as follows. In the first technique, when MMC images at two different energy levels are available, the virtual monochromatic CT images at any energy level are synthesized using weights which are associated only with the linear attenuation coefficients of iodine without extra image reconstruction. The second technique, when MMC image is available only at one energy level, there is no exact solution. However, approximate scaling of CT number is done to a desired energy level as long as segmentation maps and the base material fractions is stored for each identified material used in inverse base material ...