Method, apparatus, and computer-readable medium for pre-reconstruction decomposition and calibration in dual energy computed tomography

An apparatus for obtaining a computed tomography image of an object, the apparatus comprising:

• a dual-energy projection data obtaining section configured to obtain object dual-energy projection data of the object;
• a calculating section configured to obtain average attenuation coefficients and non-linear beam hardening coefficients;
• a line integral determining portion configured to determine, for the object dual-energy projection data, a pair of line integral equations that, upon introducing the average attenuation coefficients, are reorganized into a pair of reorganized line integral equations including linear terms and non-linear beam hardening terms;
• an initial value obtaining section configured to obtain an initial solution of the reorganized line integral equations by setting the non-linear beam hardening terms to zero;
• an iteratively solving section configured to iteratively solve the reorganized line integral equations starting with the initial solutions to obtain a first basis line integral solution for a first basis material and a second basis line integral solution for a second basis material;
• and
• a reconstructing section configured to reconstruct the computed tomography image of the object based on the first basis line integral solution for the first basis material and the second basis line integral solution for the second basis material.

A computer-readable medium having computer program instructions that, when executed on a computer, cause the computer to perform steps to obtain a computed tomography image of an object, the steps comprising:

• obtaining object dual-energy projection data of the object;
• obtaining average attenuation coefficients and non-linear beam hardening coefficients;
• determining, for the object dual-energy projection data, a pair of line integral equations that, upon introducing the average attenuation coefficients, are reorganized into a pair of reorganized line integral equations including linear terms and non-linear beam hardening terms;
• obtaining initial solutions of the reorganized line integral equations by setting the non-linear beam hardening terms to zero;
• iteratively solving the reorganized line integral equations starting with the initial solutions to obtain a first basis line integral solution for a first basis material and a second basis line integral solution for a second basis material;
• and
• reconstructing the computed tomography image of the object based on the first basis line integral solution for the first basis material and the second basis line integral solution for the second basis material.

A method of obtaining a computed tomography image of an object, the method comprising:

• obtaining object dual-energy projection data of the object;
• obtaining phantom dual-energy projection data of a phantom including the first basis material and the second basis material,
• wherein most of an attenuation by the first basis material in the phantom dual-energy projection data corresponds to a photoelectric attenuation process, and most of an attenuation by the second basis material in the dual-energy projection data corresponds to a Compton attenuation process;
• and
• reconstructing the computed tomography image of the object based on a first basis line integral solution for the first basis material and a second basis line integral solution for the second basis material.

An apparatus for obtaining a computed tomography image of an object, the apparatus comprising:

• a dual-energy projection data obtaining section configured to obtain object dual-energy projection data of the object;
• a calibration section configured to obtain phantom dual-energy projection data of a phantom including the first basis material and the second basis material,
• wherein most of an attenuation by the first basis material in the phantom dual-energy projection data corresponds to a photoelectric attenuation process, and most of an attenuation by the second basis material in the dual-energy projection data corresponds to a Compton attenuation process;
• and
• a reconstructing section configured to reconstruct the computed tomography image of the object based on a first basis line integral solution for the first basis material and a second basis line integral solution for the second basis material.