System and method for controlling zero-count errors in computed tomography

A medical imaging system comprising:

• an x-ray source configured to deliver x-rays to an object as the x-ray source is rotated about the object;
• a detector having a plurality of detector elements configured to receive the x-rays and generate computed tomography (CT) data therefrom;
• a controller configured to control the x-ray source to deliver the x-rays and to receive the CT data from the detector;
• a processor configured to:
• receive CT data of a subject from the detector;
• identify zero counts in the CT data;
• replace the zero counts in the CT data with at least one non-zero number to create zero-count free CT data;
• estimate a probability function of the zero-count free CT data;
• remove bias in the zero-count free CT data using the probability function;
• and
• reconstruct the zero-count free CT data after removal of the bias to create a corrected image of the subject with preserved conditional independence and spatial resolution.

A method for creating computed tomography (CT) images comprising:

• acquiring or accessing CT data of a subject;
• identifying zero counts in the CT data;
• replacing the zero counts in the CT data with at least one non-zero number to create zero-count free CT data;
• reducing a pre-log bias in the zero-count free CT data introduced by replacing of the zero counts with the at least one non-zero number;
• generating a sinogram estimator;
• reducing a post-log bias in the zero-count free CT data using the sinogram estimator;
• and
• reconstructing the zero-count free CT data after reducing the pre-log bias and the post-log bias to create an image of the subject.