System and method for joint estimation of attenuation and activity information

An imaging system for imaging a subject, comprising:

• an emission tomography system configured to acquire emission scan data corresponding to the subject;
• an anatomical scan system operatively coupled to the emission tomography system and configured to acquire anatomical scan data corresponding to the subject;
• a processing subsystem operationally coupled to one or more of the anatomical scan system and the emission tomography system, wherein the processing subsystem is configured to:
• reconstruct one or more at least partial anatomical scan images using the anatomical scan data;
• generate an image-space certainty map that represents a level of confidence corresponding to an attenuation coefficient for one or more selected voxels by processing the one or more at least partial anatomical scan images;
• generate a preliminary attenuation map based on the one or more at least partial anatomical scan images;
• initialize one or more of a selected set of attenuation factors in a projection-space corresponding to the emission scan data based on the preliminary attenuation map;
• generate a projection-space certainty map corresponding to the emission scan data that represents a level of confidence corresponding to the value of one or more of the selected set of attenuation factors based on the image-space certainty map;
• initialize an emission image corresponding to the target volume in the subject;
• iteratively update one or more of the selected attenuation factors and the emission image based on the emission scan data, the projection-space certainty map, the initial attenuation factors, the initial emission image, or combinations thereof;
• and
• determine a desired emission image, desired values of the attenuation factors, or a combination thereof, based on the iteratively updated attenuation factors and the iteratively updated emission image.

A non-transitory computer readable medium that stores instructions executable by one or more processors to perform a method for imaging, comprising:

• receiving emission scan data and anatomical scan data;
• reconstructing one or more at least partial anatomical scan images using the anatomical scan data;
• generating an image-space certainty map that represents a level of confidence corresponding to an attenuation coefficient for one or more selected voxels in the one or more at least partial anatomical scan images;
• generating a preliminary attenuation map based on the one or more at least partial anatomical scan images;
• initializing one or more of a selected set of attenuation factors in a projection-space corresponding to the emission scan data based on the preliminary attenuation map;
• generating a projection-space certainty map corresponding to the emission scan data that represents a level of confidence corresponding to the value of one or more of the selected set of attenuation factors based on the image-space certainty map;
• initializing an emission image corresponding to the target volume in the subject;
• iteratively updating one or more of the selected set of attenuation factors and the emission image based on the emission scan data, the projection-space certainty map, the initial attenuation factors, the initial emission image, or combinations thereof;
• and
• determining a desired emission image, desired values of the attenuation factors, or a combination thereof, based on the iteratively updated attenuation factors and the iteratively updated emission image.