Material-specific attenuation maps for combined imaging systems

A method of generating an attenuation map, comprising:

• receiving computed tomography (CT) scan data for a CT scan including an imaging component, wherein the CT scan data comprises a plurality of voxels each having a scanned CT value;
• identifying material in each voxel of the plurality of voxels by comparing the scanned CT value for the voxel with predetermined CT values for a plurality of materials related to a radiodensity of one of organic material or non-organic material and energy levels of the CT scan;
• determining an image modality-specific voxel attenuation value for each voxel based on the predetermined CT value and an attenuation value for the identified one of the organic material or the non-organic material;
• and
• generating an attenuation map including the determined imaging modality-specific voxel attenuation value for each voxel, wherein the attenuation map is configured for attenuation correction of an imaging modality including the imaging component with a field of view of the imaging modality, modality-specific attenuation values, and energy-specific attenuation values.