Method and system for defining a volume of interest in a physiological image

A multi-modality imaging system comprising:

• a first imaging modality apparatus operable to reconstruct an anatomical image of a target, the anatomical image having a first resolution;
• a second imaging modality apparatus operable to reconstruct a physiological image of the target, the physiological image having a second resolution lower than the first resolution;
• an image enhancement module comprising at least one processor programmed to:
• acquire the anatomical image from the first imaging modality apparatus;
• acquire the physiological image from the second imaging modality apparatus, the physiological image including a plurality of voxels;
• identify a target boundary of the target in the anatomical image;
• register the target boundary of the target to the physiological image;
• identify voxels of the physiological image that are completely within the target boundary;
• calculate an inner activity value by summing activity levels of the voxels of the physiological image completely within the target boundary;
• identify partial volume voxels of the physiological image that include the target boundary;
• assign a weight to each of the partial volume voxels;
• multiply the weight of each partial volume voxel by an average target activity level to determine a modified activity level for each partial volume voxel;
• calculate a partial volume activity value by summing the modified activity levels of the partial volume voxels;
• combine the inner activity value and the partial volume activity;
• and
• modify the physiological image using the combined inner activity value and partial volume activity to provide a corrected physiological image.

A non-transitory computer-readable medium encoded with a program to instruct a computer to:

• acquire an anatomical image having a first resolution using a first imaging modality;
• acquire a physiological image having a second resolution lower than the first resolution using a second imaging modality, the physiological image including a plurality of voxels;
• identify a target boundary of the target in the anatomical image;
• apply the target boundary of the target to the physiological image;
• identify voxels of the physiological image that are completely within the target boundary;
• calculate an inner activity value by summing activity levels of the voxels of the physiological image completely within the target boundary;
• identify partial volume voxels of the physiological image that include the target boundary;
• assign a weight to each of the partial volume voxels;
• multiply the weight of each partial volume voxel by an average target activity level to determine a modified activity level for each partial volume voxel;
• calculate a partial volume activity value by summing the modified activity levels of the partial volume voxels;
• combine the inner activity value and the partial volume activity;
• and
• modify the physiological image using the combined inner activity value and partial volume activity to provide a corrected physiological image.