Systems and methods for positron emission tomography image reconstruction

An imaging method implemented on at least one machine each of which has at least one processor and storage, the method comprising:

• obtaining an anatomical image of a scanning area of a subject, the anatomical image being unaffected by respiratory motion;
• obtaining positron emission tomography (PET) data of the scanning area of the subject, the PET data being affected by a respiratory motion of the subject;
• binning the PET data into a plurality of respiratory phases of the respiratory motion of the subject, the plurality of respiratory phases including a first respiratory phase and a second respiratory phase;
• reconstructing, based on the binned PET data, a plurality of gated PET images;
• determining a target motion vector field between the anatomical image and a target gated PET image among the plurality of gated PET images, wherein the determining a target motion vector field between the anatomical image and a target gated PET image among the plurality of gated PET images comprises:
• determining a first motion vector field between a first gated PET image corresponding to the first respiratory phase and a second gated PET image corresponding to the second respiratory phase;
• determining a second motion vector field between the anatomical image and the second gated PET image based on the first motion vector field;
• and
• determining the target motion vector field between the anatomical image and the target gated PET image based on the first motion vector field and the second motion vector field;
• and
• generating, based on the anatomical image and the target motion vector field, an attenuation corrected target gated PET image by performing a phase-matched attenuation correction on the target gated PET data, wherein the attenuation corrected PET image corresponds to a certain respiratory phase including a reference respiratory phase or an average of the plurality of respiratory phases.

A system, comprising:

• at least one non-transitory storage medium including a set of instructions for reconstructing a positron emission tomography (PET) image;
• and
• at least one processor configured to communicate with the at least one non-transitory storage medium, wherein when executing the set of instructions, the system is directed to:
• obtain an anatomical image of a scanning area of a subject acquired when the subject remains in a breath-hold status;
• obtain PET data of the scanning area of the subject, the PET data corresponding to a respiration signal with a plurality of respiratory phases of the subject, the respiratory phases including a first respiratory phase and a second respiratory phase;
• gate the PET data into a plurality of bins based on the plurality of respiratory phases of the respiration signal;
• reconstruct, based on the gated PET data, a plurality of gated PET images corresponding to the plurality of respiratory phases, the plurality of gated PET images including a first gated PET image corresponding to the first respiratory phase and a second gated PET image corresponding to the second respiratory phase;
• determine a first motion vector field between the first gated PET image and the second gated PET image;
• determine, based on the first motion vector field, a second motion vector field between the anatomical image and the second gated PET image;
• and
• reconstruct an attenuation corrected PET image based on the PET data, the second motion vector field, and the anatomical image, wherein the attenuation corrected PET image corresponds to a certain respiratory phase including a reference respiratory phase or an average of the plurality of respiratory phases.