Improved intrinsic motion detection using time-of-flight PET.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Image Reconstruction

Background:

• Current motion detection in PET relies on center-of-mass (COM) changes, which are limited by target contrast and axial data truncation.
• Stationary backgrounds in PET data reduce COM displacement, and axially truncated data introduce bias, impacting motion gating signal accuracy.

Purpose of the Study:

• To enhance intrinsic motion detection for improved motion-compensated image reconstruction in PET.
• To develop a more robust motion gating signal by addressing limitations of traditional COM-based methods.

Main Methods:

• Utilized time-of-flight (TOF) PET data to compute volume-of-interest (VOI) weighted data, reducing stationary background influence.
• Derived rebinning equations to accurately calculate axial COM from truncated PET data.
• Analyzed COM variance with and without VOI weighting and axial truncation compensation.

Main Results:

• VOI weighting increased COM displacement, leading to a more sensitive motion gating signal.
• Accurate axial COM calculation was achieved using derived rebinning equations.
• Simulations, phantom, and patient data confirmed the method's effectiveness in motion phase identification.

Conclusions:

• The proposed VOI-weighted COM approach significantly improves intrinsic motion detection for PET.
• This method provides a more reliable gating signal for motion-compensated image reconstruction.
• The technique offers a valuable advancement in PET imaging quality and accuracy.