Multi-angle acquisition and 3D composite reconstruction for organ-targeted PET using planar detectors

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiological Physics

Background:

• Organ-targeted PET systems offer advantages over conventional PET/CT, including adjustable axial field-of-view (AFOV) and improved signal collection.
• Planar detector PET technology, while enabling quasi-3D reconstruction, faces limitations in axial spatial resolution and recovery coefficients (RCs).

Purpose of the Study:

• To evaluate a multi-angle image acquisition strategy combined with composite 3D reconstruction for organ-targeted PET.
• To improve axial spatial resolution and overcome intrinsic limitations of planar PET detectors.

Main Methods:

• The Radialis organ-targeted PET camera was used for experimental and simulated imaging.
• Acquisition and analysis involved custom phantoms, NEMA NU4-2008 IQ phantom, and a digital brain phantom.
• Image quality metrics, including line profiles, uniformity, RCs, and axial smearing, were compared between multi-angle and single-angle acquisitions.

Main Results:

• Multi-angle acquisition significantly reduced image smearing and improved uniformity (from ~10% to ~2.7%).
• Recovery coefficients (RCs) were enhanced, and hot spheres appeared more symmetrical in composite images.
• Simulations confirmed minimal axial smearing with a four-angle scan compared to a two-angle scan.

Conclusions:

• The multi-angle acquisition method effectively transforms planar PET detectors into a true tomographic system, enhancing image quality.
• This approach preserves the versatility of planar detector technology for organ-targeted imaging.
• Future work will optimize protocols, detector spacing, angles, and incorporate advanced reconstruction techniques like TOF and PSF modeling.