Total-Body PET System Designs with Axial and Transverse Gaps: A Study of Lesion Quantification and Detectability

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiological Physics

Background:

• High-sensitivity total-body PET scanners offer advantages like faster scans and lower radiation doses.
• The high cost of long axial field of view (AFOV) scanners limits their widespread adoption.
• Investigating cost-effective sparse PET designs is crucial for broader clinical implementation.

Purpose of the Study:

• To evaluate the impact of sparse total-body PET designs on lesion quantification and detectability.
• To assess different sparse configurations (axial gaps, transverse gaps, mixed gaps) and their detector fractions (DFs).
• To determine the trade-offs between cost reduction, image quality, and performance in sparse PET systems.

Main Methods:

• Utilized the PennPET Explorer (PPEx) as a model for simulating sparse PET scanner designs.
• Emulated sparse configurations (axial gaps, transverse gaps, mixed gaps) with detector fractions from 71% to 40%.
• Used human data to emulate missing detectors and embedded lesions in lung and liver for analysis of detectability and quantification.

Main Results:

• Axial gap designs showed susceptibility to artifacts as detector fraction decreased.
• Transverse gap designs required longer scan times and experienced field-of-view truncation.
• Mixed gap designs with 58% detector fraction showed no artifacts and comparable performance with increased scan time.

Conclusions:

• Sparse total-body PET designs can achieve comparable lesion quantification and detectability to fully populated systems by increasing scan time.
• Mixed gap designs offer the greatest potential for cost reduction while maintaining image quality.
• Sparse PET technology presents a viable solution for reducing the cost of advanced PET systems for clinical use.