Acquisition Duration Optimization Using Visual Grading Regression in [⁶⁸Ga]FAPI-46 PET Imaging of Oncologic Patients

Area of Science:

• Oncologic molecular imaging
• Radiopharmaceutical therapy
• Positron Emission Tomography/Computed Tomography (PET/CT)

Background:

• Fibroblast activation protein inhibitors (FAPI) are effective for molecular imaging in various cancers.
• Optimal FAPI PET/CT imaging protocols, particularly acquisition duration, require standardization.
• Balancing scan time with diagnostic image quality is crucial for reliable cancer diagnosis.

Purpose of the Study:

• To evaluate the feasibility of shortening [68Ga]FAPI-46 PET/CT imaging acquisition duration.
• To assess the impact of reduced scan times on image quality and diagnostic accuracy.
• To determine the minimum acquisition duration for satisfactory FAPI PET/CT imaging.

Main Methods:

• Ten patients with suspected pancreatic cancer underwent [68Ga]FAPI-46 PET/CT.
• Acquisition times were reduced to 1, 2, and 3 minutes per bed position from a 4-minute reference.
• Image quality was assessed using four criteria (anatomic detail, noise, overall quality) on a 4-point Likert scale.

Main Results:

• Overall image quality was comparable between 3-minute and 4-minute acquisitions.
• Acquisition times of 1 and 2 minutes resulted in significantly lower image quality scores.
• Reduced scan durations (1-3 min) showed inferior performance in distinguishing anatomic details and increased noise compared to 4 minutes.

Conclusions:

• FAPI PET/CT acquisition duration can be reduced to 3 minutes per bed position without compromising satisfactory image quality.
• Scan durations of 2 minutes or less are not recommended due to significantly disrupted clinical interpretation from image noise and degradation.
• Optimized FAPI PET/CT protocols can balance efficiency and diagnostic reliability in oncologic imaging.