Patient weight-based acquisition protocols to optimize (18)F-FDG PET/CT image quality.

Area of Science:

• Nuclear Medicine
• Radiopharmacy
• Medical Imaging Physics

Background:

• High-quality positron emission tomography (PET) images depend on optimal injected dose and acquisition time of (18)F-FDG.
• Patient weight is a critical factor influencing PET/CT image quality and protocol optimization.

Purpose of the Study:

• To determine optimal (18)F-FDG PET/CT acquisition protocols based on patient weight for 3D lutetium oxyorthosilicate scanners.
• To evaluate the impact of patient weight on PET imaging performance metrics and image quality.

Main Methods:

• Retrospective analysis of 76 patients (29-101 kg) using (18)F-FDG PET/CT.
• Patients categorized into four weight groups; measured true coincidence rate, random coincidence rate, noise-equivalent counting rate (NECR), and random fraction.
• Image quality assessed via coefficient of variance (COV) in liver slices.

Main Results:

• True coincidence rate, random coincidence rate, and NECR increased significantly with injected dose per kilogram (P < 0.01).
• NECR peaked at 10.11 MB/kg in underweight patients; true coincidence rate varied significantly across weight groups (P < 0.01).
• Overweight patients exhibited higher COVs and poorer image quality compared to underweight patients.

Conclusions:

• Acquisition protocols for (18)F-FDG PET/CT were modified based on patient weight and 3D lutetium oxyorthosilicate scanner characteristics.
• Optimal acquisition time is 1.4-1.6 times longer for overweight patients compared to normal-weight patients.
• Utilizing the true coincidence rate for estimating optimal acquisition times is crucial for enhancing PET image quality.