A dedicated paediatric [¹⁸F]FDG PET/CT dosage regimen.

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Pediatric Imaging

Background:

• The use of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) PET/CT in pediatric patients is growing.
• Optimizing pediatric dosage regimens is essential to minimize radiation exposure and reduce cancer risks.
• Current dosing protocols may not be suitable for children, necessitating tailored approaches.

Purpose of the Study:

• To investigate the relationship between patient-specific parameters and FDG PET image quality in children.
• To propose a dedicated pediatric dosage regimen for FDG PET/CT scans.
• To determine if a universal dosing regimen for both pediatric and adult patients is feasible.

Main Methods:

• A retrospective analysis of 102 children and 85 adults undergoing FDG PET/CT scans.
• Image quality was assessed using the signal-to-noise ratio (SNR) in the liver, normalized for administered activity and acquisition time.
• Curve fitting analysis was performed using body weight, length, BMI, and BSA to establish a predictive model for optimal SNR.

Main Results:

• Body weight showed the strongest correlation with image quality, with high coefficients of determination for both linear and nonlinear models (R² ≈ 0.80-0.81).
• A nonlinear model was preferred based on the Akaike's information criterion.
• The proposed regimen, using a target SNR of 6.5, allows for a significant reduction in administered activity compared to current pediatric guidelines.

Conclusions:

• Pediatric body weight is the primary determinant of FDG PET image quality.
• A dedicated nonlinear dosage regimen based on body mass is proposed to ensure consistent image quality and reduce effective radiation doses in children.
• A universal dosing regimen for pediatric and adult patients is not feasible, highlighting the need for specialized pediatric protocols.