Multicenter study of quantitative PET system harmonization using NIST-traceable ⁶⁸Ge/⁶⁸Ga cross-calibration kit

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Standardized Uptake Value (SUV) is crucial for quantitative analysis in Positron Emission Tomography/Computed Tomography (PET/CT).
• Variability in SUV measurements across different PET/CT scanners can hinder multicenter studies and clinical decision-making.
• Harmonization of SUV is essential for consistent and reliable quantitative PET imaging.

Purpose of the Study:

• To define errors in SUV measurements.
• To demonstrate the feasibility of harmonizing SUV across contemporary PET/CT scanners.
• To establish a novel reference standard using a National Institute of Standards and Technology (NIST)-traceable ⁶⁸Ge/⁶⁸Ga source.

Main Methods:

• Utilized a NIST-traceable ⁶⁸Ge/⁶⁸Ga source for dose calibrator and PET source preparation.
• Determined bias in radioactivity and concentration measurements at five Japanese sites.
• Optimized dose calibrator settings and PET reconstruction parameters for SUV harmonization.

Main Results:

• Average bias in radioactivity and concentration measurements reduced from -4.94% and -12.22% to -0.14% and -4.81% post-harmonization.
• Clinical SUV errors improved from -7.66% underestimation to -4.70% under optimal conditions.
• SUV variability was reduced to within 5% across different PET scanner models.

Conclusions:

• The proposed method effectively identified and corrected bias in dose calibrator and PET scanner measurements.
• NIST-traceable ⁶⁸Ge/⁶⁸Ga sources provide a reliable standard for SUV harmonization.
• This protocol shows significant potential for standardizing SUV in multicenter PET/CT studies.