Standardized uptake value (SUV)

Last revised by Liz Silverstone on 7 Oct 2023

The standardized uptake value (SUV) applies to PET imaging of tumors and typically uses the radioligand F18-2-fluoro-2-deoxy-D-glucose (FDG). The concentration of F18 activity reflects glucose metabolism which is increased in tumor cells and inflammation.

SUV is also known as the dose uptake ratio (DUR) and is a mathematically derived ratio of tissue radioactivity concentration at a point in time C(T) at a specific region of interest (ROI) and the injected dose of radioactivity per kilogram of the patient's body weight 7:

SUV = C(T)/[injection dose (MBq)/patient's weight (kg)] 

FDG PET-CT is used to detect malignancy and measure treatment response however the values can be measured in different ways as ‘max’, ‘mean’ or ‘peak’ and are vulnerable to biological and technical sources of variation 7. Uptake values are sometimes normalized to lean body mass (LBM) or body surface area. However body weight is the most commonly used because it is easy to calculate and is reproducible 7.

SUV may be influenced by biological and technical factors such as blood glucose level, image noise, image resolution and variable region of interest selection. The cut off between benign and malignant lesions is in the SUV range of 2.0-2.5 however infectious and inflammatory conditions also demonstrate hypermetabolism. FDG PET sensitivity and specificity decreases with lesions smaller than 7 mm.

Follow-up imaging on the same scanner and using the same method improves the reliability of serial SUV measurements.

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