STANDARDIZED UPTAKE VALUES OF FDG - BODY-SURFACE AREA CORRECTION IS PREFERABLE TO BODY-WEIGHT CORRECTION

Standardized uptake values (SUVs) are widely used to measure F-18-fluo rodeoxyglucose (FDG) uptake in various tumours. It has been reported t hat normalization of FDG uptake for patient body weight (SUVbw) overes timates FDG uptake in heavy patients, as their fraction of body fat (w ith low FDG uptake) is often increased. The objective of this study wa s to determine if ''normalization of FDG uptake for the body surface a rea'' (SUVbsa) is independent of the patient's body size and is more r eliable than SUVbw. Methods: FDG-PET images were acquired on 44 patien ts (body weight range: 45-115 kg) with cancer. SUVbw [(mCi/g of tissue )/(mCi injected/patient body weight in g)] and SUVbsa [(mCi/g of tissu e)/(mCi injected/patient BSA in m(2))] were determined for the liver. Since most observers are accustomed to using the SUVbw, the two values were compared by setting the mean SUVbsa equal to that of SUVbw. Resu lts: SUVbw and SUVbsa were 3.42 +/- 0.85 (mean +/- s.d.) and 3.42 +/- 0.60, respectively. The standard deviation of the SUVbsa was smaller t han that of SUVbw. More importantly, there was a strong positive corre lation between SUVbw and, not only body weight (r = 0.75) but also BSA (r = 0.68), whereas only a weak correlation between SUVbsa and body w eight (r = 0.41) or BSA (r = 0.38) was found with a near flat regressi on line. Conclusion: SUVbw overestimates FDG uptake in large patients. SUVbsa appears preferable to SWbw, since it is minimally affected by the body size.