Current Methods to Define Metabolic Tumor Volume in Positron Emission Tomography: Which One is Better?

Overestimation of MTV by a fixed absolute threshold. A patient with melanoma had a metabolically active soft tissue metastasis in left peritoneal space with SUVmax of 80.8. Tumor segmentation using a threshold of SUV 2.5 resulted in overestimation of the tumor volume because of spillover effect of FDG PET image. Red volume of interest indicates MTV using threshold of SUV 2.