What is suv on a pet scan?

A measure: Standardized uptake value. There are a normal range of suvs for various organs and too low of a range and too high of a range.

StandardUptakeValue: Suv simply stands for standard uptake value of a certain area on a scan (lesion, lymph node, etc). This is typically used to standardize pet scans between institutions and physicians. Studies show that maximum suvs of certain lesions are more indicative of cancer. This takes out some of the subjectiveness of reading the studies because by looking at this value, one can decide if it is high or low.

Tracer uptake: Standardized uptake value is the measured activity normalized for body weight/surface area and injected dose. In an fdg-pet scan tissues that have high suv value (usually above 30% of liver background) are indicative of an underlying process where glucose is being consumed at a higher rate than normal (e.g. Cancer or inflammation).