What it means
On a PET scan, the tracer, often FDG, spreads through the body and collects more in active tissue. SUV turns that into a number. A value of 1 means a spot holds about as much tracer as if it were spread evenly through the body. Higher numbers mean more uptake. SUVmax, the most quoted figure, is the single brightest point in the spot. The liver or the blood in large vessels often serves as a normal reference.
When it matters
No single SUV number separates cancer from harmless causes. Infection, inflammation and healing can read high, and some slow-growing cancers read low. The number also shifts with blood sugar, scan timing and the machine used. That is why the change between scans, ideally done the same way, often says more than one value. A falling SUV during treatment usually suggests the treatment is working.
Questions to ask your doctor
- What was the SUV, and how does it compare with my last PET scan?
- Could inflammation or infection explain this level of uptake?
- Were my scans done in a similar way, so the numbers can be compared?
Read more: Hypermetabolic and SUV on a PET-CT Scan: What They Mean
