Cancer cells need glucose to thrive. Scientists take advantage of cancer’s hunger for this sugar by using 18F-fluorodeoxyglucose, or 18F-FDG, to visualize tumors with positron emission tomography. But 18F-FDG doesn’t do a great job of imaging invasive brain tumors called gliomas. That’s because brain cells also consume a lot of glucose, leading to high background uptake of the radiotracer in the brain. Researchers led by Jason S. Lewis and Craig B. Thompson of Memorial Sloan Kettering Cancer Center and Sriram Venneti of the University of Michigan, Ann Arbor, have come up with a way to more effectively visualize the activity of gliomas using another compound cancer cells love to gobble up: glutamine. The researchers showed that a radiolabeled version of the amino acid, 18F-FGln, has high uptake in gliomas and low uptake in the rest of the brain (Sci. Transl. Med. 2015, DOI: 10.1126/scitranslmed.aaa1009). Using 18F-FGln, the researchers were able to assess the tumors’ metabolism of nutrients, clueing the team in to the gliomas’ activity. Being able to track brain tumors in this manner, they say, could give doctors a valuable tool for monitoring their progression.