Using a special MRI scanner, technicians like the on in the photo can image a patient's entire body in about 45 minutes. (Credit: Porter Gifford)

A green, red, black, and white 3-D image of a patient's entire body rotates on a computer screen before Gordon Harris and Wenli Cai. Harris points out a number of tumors, hallmarks of a genetic disease called ­neurofibromatosis (NF). ­Harris's research group at Massachusetts ­General ­Hospital, where he is director of 3-D-imaging services, is preparing a clinical trial to test a technique for monitoring patients, like this one, affected by NF. The technique combines PET imaging and a relatively new imaging technology called whole-body MRI. [Disclaimer: Jason Pontin, the editor in chief and publisher of Technology Review, serves on the board of directors of the Children's Tumor Foundation, which awarded a grant to Harris for the research described here.]

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