Dana-Farber Cancer Institute researchers said full-body positron emission tomography, or PET, scanning combined with computed tomography, or CT, scans detected unsuspected, treatable tumors in three of 15 patients with Li-Fraumeni syndrome -- a rare genetic cancer syndrome for which no screening tests have been recommended.

The researchers said their findings suggest periodic scans in combination with physical exams might catch more tumors at a curable stage. But, they cautioned, larger studies are needed to determine whether PET/CT screening is beneficial in LFS patients.

PET detects cancers by tracking their abnormal appetite for glucose, as compared with normal tissues, while computed tomography uses X-rays to show anatomical and structural details, the researchers said. Combining the two modalities in a single machine allows a patient to undergo both exams in one session. The resulting images are superimposed to reveal the precise location of suspected tumors.

The study appears in the March 19 issue of the Journal of the American Medical Association.