Is there a role for PET in the evaluation of subcentimeter pulmonary nodules?

There are little published data available at this time to determine the appropriate role of positron emission tomography (PET) in the evaluation of subcentimeter pulmonary nodules. The sensitivity for malignancy is lower in these smaller lesions, while one would expect the specificity to be higher. Given that the resolution of current generation PET scanners is only 5 to 6 mm, one will be very unlikely to gain useful information from PET for a lesion below 5 mm. For lesions 5 to 10 mm in size, useful information might be gained from PET in those deemed intermediate risk by CT criteria, but this remains to be established. A positive PET in a small, intermediate risk lesion might push one toward biopsy/excision, though a negative PET in such a lesion must be considered to provide no information whatsoever. Even with advances in PET technologies in the future, we feel it is unlikely that PET will evolve a major role in the evaluation of the subcentimeter nodule.