Uptake rates of 18F-fluorodeoxyglucose and 11C-choline in lung cancer and pulmonary tuberculosis: a positron emission tomography study.

STUDY OBJECTIVE

The purpose of this study was to examine the uptake rates of (18)F-fluorodeoxyglucose (FDG) and (11)C-choline in patients with lung cancer, pulmonary tuberculosis, and atypical mycobacterial infection of the lung by positron emission tomography (PET) scanning with relation to their tumor size.

DESIGN

Ninety-seven patients with untreated lung cancer, 14 patients with untreated pulmonary tuberculosis, and 5 patients with untreated atypical mycobacterial infection were examined. The diagnosis of lung cancer was confirmed pathologically after biopsy and surgery. The diagnosis of tuberculosis and atypical mycobacterial infection was confirmed by bacterial culture. The uptake rates of FDG and (11)C-choline were presented quantitatively as the standardized uptake value (SUV).

SETTING

International Medical Center of Japan.

RESULTS

In lung cancer patients, the SUV of FDG increased with increasing tumor size, whereas the SUV of (11)C-choline was almost constant at around 3.5 for every tumor size. In tuberculosis patients, the SUV of FDG increased with increasing tumor size, whereas the SUV of (11)C-choline was almost constant at around 2 for every tumor size. In atypical mycobacterial infection patients, the SUV of FDG and the SUV of (11)C-choline were equally low at around < or = 2.

CONCLUSION

The differences in the SUVs of FDG and (11)C-choline in patients with lung cancer, tuberculosis, and atypical mycobacterial infection for the same tumor size (tumor size, > 1.5 cm) were distinct. In lung cancer patients, the SUVs of both FDG and (11)C-choline were high. In tuberculosis patients, the SUV of FDG was high, but the SUV of (11)C-choline was low. In atypical mycobacterial infection patients, the SUVs of both FDG and (11)C-choline were low. It may be possible to apply this principle to make a presumptive diagnosis of a solitary pulmonary nodule if it is too small to make a definitive diagnosis pathologically and bacteriologically.