Diffuse gallium-67 uptake in radiation pneumonitis.

To evaluate the clinical usefulness of Ga-67 imaging for the assessment of radiation pneumonitis, 12 patients who had developed radiation pneumonitis after receiving radiotherapy alone for non-small-cell lung cancer from 1979 through 1988 were reviewed. Diffuse bilateral Ga-67 uptake occurred in 5 out of the 12 cases; in the other 7 cases, Ga-67 uptake was confined to the irradiation lung. Conversely, chest radiography showed infiltrates only in the irradiated lung. Histopathology of the lung in four out of the five cases that showed diffuse Ga-67 uptake in the lung, however, revealed that the lung outside the radiation field with Ga-67 uptake was consistent with interstitial pneumonitis induced by radiation. These results suggest that radiation pneumonitis could extend beyond the irradiated lung and that Ga-67 imaging is more useful than chest radiography for the assessment of the spatial extent of radiography pneumonitis.