Technetium-99m-HMPAO as a marker of chemical and irradiation lung injury: experimental and clinical investigations.

Unlabelled: We evaluated the ability of 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) to serve as a sensitive marker of lung injury.

Methods: Two experimental rabbit models of minimal lung injury were designed using injections of a low dose (0.05 ml/kg) of oleic acid or 50 Gy of irradiation. In addition, we clinically investigated whether patients who received chemotherapy (n = 14) or radiotherapy (n = 13) for lung cancer showed high uptake of 99mTc-HMPAO in the lungs.

Results: Despite the minimal endothelial lesions visualized by electron microscopy (edematous changes and blebbing), in both animal models, the lungs showed high uptake of 99mTc-HMPAO, which occurred rapidly within 1 min after injection. Clinically, the mean lung-to-liver ratio of 99mTc-HMPAO activity in the patients who received chemotherapy (0.649 +/- 0.185, p < 0.01) was significantly higher than that of the controls (n = 16; 0.387 +/- 0.108), and all 12 patients who received more than 30 Gy of irradiation showed abnormal uptake in the irradiated lungs, despite the lack of abnormal opacities on chest CT.

Conclusion: These findings suggest that 99mTc-HMPAO has the potential to be a sensitive marker of chemical and irradiation lung injury.