Application of X-ray Phase Contrast Imaging Technique in Detection of Pulmonary Lesions Induced by Multi-WalledCarbon Nanotubes in Rats

With X-ray phase contrast imaging technique, the pulmonary lesions induced by multi-walled carbon nanotubes were preliminarily studied in this work. After 0.1, 1 and 2 mg nanotubes were delivered into lungs of rats via trachea, their acute pulmonary toxicity (at 5-day postexposure) was assessed using X-ray phase contrast, absorption contrast imaging and routine pathological slice techniques. As such, the long-term pulmonary toxicity (at 140-day postexposure), induced by single intratracheal instillation of 0.1 mg nanotubes, was assessed using X-ray phase contrast imaging and pathological slice techniques. As a consequence, the nanotubes could induce obvious density and structural integrity alternation in lung tissue at 5-day postexposure and granulomas at 140-day postexposure, and these pathologic lesions could be efficiently detected out with the phase imaging technique. By comparison, this technique not only gained advantage over the conventional X-ray absorption contrast imaging but also could supply the gap of routine pathological slice in detecting pulmonary lesions induced by carbon nanotubes. It is hoped that this work can act as an impetus for further application of phase imaging technique to nanotoxicology and to assessment of occupational safety of nanomaterials.