Figure 3.

Pigs were sacrificed 1 month after the experiment. The infused lung areas illuminated with different light doses were resected for pathological examination. The results of the pathological examination of L1 and R1 show infusion with lipiodol did not cause damage to the alveolar structure. Only some tissue fluid and inflammatory cell infiltration were noted, indicating that the infusion of lipiodol will not lead to severe pulmonary inflammatory response. With the increase of light energy, the normal lung alveolar structure was gradually damaged. The alveolar structure remained normal under 200 J and 400 J, while moderate inflammatory response was observed under 800 J illumination, although most alveolar structures remained unchanged with no severe necrosis and ulceration. This shows that high-energy PDT (800 J) will cause nonfatal damage to the normal lung. The large arrow shows lung injury with proliferation of myofibroblasts and hemorrhage in the interstitium or alveolar septum. The small arrow indicates lipiodol deposition in lung parenchyma (H&E 100×). PDT, photodynamic therapy.