IR780-based diffuse fluorescence tomography for cancer detection

IR780 is widely used as a commercially available near infrared contrast agent due to superior optical properties and tumor targeting capacity, while is a photosensitizer for photothermal (PTT) and photodynamic therapy (PDT). However, few articles reported the accumulation, dynamics and retention of IR780 in tumor. In the work, we explored the accumulation and retention of IR780 in tumor by quantitatively recovering the three-dimensional distributions of IR780 using a home-made diffuse fluorescence tomography (DFT) prototype system. The results showed that DFT can effectively identified multiple tumor targets with a significant tumor-to-normal-tissue ratio simultaneously. The kinetics of fluorescent signals in tumors and liver showed that IR780 was quickly cleared from the liver, whereas exhibited much higher tumor retention over 7days. Ex vivo imaging of dissected organs and fluorescence signal analysis revealed that IR780 was mainly concentrated in tumor and lung with significantly different from the distribution in other organs, suggesting that IR780 had excellent tumor homing ability.