3:09 PM Abstract No. 128 Development of real-time optical image-assessed thermal ablation of hepatic tumor

Abstract

To investigate the feasibility of using indocyanine green (ICG)-based optical imaging to instantly assess the effective radiofrequency ablation (RFA) on VX2 tumor cells, towards the development of intratumoral real-time optical imaging-guided RFA of larger tumors. We first optimized the uptake characteristics of a clinically applicable optical contrast, indocyanine green (ICG), by VX2 tumor cells. 1×104 VX2 cells in each of different cell groups were treated with various ICG concentrations from 0 to 125 μg/mL, over incubation times from 0 min to 48 hours. Then, in comparison to ICG solution-only, ICG-labeled VX2 cells were treated by thermal ablation at 80 °C for 30 minutes. ICG in cells were subsequently qualitatively and quantitatively evaluated by fluorescence microscopy and optical imaging. The optimization of the ICG concentration demonstrated a linear increase of fluorescent signal intensities (SI), with the peak SI at 100 μg/mL of ICG, starting at the time point of 24 hours post-ICG labeling. Both the fluorescent SIs of ICG-only and ICG-labeled VX2 cell groups were significantly decreased after the thermal ablation treatment (For ICG solution: average SI pretreatment vs. SI posttreatment = 11075.2 ± 1060.9 count vs. 4681.1 ± 442.1 count, P <0.001; and for ICG-labeled VX2 cells: 926.2 ± 197.1 count vs. 301.4 ± 53.9 count, P <0.001). This study demonstrated the feasibility of using indocyanine green (ICG)-based optical imaging to evaluate the instant treatment effect of thermal ablation on VX2 tumor cells, which has encouraged the further on-going studies for developing the new interventional molecular imaging technique to ensure the complete removal of larger tumors during a single RFA session.