In vivo observing x-ray attenuation of intratumor injection of indocyanine green

We report our experimental results of in vivo observing x-ray attenuation of intra-tumor injection of indocyanine green (ICG). An eight- to nine-week-old male BALB/c mouse weighting between 15 and 20 g is used in the experiments, which has been implanted with myeloma cell line (SP2/0) two week before. The system used to monitor the intratumor diffusion of ICG is a digital x-ray imaging system. It works at 33kVp, 0.3mAs, 4 seconds and 1.5×magnification. The objective of this research is to study the x-ray attenuation at different area, which represented by gray-scale value. Compare to the ROI in the tissue without ICG and ROI of black background in the image, there is an obvious change before and after injecting ICG in the tumor, which is the area ICG can diffuse to. It shows the feasibility of using digital x-ray imaging system to dynamically, effectively and noninterventionly monitor the diffusion of the ICG.