Imaging, biodistribution and efficacy evaluation of 188Re-human serum albumin microspheres via intraarterial route in an orthotopic hepatoma model

Purpose: Liver cancer is the second most common cause of death worldwide. This study was to investigate the SPECT/CT, ultrasound, biodistribution and therapeutic evaluation of Re-188-human serum albumin microspheres (Re-188-HSAM) in the GP7TB orthotopic hepatoma rat model.Materials and methods: HSAM was labeled with Re-188 by using a home-made kit and microwave system. The Re-188-HSAM was administered via intraarterial route. The in vivo distribution of Re-188-HSAM was determined by biodistribution analysis and nanoSPECT/CT system. In efficacy, tumor volumes were tracked longitudinally by three-dimensional ultrasound.Results: The biodistribution and nanoSPECT/CT imaging showed that Re-188-HSAM could accumulate in liver and tumor. The correlation coefficient of tumor volumes done by three-dimensional ultrasound and at autopsy was 0.997. In efficacy, tumor volume in the normal saline-treated group was 1803.2mm(3) at 54 days after tumor inoculation. Tumor volumes in the 103.6 MBq and 240.5 MBq of Re-188-HSAM treated groups were 381 and 267.4mm(3) (p=0.001 and 0.004), respectively.Conclusions: These results show that three-dimensional ultrasound with a high spatial resolution and contrast in soft tissue can become imaging modality in assessing tumor burden and tumor progression in an orthotopic rat model. The longitudinally therapeutic evaluation of Re-188-HSAM demonstrated dose-dependent tumor growth inhibition with increased dose in the GP7TB orthotopic hepatoma rat model.