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

Abstract

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 ¹⁸⁸Re-human serum albumin microspheres (¹⁸⁸Re-HSAM) in the GP7TB orthotopic hepatoma rat model.

Materials and methods: HSAM was labeled with ¹⁸⁸Re by using a home-made kit and microwave system. The ¹⁸⁸Re-HSAM was administered via intraarterial route. The in vivo distribution of ¹⁸⁸Re-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 ¹⁸⁸Re-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 1803.2 mm³ at 54 days after tumor inoculation. Tumor volumes in the 103.6 MBq and 240.5 MBq of ¹⁸⁸Re-HSAM treated groups were 381 and 267.4 mm³ (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 ¹⁸⁸Re-HSAM demonstrated dose-dependent tumor growth inhibition with increased dose in the GP7TB orthotopic hepatoma rat model.

Keywords:

• ¹⁸⁸Re-HSAM
• GP7TB orthotopic hepatoma model
• SPECT/CT
• three-dimensional ultrasound
• intraarterial route

Acknowledgements

The authors thank Dr Y.C. Lin for providing us with the GP7TB cell line, Mr M.S. Lin and Dr C.Y. Li for providing us with the rhenium-188, and Mr C.L. Ho and Mr H.L. Yu for their technical support and assistance in the animal tumor model.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.