Longitudinally therapeutic evaluation of 188Re-human serum albumin microsphere in hepatoma model by three-dimensional ultrasound imaging: Longitudinally therapeutic evaluation of 188Re-HSAM

The aim of this study was to investigate the utility of three-dimensional (3D) high-frequency ultrasound in the longitudinally therapeutic evaluation of ¹⁸⁸Re-human serum albumin microspheres (¹⁸⁸Re-HSAM) in a GP7TB hepatoma model. Male F344 rats were intrahepatic inoculation with GP7TB 1 mm³ cubes. Studies were performed on rat at 26 days after tumor inoculation. The efficacy of ¹⁸⁸Re-HSAM was performed by a single-dose treatment in GP7TB hepatoma rats via intraarterial route. Rats were monitored for survival until death. The body weight was measured once a week. To monitor the tumor growth, longitudinal tumor volumes were obtained from 3D segmentation of ultrasound imaging in the F344 rats with GP7TB hepatoma once a week. The tumor volumes were inhibition with time after i.a. injection of ¹⁸⁸Re-HSAM. In contrast to the mean tumor volume of 1803.2 ± 306.8 mm³ in the treated normal saline group at 54 days, the mean tumor volumes of the treated groups were 381 ± 95.1 and 267.4 ± 54.7 mm³ at 54 days administration of 2.8 mCi and 6.5 mCi ¹⁸⁸Re-HSAM, respectively. The mean growth inhibition rates achieved by 2.8 mCi and 6.5 mCi ¹⁸⁸Re-HSAM were 0.21 and 0.15, respectively. The 3D high-frequency ultrasound with a high spatial resolution and contrast in soft tissue can become imaging modality for rat preclinical studies. The longitudinally therapeutic evaluation of ¹⁸⁸Re-HSAM demonstrated better tumor growth inhibition for rat with increased dose in the GP7TB hepatoma model. These results suggested that intraarterial administration of ¹⁸⁸Re-HSAM could provide a benefit and promising strategy for delivery of radiotherapeutics in oncology applications.