Increasing the efficiency of the retinoblastoma brachytherapy protocol with ultrasonic hyperthermia and gold nanoparticles: a rabbit model

Purpose This study purposed to evaluate the efficacy of brachytherapy with the modality of ultrasonic hyperthermia in the presence of gold nanoparticles (GNPs) on an ocular retinoblastoma tumor in an animal model of the rabbit. Materials and methods A retinoblastoma tumor was induced by the injection of the human cell line of Y79 in rabbit eyes (n = 41). After two weeks, tumor size reached a diameter of about 5-7 mm. Seven groups were involved: control, GNPs injection, hyperthermia, hyperthermia with GNPs injection, brachytherapy with I-125, a combination of hyperthermia and brachytherapy, and a combination of brachytherapy, hyperthermia and, GNPs. The tumor area was measured using B-mode ultrasound images on the zero-day and at the end of the third week. The groups were evaluated for a histopathological study of tumor necrosis. Results There was a significant difference between the relative area changes of tumor in the combination group with the other study groups (p < .05). The results of histopathologic studies confirmed the necrosis of living retinoblastoma cells. Conclusion Combination therapy of brachytherapy and hyperthermia with GNPs reduces the relative size of the tumor. This method increases the necrosis percentage of retinoblastoma and significantly reduces the retinoblastoma mass in the rabbit eyes.