Study of the Sm-153 seeds degradation and evaluation of the absorbed dose in rabbit's liver implants

Bioceramics are attractive for radiation therapy. Implants in animals made of bioglasses of Si–Ca–Sm-153 will be addressed. Herein, the biocompatibility and biodegradability of Sm ceramic seeds produced by the sol–gel process are investigated, as well as, it will analyze the absorbed doses produced by the beta and gamma particles generated by Sm-153 decay, in the rabbit's liver. A set of Sm seeds was implanted in the liver of a rabbit. The high ecogenicity of the seed in the liver turns it easily identifiable in ultrasonography. The capacity of absorption of the seeds was investigated in the organ monitored by ultrasonography. Seven months later, after radiological exploration, the seeds showed to be absorbed in the liver. The biodegradability was also verified by X-ray, attesting what had already been observed in the ultrasonography. A computational model was also elaborated to predict absorbed doses in multiple seed's arrangements. CT images of the thoracic–abdominal area of the rabbit were digitalized and used to produce the voxel computational model. Dosimetry was accomplished through the MCNP5 code. Spatial dose rate distribution in the liver is presented. The results will help in future the project of the radioactive implants using hot-ceramic-seeds.