Enhanced radiotherapy by novel class of radiosensitizers based bismuth and gadolinium nanoparticles

Purpose or Objective
Recently, the use of nanoparticles with a high atomic number as a new class of radiation sensitizers, to increase the tumor dose and sparing normal tissues has become a hot topic in radiotherapy treatments. Meanwhile, Bismuth and Gadolinium based nanoparticles, can not only be used in CT and MRI as contrast agents, but also can be feasible radiosensitizers in radiotherapy. Hence, they are attractive candidates for multimodal dose enhancement studies. In this study, the ability of dose enhancement of these nanoparticles using MAGIC-f polymer gel under the internal Iridium-192 and the external Cobalt-60 radiotherapy practices were investigated.
Material and Methods
The Bi2O3-NPs less than 40 nm in diameter and 0.1 mM concentration were synthesized. To increase the precision of the gel dosimetry a Plexiglas phantom was designed and made, all of the gel filled vials (with and without the nanoparticles) were irradiated to an Ir-192 radioactive source simultaneously. Also, Irradiation was carried out with a Co-60 teletherapy unit.
Results
The maximum dose enhancement factors under the internal Iridium-192 radiotherapy were 31% and 22% in the presence of Bi2O3-NPs and Gd2O3-NPs, respectively, whereas these amounts were reduced to 1% in external radiotherapy by Co-60 photons.
Conclusion
The result of our research approves the use of Bismuth and Gadolinium based nanoparticles in brachytherapy. Additionally, the polymer gel dosimetry can be a feasible material for verification and estimation of dose enhancements in the presence of nanoparticles.