Dose Distribution and Dose Enhancement by Using Gadolinium Nanoparticles Implant in Brain Tumor in Stereotactic Brachytherapy

• High atomic number elements have high photoelectric cross section.
• Radiation dose is enhanced in tumor injected with gadolinium nanoparticles.
• Dose enhancement factor increases with increasing gadolinium concentration.
• Dose enhancement factor increases with decreasing irradiation energy.
• Dose enhancement factor increases with increasing tumor depth.

BackgroundThe photoelectric and pair production processes increase when high-energy photons interact with materials with high atomic number Z. The energy loss results in a dose enhancement at the target implanted with these materials. This will lead to a higher active dose to be delivered to tumor, while sparing healthy tissues around the target volume.Objective and methodThe objective of this work was to compute the radial dose enhancement, using GEANT4 based Monte Carlo simulations, at and near a 1×1×1 cm3 brain tumor implanted with different concentrations of gadolinium nanoparticles when using 192Ir, 137Cs and 60Co, brachytherapy sources with parallel beam geometry.ResultsOur outcomes show a dose enhancement factor of 1.45 for a concentration of 70 mg of gadolinium in the tumor when irradiated with 0.38 MeV γ-photon from 192Ir source. It was also observed that this dose enhancement increased with increasing gadolinium concentration in the target and with photon energy.ConclusionGadolinium nanoparticles are groundbreaking agents with strong advantageous potential in cancer radiotherapy due to the fact that they enhance the radiation dose within the tumor.