Dose enhancement by various nanoparticles in prostate brachytherapy

Area of Science:

• Medical Physics
• Radiotherapy
• Nanotechnology

Background:

• Prostate brachytherapy using Iodine-125 ((125)I) implants is a common cancer treatment.
• Optimizing radiation dose delivery within tumors is crucial for treatment efficacy.
• Nanoparticles offer potential for modulating radiation dose in targeted therapies.

Purpose of the Study:

• To calculate the dose enhancement in prostate tumors using various nanoparticles with (125)I brachytherapy.
• To evaluate the impact of different nanoparticle types and concentrations on radiation dose distribution.
• To assess the potential of nanoparticles as an adjunct therapy in prostate brachytherapy.

Main Methods:

• Monte Carlo simulation using the MCNPX code to model the ProstaSeed (125)I brachytherapy source.
• Calculation of dose enhancement factors (DEFs) for iron oxide (Fe2O3), silver (Ag), gadolinium (Gd), platinum (Pt), and gold (Au) nanoparticles.
• Simulation of nanoparticle concentrations at 7, 18, and 30 mg/ml within a spherical prostate tumor model.

Main Results:

• The source simulation was validated against published data.
• Maximum dose enhancement factors at 30 mg/ml concentration were highest for gold (1.79), followed by platinum (1.32), iron oxide (1.27), silver (1.15), and gadolinium (1.14).
• Gold nanoparticles at 30 mg/ml concentration showed the most significant dose enhancement, leading to isodose line changes that could improve tumor coverage and spare surrounding tissues.

Conclusions:

• Nanoparticles can increase radiation dose within prostate tumors, potentially allowing for reduced treatment time or source activity.
• Gold nanoparticles demonstrate the highest dose enhancement potential at higher concentrations.
• Nanoparticles represent a promising tool for enhancing the effectiveness of prostate brachytherapy, warranting further preclinical investigation.